Penguinology

Winged Dinosaur Archaeopteryx Dressed for Flight

2012-01-26T13:06:00.000-08:00

Berlin specimen of Archaeopteryx: Paleontologists have long thought that Archaeopteryx fossils, including this one discovered in Germany, placed the dinosaur at the base of the bird evolutionary tree. (Credit: Museum für Naturkunde Berlin)

ScienceDaily (Jan. 24, 2012) — Since its discovery 150 years ago, scientists have puzzled over whether the winged dinosaur Archaeopteryx represents the missing link in birds' evolution to powered flight. Much of the debate has focused on the iconic creature's wings and the mystery of whether -- and how well -- it could fly.

Some secrets have been revealed by an international team of researchers led by Brown University. Through a novel analytic approach, the researchers have determined that a well-preserved feather on the raven-sized dinosaur's wing was black. The color and parts of cells that would have supplied pigment are evidence the wing feathers were rigid and durable, traits that would have helped Archaeopteryx to fly.

The team also learned from its examination that Archaeopteryx's feather structure is identical to that of living birds, a discovery that shows modern wing feathers had evolved as early as 150 million years ago in the Jurassic period. The study, which appears in Nature Communications, was funded by the National Geographic Society and the U.S. Air Force Office of Scientific Research.

"If Archaeopteryx was flapping or gliding, the presence of melanosomes [pigment-producing parts of a cell] would have given the feathers additional structural support," said Ryan Carney, an evolutionary biologist at Brown and the paper's lead author. "This would have been advantageous during this early evolutionary stage of dinosaur flight."

The Archaeopteryx feather was discovered in a limestone deposit in Germany in 1861, a few years after the publication of Charles Darwin's On the Origin of Species. Paleontologists have long been excited about the fossil and other Archaeopteryx specimens, thinking they place the dinosaur at the base of the bird evolutionary tree. The traits that make Archaeopteryx an evolutionary intermediate between dinosaurs and birds, scientists say, are the combination of reptilian features (teeth, clawed fingers, and a bony tail) and avian features (feathered wings and a wishbone).

The lack of knowledge of Archaeopteryx's feather structure and color bedeviled scientists. Carney, with researchers from Yale University, the University of Akron, and the Carl Zeiss laboratory in Germany, analyzed the feather and discovered that it is a covert, so named because these feathers cover the primary and secondary wing feathers birds use in flight. After two unsuccessful attempts to image the melanosomes, the group tried a more powerful type of scanning electron microscope at Zeiss, where the group located patches of hundreds of the structures still encased in the fossilized feather.

"The third time was the charm, and we finally found the keys to unlocking the feather's original color, hidden in the rock for the past 150 million years," said Carney, a graduate student in the Department of Ecology and Evolutionary Biology, studying with Stephen Gatesy.

Melanosomes had long been known to be present in other fossil feathers, but had been misidentified as bacteria. In 2006, coauthor Jakob Vinther, then a graduate student at Yale, discovered melanin preserved in the ink sac of a fossilized squid. "This made me think that melanin could be fossilized in many other fossils such as feathers," said Vinther, now a postdoctoral researcher at the University of Texas-Austin. "I realized that I had opened a whole new chapter of what we can do to understand the nature of extinct feathered dinosaurs and birds."

The team measured the length and width of the sausage-shaped melanosomes, roughly 1 micron long and 250 nanometers wide. To determine the melanosomes' color, Akron researchers Matthew Shawkey and Liliana D'Alba statistically compared Archaeopteryx's melanosomes with those found in 87 species of living birds, representing four classes: black, gray, brown, and a type found in penguins. "What we found was that the feather was predicted to be black with 95 percent certainty," Carney said.
Next, the team sought to better define the melanosomes' structure. For that, they examined the fossilized barbules -- tiny, rib-like appendages that overlap and interlock like zippers to give a feather rigidity and strength. The barbules and the alignment of melanosomes within them, Carney said, are identical to those found in modern birds.

What the pigment was used for is less clear. The black color of the Archaeopteryx wing feather may have served to regulate body temperature, act as camouflage or be employed for display. But it could have been for flight, too.

"We can't say it's proof that Archaeopteryx was a flier. But what we can say is that in modern bird feathers, these melanosomes provide additional strength and resistance to abrasion from flight, which is why wing feathers and their tips are the most likely areas to be pigmented," Carney said. "With Archaeopteryx, as with birds today, the melanosomes we found would have provided similar structural advantages, regardless of whether the pigmentation initially evolved for another purpose."

Contributing authors include Vinther, Shawkey, D'Alba, and Jörg Ackermann from Carl Zeiss.

Story Source:

The above story is reprinted from materials provided by Brown University.

Journal Reference:

Ryan M. Carney, Jakob Vinther, Matthew D. Shawkey, Liliana D'Alba, Jörg Ackermann. New evidence on the colour and nature of the isolated Archaeopteryx feather. Nature Communications, 2012; 3: 637 DOI: 10.1038/ncomms1642

Brown University (2012, January 24). Winged dinosaur Archaeopteryx dressed for flight. ScienceDaily. Retrieved January 26, 2012, from http://www.sciencedaily.com /releases/2012/01/120124113036.htm

Happy New Year! from Penguinology

2011-12-31T20:40:00.000-08:00

Dino-Chicken???

2011-12-27T14:01:00.000-08:00

Dino-Chicken: Wacky But Serious Science Idea of 2011

Stephanie Pappas, LiveScience Senior Writer

Date: 27 December 2011

Evolution in reverse: Could this chicken become a dinosaur?
CREDIT: sanddebeautheil, Shutterstock

View full size image

Paleontologist Jack Horner has always been a bit of an iconoclast. In the 1970s, Horner, the curator of paleontology at the Museum of the Rockies in Bozeman, Mont., and his friend Bob Makela discovered a Maiasaura nesting site, painting the first picture of dinosaurs as doting moms and dads. He's also been at the forefront of research suggesting that dinosaurs were fast growing and warm-blooded.

But Horner's newest idea takes iconoclasm to a new level. He wants, in short, to hatch a dinosaur.

Or something very much like one, at least. Horner, who served as a technical advisor for the "Jurassic Park" movies, has no illusions that the technique in that movie — extracting dino DNA from mosquitoes in amber — would work. DNA degrades too quickly, for one thing. Dinosaur DNA has proved impossible to extract from actual dinosaur bones, never mind blood-sucking insects.

"If you actually had a piece of amber and it had an insect in it, and you drilled into it, and you got something out of that insect and you cloned it, and you did it over and over and over again, you'd have a room full of mosquitoes," Horner said in a February 2011 TED Talk in Long Beach, Calif. TED, or Technology, Entertainment and Design, is a nonprofit focusing on "ideas worth spreading."

So Horner has another idea: Use the living dinosaurs among us to recreate creatures dead for millions of years. Anyone who's seen "Jurassic Park" knows that birds are dinosaurs, part of the evolutionary line containing those toothy Velociraptors. What's less known is that organisms carry their evolutionary history with them. Human embryos, for example, have temporary tails, which are absorbed by the body during development. Rarely, babies are born with vestigial tails, the result of scrambled genetic processes that prevent the tail from getting re-absorbed. These evolutionary remnants are called atavisms.

Enough atavisms have been discovered in birds to make the idea of "reverse-engineering" a dinosaur out of, say, a chicken possible, Horner says. You wouldn't be adding anything to the bird to make it more dinosaurlike; all the ingredients are in its DNA. Horner's goal is to figure out how to wake up those ingredients.

LiveScience talked with Horner about his "chickenosaurus" plan and what sort of dinosaur he'd like to keep as a pet.

LiveScience: What was the genesis of this chickenosaurus idea?

Horner: Knowing that birds descended from dinosaurs and knowing the changes that occur from dinosaurs to birds, we know that the changes that did occur occurred because of genetics.
A friend of mine, Hans Larsson at McGill University, was studying some of these changes and looking into how it was that dinosaurs lost their tails in the transformation from dinosaurs to birds. They also transformed their arms from a hand and an arm to a wing. I got to thinking, if he discovered the genes that were responsible for both of those transformations, we could just simply reverse evolution and reactivate the tail, and possibly make a hand back out of the wing.
And then what we would have by doing those two things, you'd actually take a bird and turn it into an animal that looked a lot like one of the meat-eating dinosaurs. It seemed like a good idea.

LiveScience: What kind of animal would chickenosaurus be?

Horner: It's still a chicken. It's a modified chicken. You'd really have to mess with the DNA to make it something different.
The most important thing is that you cannot activate an ancestral characteristic unless the animal has ancestors. So if we can do this, it definitely shows that evolution works.

LiveScience: You've mentioned in the past that you see this dino-chicken as a teaching tool to help people understand evolution. Do you see that working?

Horner: Of course. You bet. There are people who are misinformed, and there are people who are uninformed [about the validity of evolution]. If people are uninformed, this will probably get through to them. If they've been misinformed and don't mind being misinformed, then they probably will continue to be misinformed.

LiveScience: Either way, it'd be a pretty awesome thing to take into a classroom.

Horner: Yes, it would. Exactly.

LiveScience: Starting with a chicken, how close could we really get to what a dinosaur looked like?

Horner: We're working with an animal that has all the right stuff. It's more about subtle changes, adding a tail or fixing a hand or possibly adding teeth, what we would think of as being relatively simple changes rather than messing with physiology or something like that.
A bird is really a dinosaur, so we're pretty sure that the breathing apparatus of a bird evolved from the breathing apparatus of a dinosaur, and is therefore completely different than a mammal. The physiology of a bird is evolved from a dinosaur and not from a mammal, so it's not like we're trying to take a mammal and turn it into a dinosaur.

LiveScience: Would chickenosaurus teach us anything about dinosaurs we can't learn from fossils?

Horner: It's not really about understanding dinosaurs at all. Once we learn what certain genes do and how to turn them on and turn them off, then we have great potential of solving some medical mysteries. There are a lot of ways to think about this, but it's not really about dinosaurs other than solving Hans Larsson's problem of figuring out how birds lost their tails. [Tales of 10 Vestigial Limbs]

LiveScience: What do you see as the biggest challenge of making chickenosaurus happen?

Horner: The biggest challenge, first off, is to find the genes. We know that in the development of a tail, there are a variety of things that have to happen, so there are a couple of ways to possibly go about this.
One, as we know, when a chicken embryo is developing in the egg, just like basically all animals, the embryo actually for a time has a tail and then the trail re-absorbs. So if we could find the gene that re-absorbs the tail and not allow that gene to turn on then we could potentially hatch a chicken with a tail.
The other method would be simply to go in and discover what Hox genes [the genes that determine the structure of an organism] might be responsible for actually adding tail vertebrae, and then to see if we could add some, either by manipulating the Hox genes or by using temperature. There have been some experiments done showing that adding heat will add a vertebra here or there.

LiveScience: Where are you in this process now?

Horner: Right now, mostly I'm looking for a postdoctoral researcher. An adventurous postdoc who knows a lot about developmental biology and a little bit about birds and has done some work about chickens to work in our lab here in Bozeman.
Me, I just go through the literature, looking for anything that might give me a clue as to what genes might be responsible for tail absorption or tail growth or something that might help me with hands.

LiveScience: The comparisons to "Jurassic Park" are easy to make, but have you ever seen the movie "The Birds?" Do we really want chickens with extra teeth and claws running around?

Horner: You can't really compare it to either movie. First off, you can go out in the Serengeti and there are all kinds of animals that will eat you, but if you're driving around in your Jeep, you're just fine. The lions and cheetahs and leopards are not going to try to get into your Jeep when there are plenty of plant-eaters out there to eat that aren't inside of a metal cage.
That's the funny thing about "Jurassic Park," right? All these dinosaurs want to eat people no matter how hard they are to get.
So we don't have to worry about "Jurassic Park," because that's just fiction. Animals don't act that way. They're not vengeful. And birds aren't vengeful either.

LiveScience: So if you could bring a dinosaur back — the real thing, not a modified chicken — what species would you choose?

Horner: A little one. A little plant-eater.

LiveScience: No T. rex for you?

Horner: Would you make something that would turn around and eat you? Sixth-graders would do that, but I'd just as soon make something that wouldn't eat me. And you could have it as a pet without worrying about it eating the rest of your pets.

source

Source:LiveScience

Merry Christmas from Penguinology!

2011-12-24T22:10:00.001-08:00

Wishing that all your dreams will come true this year at Christms!

~~~wiinterrr

Do penguins communicate under water?

2011-12-24T11:06:00.000-08:00

Do penguins communicate under water?

Written by Chris Thomas

Friday, 23 December 2011

“Very little is known about underwater acoustic communication in birds so any findings are important.”—Dr Parsons. Flickr: Andy Field

IT’S a question being asked by the Centre for Marine Science and Technology’s Research Fellow Miles Parsons, who is collaborating with Perth Zoo to find out.

While penguins can be noisy on land, Dr Parsons says research into the sounds they make, if any, underwater has been extremely limited.

“Given some species of penguins spend significant time underwater and dive to depths where visual communication is reduced, it’s feasible that sound provides an alternative source of communication,” Dr Parsons says.
“The reasons behind any communication could be identifying, locating and catching food, warning signals, exploration, socialising and being antagonistic—but at the moment this is speculation.”

As part of his research Dr Parsons placed underwater noise loggers that include a hydrophone or underwater microphone, hard drive and battery pack, in Perth Zoo’s fairy penguin (Eudyptula minor novaehollandiae) enclosure.

The devices recorded all noise for nine out of every 15 minutes.

“If the penguins produce any sounds underwater we will be able to record them,” Dr Parsons says.
“From there, we would be able to investigate whether these sounds are used to communicate between the penguins or if they serve some other function (involuntary noise).

“Very little is known about underwater acoustic communication in birds so any findings are important.”
Dr Parsons says his research is in a controlled zoo environment and communication in the wild may be different.

Environmental noise could also affect penguin sounds and its perception underwater.

“There’s a lot of possible ways ambient, whether a biotic or man-made, noise can affect the sound production, transmission and reception,” he says.

“These can range from a behavioral change in the penguins with a disturbance causing movement away from the noise source and a reduced production of sound by penguins.”

“There’s also the masking of calls—ambient noise at the same frequency as any penguin calls will reduce the range at which a recipient can detect a call, or possibly the sound of an approaching predator.

“Particularly intense signals may cause temporary or permanent damage to the hearing.”

Perth Zoo’s penguin colony has been transferred to Melbourne Zoo while renovations take place and is due back before Christmas.

“What I am hoping to do is re-record when the penguins return from Melbourne and they re-acquaint themselves with their environment,” Dr Parsons says,

“Then we might hear some communication.”

source

Dinosaurs With Killer Claws Yield New Theory About Evolution of Flight

2011-12-16T05:53:00.000-08:00

New research from Montana State University reveals how dinosaurs like Velociraptor and Deinonychus used their famous killer claws, leading to a new hypothesis on the evolution of flight in birds. (Credit: Illustration by Nate Carroll)

ScienceDaily (Dec. 14, 2011) — New research from Montana State University's Museum of the Rockies has revealed how dinosaurs like Velociraptor and Deinonychus used their famous killer claws, leading to a new hypothesis on the evolution of flight in birds.

In a paper published Dec. 14 in PLoS ONE, MSU researchers Denver W. Fowler, Elizabeth A. Freedman, John B. Scannella and Robert E. Kambic (now at Brown University in Rhode Island), describe how comparing modern birds of prey helped develop a new behavior model for sickle-clawed carnivorous dinosaurs like Velociraptor.

"This study is a real game-changer," said lead author Fowler. "It completely overhauls our perception of these little predatory dinosaurs, changing the way we think about their ecology and evolution."

The study focuses on dromaeosaurids; a group of small predatory dinosaurs that include the famous Velociraptor and its larger relative, Deinonychus. Dromaeosaurids are closely related to birds, and are most famous for possessing an enlarged sickle-claw on digit two (inside toe) of the foot. Previous researchers suggested that this claw was used to slash at prey, or help climb up their hides, but the new study proposes a different behavior.

"Modern hawks and eagles possess a similar enlarged claw on their digit 2's, something that hadn't been noted before we published on it back in 2009," Fowler said. "We showed that the enlarged D-2 claws are used as anchors, latching into the prey, preventing their escape. We interpret the sickle claw of dromaeosaurids as having evolved to do the same thing: latching in, and holding on."

As in modern birds of prey, precise use of the claw is related to relative prey size.

"This strategy is only really needed for prey that are about the same size as the predator; large enough that they might struggle and escape from the feet," Fowler said. "Smaller prey are just squeezed to death, but with large prey all the predator can do is hold on and stop it from escaping, then basically just eat it alive. Dromaeosaurs lack any obvious adaptations for dispatching their victims, so just like hawks and eagles, they probably ate their prey alive too."

Other features of bird of prey feet gave clues as to the functional anatomy of their ancient relatives; toe proportions of dromaeosaurids seemed more suited for grasping than running, and the metatarsus (bones between the ankles and the toes) is more adapted for strength than speed.

"Unlike humans, most dinosaurs and birds only walk on their toes, so the metatarsus forms part of the leg itself," Fowler said. "A long metatarsus lets you take bigger strides to run faster; but in dromaeosaurids, the metatarsus is very short, which is odd."

Fowler thinks that this indicates that Velociraptor and its kin were adapted for a strategy other than simply running after prey.

"When we look at modern birds of prey, a relatively short metatarsus is one feature that gives the bird additional strength in its feet," Fowler continued. "Velociraptor and Deinonychus also have a very short, stout metatarsus, suggesting that they had great strength but wouldn't have been very fast runners."

The ecological implications become especially interesting when dromaeosaurids are contrasted with their closest relatives: a very similar group of small carnivorous dinosaurs called troodontids, Fowler said.

"Troodontids and dromaeosaurids started out looking very similar, but over about 60 million years they evolved in opposite directions, adapting to different niches," Fowler said. "Dromaeosaurids evolved towards stronger, slower feet; suggesting a stealthy ambush predatory strategy, adapted for relatively large prey. By contrast, troodontids evolved a longer metatarsus for speed and a more precise, but weaker grip, suggesting they were swift but probably took relatively smaller prey."

The study also has implications for the next closest relatives of troodontids and dromaeosaurids: birds. An important step in the origin of modern birds was the evolution of the perching foot.

"A grasping foot is present in the closest relatives of birds, but also in the earliest birds like Archaeopteryx," Fowler said. "We suggest that this originally evolved for predation, but would also have been available for use in perching. This is what we call 'exaptation:' a structure evolved originally for one purpose that can later be appropriated for a different use."

The new study proposes that a similar mechanism may be responsible for the evolution of flight.

"When a modern hawk has latched its enlarged claws into its prey, it can no longer use the feet for stabilization and positioning," Fowler said. "Instead the predator flaps its wings so that the prey stays underneath its feet, where it can be pinned down by the predator's bodyweight."

The researchers suggest that this 'stability flapping' uses less energy than flight, making it an intermediate flapping behavior that may be key to understanding how flight evolved.

"The predator's flapping just maintains its position, and does not need to be as powerful or vigorous as full flight would require. Get on top, stay on top; it's not trying to fly away," Fowler said. "We see fully formed wings in exquisitely preserved dromaeosaurid fossils, and from biomechanical studies we can show that they were also able to perform a rudimentary flapping stroke. Most researchers think that they weren't powerful enough to fly; we propose that the less demanding stability flapping would be a viable use for such a wing, and this behavior would be consistent with the unusual adaptations of the feet."

Another group of researchers has proposed that understanding flapping behaviors is key to understanding the evolution of flight, a view with which Fowler agrees.

"If we look at modern birds, we see flapping being used for all sorts of behaviors outside of flight. In our paper, we are formally proposing the 'flapping first' model: where flapping evolved for other behaviors first, and was only later exapted for flight by birds."

The researchers believe their new ideas will open multiple new lines of investigation into dinosaur paleobiology, and the evolution of novel anatomical structures.

"As with other research conducted at the Jack Horner paleo lab, we're looking at old paleontological questions with a fresh perspective, taking a different angle," Fowler said. "Just as you have to get beyond the idea that feet are used just for walking, so we are coming to realize that many unusual structures in modern animals originally evolved for quite different purposes. Revealing the selection pathways that mold and produce these structures helps us to better understand the major evolutionary transitions that shaped life on this planet."

Story Source:

The above story is reprinted from materials provided by Montana State University.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

Denver W. Fowler, Elizabeth A. Freedman, John B. Scannella, Robert E. Kambic. The Predatory Ecology of Deinonychus and the Origin of Flapping in Birds. PLoS ONE, 2011; 6 (12): e28964 DOI: 10.1371/journal.pone.0028964

Montana State University (2011, December 14). Dinosaurs with killer claws yield new theory about evolution of flight. ScienceDaily. Retrieved December 16, 2011, from http://www.sciencedaily.com /releases/2011/12/111214171541.htm

100 years on, Antarctic science going strong

2011-12-15T09:27:00.000-08:00

It's one of the primary drivers of human activity on the continent

Jefferson Beck / NASA

A NASA aircraft, part of the agency's IceBridge mission, banks over an ice shelf jutting out from western Antarctica during an October 2011 data-gathering flight.

By Andrea Mustain

OurAmazingPlanet

12/14/2011

eek, dozens of brave revelers — the prime minister of Norway among them — are converging on the South Pole to celebrate the historic trek of Norwegian explorer Roald Amundsen, the first human to set foot there on Dec. 14, 1911.

Yet in an ironic twist, some might argue that it is the runner-up in the grueling contest whose legacy has proved more lasting.

British explorer Robert Falcon Scott, who reached the pole a month after Amundsen, died on his return march, unable to escape the tightening noose of the Antarctic winter. And although his oft-maligned tactics proved, in part, to be his undoing, Scott's insistence on bringing scientists on his expedition — at great cost to himself — helped spark a tradition of scientific inquiry in Antarctica that endures to this day, according to Ross MacPhee, curator at the American Museum of Natural History in New York, and author of the book, "Race to The End: Amundsen, Scott, and the Attainment of the South Pole" (Sterling Innovation, 2010).
"Every scientist working in Antarctica today owes Scott something," MacPhee told OurAmazingPlanet in September.

Science is now one of the primary drivers of human activity on the continent.
Each year, when the perpetual daylight of austral summer begins, droves of scientists descend on Antarctica to study its biology, drill deep into its ice, and send airplanes soaring overhead to image what lies underneath its glaciers.
Nearly 30 countries operate more than 80 research stations around the continent, according to 2009 numbers from the Council of Managers of National Antarctic Programs.
A flurry of work is now under way on and around the continent.

Courtesy of Charles Leski, Leski Auctions.

Robert Falcon Scott in the expedition's well-stocked hut.

Charismatic fauna

Some scientists come to study the unique crowds of marine life that gather near the nutrient-rich waters off the Antarctic coast in the comparatively balmy summer. Penguins may be the most beloved of the local animal pantheon, but studying these birds is nothing like a Disney movie.
"Penguins are not cuddly at all. They're really very strong and very feisty, and they don't like to be picked up, which we try not to do," said David Ainley, a marine ecologist who has been studying Adélie penguins in Antarctica since the late 1960s.

For decades, Ainley, now with the California-based ecological consulting firm H.T. Harvey & Associates, has researched why penguin populations are changing; some colonies have grown, others have shrunk. He said he's interested in answering a very basic question about life on our planet — how do animals cope with their environment? — and that penguins are the ideal research subject.
"They're fairly large so you can put instruments on them and record their behavior," Ainley told OurAmazingPlanet just hours before he boarded a plane headed south.

Dr. Robert Ricker, NOAA / NOS / ORR

Don't ask these guys to tap dance. Adelie penguins in Antarctica.

In addition, he said, they're pretty easy to find. "Penguins are very visible," Ainley said. "In the Antarctic they don't have any place to hide. They don't live in burrows, and it's daylight all the time."

Biological time trip

While Ainley and his team spend their days on the rocky slopes of Antarctic islands, other scientists spend the austral summer on ships. David Barnes, with the British Antarctic Survey, spoke with OurAmazingPlanet from the RRS James Ross, a research vessel parked near the Antarctic Peninsula, the long finger of land that points toward South America.

Barnes said that his research focuses on trying to unlock the secrets of Antarctica's icy past, specifically how the reach of the massive West Antarctic Ice Sheet has changed from age to age. Scientists know it has been larger than it is now, and some suspect it has been smaller than it is now, but anything more exact is difficult to pin down.

"The problem is that every time there's an ice age it's wiped out everything — so we don't really know where the last ice sheet got to," Barnes said. But there is another way to peek into the Antarctic's past: "Where we can't get good signals from glaciology or geology, biology has a cunning way of stepping in," he said.

Eric Rignot, JPL

This is an aerial, close-up view of the floating section and ice front of Pine Island glacier, November 2002.

Barnes looks at the genetic makeup of sea creatures around western Antarctica to determine how long populations have been isolated from one another by the ice.
"Genetics preserve a connection between species and populations, so by looking around Antarctica at various depths we can get an idea of whether that area used to be underneath an ice sheet," Barnes said.
That information can, in turn, help scientists figure out how the West Antarctic Ice Sheet behaved in climates past, and how it might behave in our warming world.

Ice life

Still other scientists will spend the austral summer living on the ice itself. Robert Bindschadler, a glaciologist and scientist emeritus with NASA, along with a small team of researchers, will spend six weeks sleeping in small tents on a floating plain of ice — the Pine Island Glacier ice shelf — the outlet of one of the largest and fastest moving glaciers in Antarctica.
Ice shelves, which ring the continent, appear to be a key player in the increasing and alarming rate at which glaciers in the West Antarctic Ice Sheet are melting and raising sea levels in recent years, Bindschadler said. But getting direct observations of how this is happening is a challenge. Satellite imaging and data provide some details, but the continent is remote, and its long, brutal winter permits scientists to work there for only about three months a year, [ Stunning Photos of Antarctic Ice ]

Observations indicate that comparatively warm ocean water is lapping away at the ice shelves, which, as they weaken, allow glaciers to slide into the sea at a faster and faster clip — yet the direct mechanisms remain hidden from view.
"Satellites have taken us really far, but they can't give us the answers to what's going on underneath," Bindschadler said. To that end, his team will spend its days drilling several holes through nearly a third of a mile (500 meters) of ice to drop sensors into the sea below to measure variations in temperature and currents.
Some scientists conduct their research from the air, working aboard planes equipped with imaging technology that can peer beneath the ice. NASA's IceBridge project focuses on the western half of the continent, while other international collaborations focus on the far larger yet more stable eastern half.

Ice work if you can get it

Other research must be done on the ground. Scientists are drilling deep into the ice to collect signatures of past climate trapped inside, or looking for microbes that dwell in it. The race to drill down to the more than 200 freshwater lakes that pepper the continent is another tantalizing quest..

Some researchers work in Antarctica because the frigid continent, free of a native human population or meddling flora and fauna, provides a kind of natural laboratory.
"In most ecosystems you have plants all over the place, and they do a lot of things to complicate the system," said Byron Adams, a professor at Brigham Young University who studies the nematodes and other tiny creatures that are found in the few patches of ice-free soil in the Antarctic.

Rob Jones, National Science Foundation

Flags fly outside McMurdo Station, one of three United States research stations in Antarctica and the largest.

Still other researchers take advantage of the high altitude and clear air to peer through telescopes into distant space and the early universe.
At about 1.5 times the size of the United States, Antarctica has plenty of scientific real estate to go around.
At the heart of much of the research is the question of how the continent's ice is responding to climate change. Antarctica is home to some of the most dramatic effects of climate change seen anywhere on Earth, from melting glaciers to increasing winds to warming temperatures. The Antarctic Peninsula has warmed several times faster than the global average rate.

"We're asking really fundamental questions about how ecosystems respond to a changing climate, and ultimately the goal is to be able to make predictions about this," Adams told OurAmazingPlanet.
Despite the challenges — bone-chilling winds, constant sunlight, extreme isolation and ever-changing weather — many scientists said working in Antarctica is worth the hardship and the long hours spent packing as much work into an expedition as possible. Although it's not for everyone, they cautioned, the work can be deeply satisfying, breeding a sense of camaraderie that can last a lifetime.

"When you're out in the deep field, and you're only living with what you brought, and the plane turns and leaves, that's the Antarctica I prefer," Bindschadler said. "You really are in a different world."

source

Seabirds: Climate Differences Have Less Impact On Transmission of Blood Parasites Than Expected

2011-12-15T09:12:00.000-08:00

Close neighbourly relations: Like these gentoo penguins on the Falkland Islands, seabirds often breed in dense colonies. The very conditions that provide the birds with protection against predators, promote the spread of ticks and other bloodsuckers which can transmit diseases. This population was found to be free of blood parasites, however. (Credit: © MPI for Ornithology)

ScienceDaily (Dec. 12, 2011) — Seabirds often live in large colonies in very confined spaces. Parasites, such as fleas and ticks, take advantage of this ideal habitat with its rich supply of nutrition. As a result, they can transmit blood parasites like avian malaria to the birds. Scientists from the Max Planck Institute for Ornithology in Radolfzell and a team of international colleagues have investigated whether this affects all seabirds equally, and whether climate conditions, the habitat or particular living conditions influence infection with avian malaria. They discovered that most seabirds are free of malaria parasites; however, some groups, especially frigatebirds, are particularly common hosts to malaria parasites.

Although there is a link between warmer temperatures and increased rates of infection, not all tropical seabirds are infected. The risk of infection within a habitat increases for species with longer fledgling periods and specific types of breeding grounds.

Seabirds exist in locations as varied as the Antarctic and tropical oceans. However, they all need land for breeding grounds. In order to protect themselves against predators or due to a lack of suitable breeding places, they often form large dense colonies. As a result, they provide blood suckers like fleas, ticks and bird lice -- wingless insects which live in the plumage and feed on the birds' feathers and blood -- with a plentiful supply of food and a habitat. Therefore, these insects can arise in large numbers in such colonies. These small pests also survive well in cold climates such as that found in the Subantarctic, and are not particularly specialised in their choice of food, something the researchers know from their own painful experience.

Other blood-sucking insects, like mosquitoes, are present mainly in warmer climates, as found in the tropical breeding grounds. Because mosquitoes are among the main transmitters of the Plasmodium genus of avian malaria, the researchers from the Max Planck Institute for Ornithology and their colleagues from Spain, France, Mexico and the US investigated whether infections of avian malaria differed in seabirds from cold and warm marine areas. To do this, they analysed blood samples from seabirds from different regions for parasitic infections using genetic methods.

"We were surprised that the climate differences had less impact on the transmission of blood parasites than expected," says Petra Quillfeldt. "More vectors live in warmer climates; therefore, we would have expected to find a higher rate of infection in tropical locations. We discovered, however, that different species living on the same island under the same climate conditions can display very different rates of infection." The researchers defined several seabird groups that regularly carry malaria parasites. Frigatebirds were found to be particularly affected here, as all five species of this tropical seabird family are frequently infected.

"Of five seabird species present in the seabird community on Christmas Island in the tropical Indian Ocean, only the Christmas Island frigatebirds were found to be malaria hosts. Over half of the island's frigatebirds were affected and, moreover, with three genetically different malaria lines of the subgenera Haemoproteus and Parahaemoproteus, one of which was a completely new strain. As opposed to this, tropical birds and three species of gannet on the same island were not infected at all," explains Petra Quillfeldt.

Furthermore, the scientists have failed to find any blood parasite infections in other seabird groups, such as skuas and auks. Their research has led to the conclusion that the likelihood of infection depends, among other things, on the lifestyle of the birds: species with longer fledgling periods and hole-nesters are particularly severely affected.

This is the first study of this kind to examine seabirds in all climate zones. It has shown that different factors can influence infection with malaria parasites. The study also raised new questions: The researchers would now like to gain a better understanding of the life cycles of the malaria parasites and their transmitters, as well as discover which mechanisms are responsible for susceptibility to infection among the different species.

Story Source:

The above story is reprinted from materials provided by Max-Planck-Gesellschaft.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal References:

Petra Quillfeldt, Elena Arriero, Javier Martínez, Juan F Masello, Santiago Merino. Prevalence of blood parasites in seabirds - a review. Frontiers in Zoology, 2011; 8 (1): 26 DOI: 10.1186/1742-9994-8-26
Merino, S., Hennicke, J., Martínez, J., Ludynia, K., Masello, J.F. & Quillfeldt, P. Infection by Haemoproteus parasites in four species of frigatebirds and description of Haemoproteus (Parahaemoproteus) valkiūnasi sp. nov. (Haemosporida, Haemoproteidae). Journal of Parasitology, 2011 Oct 12

Max-Planck-Gesellschaft (2011, December 12). Seabirds: Climate differences have less impact on transmission of blood parasites than expected. ScienceDaily. Retrieved December 15, 2011, from http://www.sciencedaily.com /releases/2011/12/111212092655.htm

Antarctic study digs for clues to penguin past

2011-12-14T06:42:00.000-08:00

By James Borrowdale

Wednesday Dec 14, 2011

Photo / James Borrowdale

Adelie penguins live in the coldest environment on earth.

Happy Feet's distant relatives might one day become victims of climate change.
Experts warn the effects of a warming climate could affect the small ecological niche in which Adelie penguins reside.
Scientists from the University of Auckland and Italy's University of Pisa are in Antarctica to search for clues about Adelie penguins' evolutionary past, and what this reveals about how they will respond to climate change.

Professor Carlo Baroni, professor of geomorphology at the University of Pisa, said penguins lived in the coldest environment on earth and if the temperature warmed, penguins couldn't migrate to a colder climate.
"If global warming increases and affects the Antarctic regions, penguins have no other place to go, so they must adapt or die."
The team left Scott Base this week for a month of collecting samples from two penguin rookeries. Over many years of habitation Adelie penguins leave layers of accumulated bones, eggshells, feathers, nests, and guano. This presents scientists with the opportunity to dig through the levels and gather DNA from long-dead penguins.

"It is very similar to an archaeological approach. We mark squares of one metre by one metre then layer by layer we excavate it and collect samples."
Professor Baroni, now on his 14th trip to Antarctica, said his team had previously uncovered samples as old as 40,000 years.
"We are at the limits of the capability of radiocarbon dating."
Auckland University's Yvette Wharton said the limited ecological niche of Adelie penguins made them excellent subjects for studying adaptive evolution. As their niche changed, she said, the penguins would have to change with it.

"As we are getting climate change occurring there is going to be quite a specific effect on their potential ecological niche. We're squishing them."
She said they would learn of past climatic changes, how the colony sizes had changed, and how the penguins had evolved to meet these new conditions.
"You can then use that as a model to see the types of things that might happen to an organism with environmental changes."

ADELIE PENGUINS

* Males and females come on land for just a few months each summer to breed and raise their chicks - a task mastered by "tag-team parenting" in minding the egg.
* Males arrive first to find the best spot and build a nest. When the females arrive, the males serenade their prospective mates with a sound described as a cross between a donkey and a stalled car.
* Females look for the fattest male they can find, as their partner must spend the first two weeks sitting on the eggs without any chance to go in search of food.

source

How penguins 'time' a deep dive

2011-12-09T11:38:00.001-08:00

8 December 2011

The penguins beat their wings an average of 237 times on each dive

Emperor penguins "time" their dives by the number of flaps they can manage with their wings.

This is according to a new study published in the Journal of Experimental Biology.

It aimed to show how the birds reached the "decision" that it was time to stop feeding and return to the surface to breathe.

Tracking the birds revealed that they flapped their wings, on average, 237 times on each dive.

The study was led by Dr Kozue Shiomi, from the University of Tokyo, Japan.

Dr Shiomi and his team think that the penguins' decision to end their foraging dive and return to the surface is constrained by how much power their muscles can produce after every pre-dive breath. This "flying" motion propels the birds forwards, allowing them to swim quickly through the water, gulping fish.

Using data collected from diving penguins on previous field trips, the team analysed the patterns of more than 15,000 penguin dives.
They studied 10 free-ranging birds and three birds that were foraging through a hole in the ice.

EMPEROR PENGUIN FACTS

Emperor penguins are the largest species of penguin, standing at over one metre tall and weighing an average of 40kg
In the bitter cold, males and females choose mates relatively quickly, pairing off and "flirting" with special neck-stretching displays
The males incubate eggs through the fierce Antarctic winter while females feed themselves up to provide for their chicks in the spring

Timing the penguins' dives revealed that free-ranging birds began their final ascent to the surface about 5.7 minutes into their dive. But penguins diving through the ice hole often dived for longer before performing a U-turn and returning up through the same ice hole.

Examining the acceleration patterns of the penguins as they dived, the team managed to calculate that all the birds used, on average, 237 wing flaps before starting their ascent.

"We suggest", the team concluded in their paper, "that the decision [to return] was constrained not by elapsed time, but by the number of strokes and, thus, perhaps cumulative muscle work."

source

The Realm of the Red Penguin: Peru's Dead Sea of Fossils

2011-11-04T17:20:00.000-07:00

By Lucien Chauvin / Ocucaje Thursday, Nov. 03, 2011

A researcher for Peru's Natural History Museum rests next to the fossilized skeleton of an ancient seal in the Ocucaje Desert in Ica, Peru.

Moises Saman / The New York Times / Redux

Roberto Penny Cabrera is a former officer in the Peruvian Navy and still loves the sea, but the ocean that now captures his attention is not wet. In fact, it has been one of the driest places on earth for millions of years.

Penny, 55, is a self-trained authority on a strip of Peru's coastal desert in Ica, 180 miles south of the capital, Lima. The desert was once a shallow sea with abundant marine life, but that ended when the Andes Mountains surged upward. The resulting cataclysm created what is the world's largest cemetery of marine fossils, many poking out of the white sand.

What sets this stretch of Ica desert apart from similar areas is the preservation of more than bone. The discovery last year of a 5-ft.-tall penguin included the first evidence of preserved scales and feathers, letting experts know that the big bird was red instead of black and white like today's smaller version. It died about 36 million years ago. Also recently discovered in this windswept, rolling desert was the skull of a giant whale, dubbed Leviathan melvillei in honor of Moby Dick's creator. The whale stretched nearly 60 ft. and is believed to have fed on other whales. Its jaw is similar to that of modern-day sharks, with rows of top and bottom teeth.

Penny, who calls himself a "finder," said, "It is amazing to see what the ocean was like millions of years ago. I am not a paleontologist, but you don't have to have a degree to know that what we have here can tell us how the ocean worked." He may not have a title, but Penny has the desert in his blood. One of his distant relatives founded the city of Ica in the mid-16th century, and the family has been there since. He first wandered into the desert as a boy, when his parents would take him to a nearby oasis, Huacachina. "We would go to Huacachina, but I was interested in the surrounding desert. It is where I feel free," he said. Those early family excursions turned into a lifelong obsession with Peru's dead sea

Penny's quest today is to protect the desert, not only safeguarding marine fossils but also burial grounds of Nazca and Paracas cultures, which date back more than 2,000 years, and the area's stunning landscape of ancient seabeds and towering, windblown dunes.

It is an uphill battle.

The rolling dunes around Ocucaje, a small town that serves as a gateway to the desert and lends the arid strip its name, are strewn with skeletons tossed aside by looters digging through burial grounds in search of pottery and world-renowned Paracas textiles. Fossil hunters have chipped away at whale skeletons and decimated shell beds looking for the prized teeth of the megalodon (literally "giant tooth"), giant sharks that once prowled here. "The principal problem in Ocucaje right now is the illegal collection of fossils for scientific or commercial purposes," said José Apolín, a specialist at Peru's Culture Ministry, which just celebrated its first anniversary.

But there is also a problem with control. Apolín, who is technically a biologist, is the only paleontological specialist in the ministry, and he is in the unit in charge of preventing theft and controlling items that are seized. In 2010, his first year on the job, police at the international airport in Lima seized 1,962 cultural items protected by law. Fossils accounted for 1,712 of the items seized.

Even if there were many more employees like Apolín, the law protecting cultural heritage is vague when it comes to fossils. "Fossils are in a kind of legal limbo in Peru. There are gaps in the law because there are people who do not want to include fossils as cultural heritage, because they have not been made by human hand," said Blanca Alva, director of the prevention office.

The ministry has an archaeological division, but there is no paleontology division. Paleontology falls to a unit of the Energy and Mines Ministry. Still, the Culture Ministry is getting ready in the next few weeks to declare Peru's first protected paleontological site. The area, known as the Inga Bridge, is a small site located just outside Lima. Apolín said it will be the first of its kind among 13,000 protected sites nationwide.

While Penny bristles with anger at fossil hunters digging through the desert to pull out what they can sell, he gets even more worked up about authorities, who he says have done nothing to stop it. He says their inaction makes them complicit. Penny gets madder still when he is lumped in with the fossil traffickers — Apolín points to video of Penny handling fossils — because of a small, bizarre collection, including shark teeth, in a single room he calls home in the old family mansion that has seen much better days. Under Peruvian law, the country's treasures, whether fossils or golden objects looted from tombs, can be held in personal collections. It is only illegal to remove them from the country.

"I have never sold a fossil, and what I have, I have found on the desert floor," he said. "There are amazing things out there, but if I tell anyone, they will be lost." Driving a specially equipped truck that lets him roam the desert, Penny is careful to cover his tracks. He continuously doubles back and drives in circles at times to throw others off his trail, fearful that fossil scavengers will follow him to his sacred spots.

Regional tourism authorities would like to promote the desert but worry that a flood of people could mean rampant destruction. "There is an entire desert with a massive amount of fossils. The desert is an attraction that we cannot promote, because large fossils are being taken away and no one is doing anything to stop it," said Elard Roca of the government's local tourism bureau.

Penny's solution is to declare the desert a protected area, but conservationists say the move would be impractical. Pedro Solano, who runs the conservation program for the Peruvian Environmental Law Society, one of the country's leading environmental groups, said that while there are important fossilized remains in the desert, "it would be wrong to say the entire area holds fossils and should be set aside. These kinds of generalization usually cause problems," he said.

Trying to guard the area is also nearly impossible because of its size. The area that contains fossil remains is about 180 miles long and 40 miles wide. The giant penguin was found in the northern reaches, while the whale skeletons are found from Ocucaje south. The Ocucaje stretch is about one-quarter of the total area. Solano said the goal for the desert "should not be to keep people out but manage the spaces for education and research to demonstrate its value as a resource." The Culture Ministry's Apolín said the best way to protect the area is "guaranteeing that fossils are not taken from the country. If we can improve control of fossils trafficking at the airport and ports, we would protect the site."

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Archaeopteryx was first bird after all

2011-10-30T21:25:00.000-07:00

October 26, 2011 Enlarge

Archaeopteryx fossil (Creative Commons - Wikipedia)

(PhysOrg.com) -- The crown of the famous 150-million-year-old Archaeopteryx fossil as the first bird has been restored by a new evolutionary tree.

In a study published today in the journal Biology Letters, Australian researchers say the feathered fossil is indeed of the first known bird, despite another study earlier this year suggesting otherwise.

Archaeopteryx had been considered for 150 years to be the first known bird since the first complete specimen was found in Germany in 1861, revealing a combination of reptilian and and bird features. But Chinese researchers asserted recently that a new and closely related fossil, Xiaotingia zhengi, was a bird-like dinosaur - therefore suggesting that Archaeopteryx was also a dinosaur.

However, the new study, led by Dr Michael Lee, of the South Australian Museum, used a more detailed analyis to show that Archaeopteryx was a bird.

"Archaeopteryx is iconic in palaeontology as the basal bird, however the plethora of discoveries of feathered dinosaurs in China, in particular, has progressively eroded the distinction of just what defines a bird," says one of the authors, Dr Trevor Worthy, a palaeontologist in the UNSW School of Biological, Earth and Environmental Sciences.

"This trend came to a head when Xaiotingia was analysed most recently and in the analysis presented Archaeopteryx was found to jump ship as it were from the birds to the dromaeosaurs.

"This sensational result was presented and attracted much publicity, but the very weak statistical support for this new relationship was not given due consideration.

"In our work, Mike Lee has shown quite clearly that methodology is highly significant and that before a paradigm is overturned data needs to be rigorously examined.

"Using a different analytical methodology than that usually used by morphologists, but one always used by analysts of molecular data, we found that Archaeopteryx remains the basal bird and does so with strong statistical support.

"This case demonstrates that multiple analysis methods should be used, each with concordant results before a paradigm breaking result is accepted. And it shows that Archaeopteryx remains the key to understanding the origin of birds."

More information: http://rsbl.royals … tent/current
Provided by University of New South Wales

source

Which NZ coastal species really are native?

2011-10-17T09:56:00.000-07:00

By John Gibb on Mon, 17 Oct 2011

Prof Jon Waters takes a close look at a stuffed yellow-eyed penguin at the Otago Museum. Photo: Peter McIntosh

It has been third time lucky for University of Otago zoologist Prof Jonathan Waters as he starts investigating whether some of our native coastal species, including the yellow-eyed penguin, really are native. Prof Waters said it was "great" that an $878,000 grant which he had recently received from the Marsden Fund would enable him to investigate how animals responded to human impacts, and how many of New Zealand's coastal species were actually new arrivals from overseas.
Yellow-eyed penguins, for instance, apparently arrived in New Zealand only in the past 500 years, replacing a prehistoric penguin species, the waitaha, that was wiped out shortly after human settlement, he said.
One of his former Otago PhD students, Dr Sanne Boessenkool, undertook earlier research several years ago and discovered remains of the extinct waitaha penguin.
It is suggested that some yellow-eyed penguins made their way north from their native Auckland Islands and Campbell Island and later established themselves on the Otago Peninsula and elsewhere on the Otago coast after the waitaha penguin became extinct.
Many people would be surprised the yellow-eyed penguin may not have been living in Otago as long as previously believed, he said.
"We tend to think that things that are here now are things that have been here for a long time," Prof Waters said.
The kind of extinction-recolonisation events apparently involved with such penguins may be the rule rather than the exception in coastal New Zealand, including with sea-lions and little blue penguins, he said.
It was "great" to be able to pursue the research, after two earlier recent attempts to gain Marsden funding for the project had been unsuccessful.
The little blue penguins which had now established themselves on the Otago coast, after earlier being largely wiped out by humans, were in fact penguins from Australia.
They were different from endemic little blue penguins found elsewhere on the New Zealand mainland.
New Zealand sea lions found on the Otago coast were also not the same creatures that once previously existed there, but were apparently a replacement population from the subantarctic islands, researchers said.
Collaborators in the project are Prof Lisa Matisoo-Smith, of the Otago anatomy department, and Dr Paul Scofield, of the Canterbury Museum.
The researchers will use carbon dating and state-of-the-art DNA analysis of prehistoric bones to shed further light on the country's "dramatic biological history", and to conduct a biological audit of prehistoric New Zealand.
Archaeologists would be teaming up with geneticists, in order to "reveal exciting aspects of New Zealand's past - stories that were previously impossible to tell," he said.

Source

Pigeon 'Milk' Contains Antioxidants and Immune-Enhancing Proteins

2011-09-28T14:09:00.000-07:00

Pigeon and chick. (Credit: Dr. Tamsyn Crow

ScienceDaily (Sep. 28, 2011) — Production of crop milk, a secretion from the crops of parent birds, is rare among birds and, apart from pigeons, is only found in flamingos and male emperor penguins. Essential for the growth and development of the young pigeon squab, pigeon 'milk' is produced by both parents from fluid-filled cells lining the crop that are rich in fat and protein.

Research published in BioMed Central's open access journal BMC Genomics uses new technology to study the genes and proteins involved in pigeon 'milk' production and shows that pigeon 'milk' contains antioxidants and immune-enhancing proteins.

Researchers from CSIRO Livestock Industries and Deakin University, Australia, compared the global gene expression profiles of the crops of four 'lactating' and four 'non-lactating' female pigeons. As the pigeon genome has not yet been sequenced, they used a chicken microarray to find the genes involved. Genes predominantly over-expressed in 'lactating' birds were those involved in stimulating cell growth, producing antioxidants and in immune response. They also found genes associated with triglyceride fat production, suggesting the fat in the 'milk' is derived from the pigeon's liver.

Lead author, Meagan Gillespie, says, "It is possible that if antioxidant and immune proteins are present in pigeon 'milk', they are directly enhancing the immune system of the developing squab as well as protecting the parental crop tissue." She continues, "This study has provided a snap-shot view of some of the processes occurring when 'lactation' in the pigeon crop is well established. Due to the unusual nature of 'lactation' in the pigeon it would be interesting to investigate the early stages of the differentiation and development of the crop in preparation for 'milk' production to further ascertain gene expression patterns that characterize crop development and 'lactation' in the pigeon."

She concludes, "This mechanism is an interesting example of the evolution of a system with analogies to mammalian lactation, as pigeon 'milk' fulfills a similar function to mammalian milk."

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by BioMed Central, via EurekAlert!, a service of AAAS.

Journal Reference:

Meagan J. Gillespie, Volker R. Haring, Kenneth A. McColl, Paul Monaghan, John A. Donald, Kevin R. Nicholas, Robert J. Moore, Tamsyn M. Crowley. Histological and global gene expression analysis of the 'lactating' pigeon crop. BMC Genomics, 2011; 12: 452 DOI: 10.1186/1471-2164-12-452

BioMed Central (2011, September 28). Pigeon 'milk' contains antioxidants and immune-enhancing proteins. ScienceDaily. Retrieved September 28, 2011, from http://www.sciencedaily.com /releases/2011/09/110919074253.htm

Feathered Friends Are Far from Bird-Brained When Building Nests

2011-09-27T18:00:00.000-07:00

ScienceDaily (Sep. 26, 2011) — Nest-building is not just instinctive but is a skill that birds learn from experience, research suggests.

Scientists filmed male Southern Masked Weaver birds in Botswana as they built multiple nests out of grass during a breeding season. Their findings contrast with the commonly-held assumption among scientists that nest-building is an innate ability.

The researchers found that individual birds varied their technique from one nest to the next. They also saw that some birds build their nests from left to right, and others from right to left.

Also, as the birds gained more experience in building nests, they dropped blades of grass less often, implying that the art of nest building requires learning.

Researchers from the Universities of Edinburgh, St Andrews and Glasgow together with scientists from Botswana say their findings may help to explain how birds approach nest-building and whether they have the mental capacity to learn, or whether their skills are developed through repetition.

Researchers chose the colourful African bird because they build complex nests, which is potentially a sign of intelligence. More importantly, Weaver birds build many nests -- often dozens in a season, allowing the team to monitor differences in nests built by the same bird.

Dr Patrick Walsh of the University of Edinburgh's School of Biological Sciences, who took part in the study, said: "If birds built their nests according to a genetic template, you would expect all birds to build their nests the same way each time. However this was not the case. Southern Masked Weaver birds displayed strong variations in their approach, revealing a clear role for experience. Even for birds, practice makes perfect."

The research was published in the journal Behavioural Processes and was funded by the Leverhume Trust.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of Edinburgh, via EurekAlert!, a service of AAAS.

Journal Reference:

Patrick T. Walsh, Mike Hansell, Wendy D. Borello, Susan D. Healy. Individuality in nest building: Do Southern Masked weaver (Ploceus velatus) males vary in their nest-building behaviour? Behavioural Processes, 2011; 88 (1): 1 DOI: 10.1016/j.beproc.2011.06.011

University of Edinburgh (2011, September 26). Feathered friends are far from bird-brained when building nests. ScienceDaily. Retrieved September 27, 2011, from http://www.sciencedaily.com /releases/2011/09/110925192704.htm

Smells may help birds identify their relatives

2011-09-22T08:36:00.000-07:00

Researchers at U Chicago and the Chicago Zoological Society found in an experiment at Brookfield Zoo that penguins can recognize the smell of familiar locations, something that may guide them back to their mates. The ability is useful as penguins live in large colonies but remain monogamous.

Photos by Jim Schulz/Chicago Zoological Society

Smells may help birds identify their relatives

By William Harms

September 21, 2011

Birds may have a more highly developed sense of smell than researchers previously thought, contend scholars who have found that penguins may use smell to determine if they are related to a potential mate.

The research by the University of Chicago and the Chicago Zoological Society, which manages Brookfield Zoo, shows how related birds are able to recognize each other. The study, published Wednesday, Sept. 21 in the article, “Odor-based Recognition of Familiar and Related Conspecifics: A First Test Conducted on Captive Humboldt Penguins (Spheniscus humboldti)” in the journal PLoS ONE, could help conservationists design programs to help preserve endangered species.

“Smell is likely the primary mechanism for kin recognition to avoid inbreeding within the colony,” said Heather Coffin, lead author of the paper.

Coffin conducted the research while a graduate student at UChicago and was joined in writing the paper by Jill Mateo, associate professor in Comparative Human Development at UChicago, and Jason Watters, director of animal behavior research for the Chicago Zoological Society.

“This is the first study to provide evidence for odor-based kin discrimination in birds,” said Mateo, who is a specialist on kin recognition.

Experts said the work offers important insights into how birds use smell to guide behavior.
“The work by the research group is truly groundbreaking in that it shows for the first time ever in birds how the olfactory sense of captive penguins is both informative and functional in a behaviorally critical context: namely the recognition of friends from foes in general, and relatives from non-relatives in particular,” said Mark E. Hauber, professor of psychology at Hunter College, a specialist on bird social recognition.

Penguins are ideal subjects because they typically live in colonies made up of thousands of birds. They live in monogamous pairs — an arrangement that facilitates rearing of their young, since parents frequently take turns leaving the nest to gather food. Despite the size of the community, mates are able to find each other after traveling for days foraging for food in the ocean.

Research on other sea birds has shown that smell helps guide birds to their home territory and helps them forage for food. Other research has shown that birds could use sound and sight to recognize each other, but no other studies have shown that smell might be used in connection with kin recognition, Mateo said.
In the study conducted at Brookfield Zoo, researchers first sought to determine if the penguins were able to recognize familiar individuals by smell. They constructed an experiment using a dozen penguins, from a group that included breeding pairs, their offspring and nonbreeding individuals. The birds — all Humboldt penguins—endangered natives of Peru—were from groups either on exhibit or off exhibit.

The zoo is an ideal setting for the research, as it has extensive records on which penguins are related and have been housed together, Watters said.

Researchers took odor samples from glands near the penguins’ tails, where an oil that the birds use for preening is secreted. They put the oil on cotton swabs and rubbed the odor inside dog kennels, similar to the enclosures penguins at a zoo use for their nests. They also put the odor on paper coffee filters and placed them under mats inside the kennels.

When the penguins were released to the area containing the kennels, the researchers found that penguins spent more time in the kennels with familiar odors. The penguins were able to distinguish between the odors of birds they spent time with and the odors of unfamiliar penguins.

“What I found particularly notable about the study was that the authors identified the oil secreted from the penguins’ preen gland, which is rubbed on the feathers to make them water repellent, as the odor source used in recognition,” said Bryan D. Neff, professor and associate chairof biology, University of Western Ontario and an expert on kin recognition. “Oils are used in kin recognition by species of other animals, most notably a variety of insect species, including bees and wasps, which when considered with the penguin data provide a wonderful example of convergent evolution.”

“It’s important for birds that live in large groups in the wild, like penguins, to know who their neighbors are so that they can find their nesting areas and also, through experience, know how to get along with the birds nearby,” Watters said.

Because offspring usually return to the same colony for nesting, siblings have the potential of becoming mates, something that can be avoided by their smell mechanism, the new research shows.

Researchers also found that when the birds were exposed to the odors of unfamiliar kin and unfamiliar non-kin, they spent more time in the kennels with odors of unfamiliar non-kin, indicating they were probably able to determine by smell which animals they were related to and were more curious about the novel odors. Being able to make the distinction may help the penguins avoid mating with kin, researchers said. The discovery also could assist zoos in managing their breeding programs.

“It could also be true that birds do a better job determining who potential mates are than do people in zoos, who spend a great deal of time lining up the appropriate matches,” Watters said.

The ability of birds to be able to recognize familiar scents and thus be guided to their home territory also has potential value to naturalists, he said. “You could imagine that if you were trying to reintroduce birds to an area, you could first treat the area with an odor the birds were familiar with. That would make them more likely to stay.

source

Primitive Birds Shared Dinosaurs' Fate

2011-09-21T17:49:00.000-07:00

The bones are from the 17 species of Cretaceous birds which went extinct around the time of the dinosaurs. The two on the far left are foot bones and the rest are shoulder bones. (Credit: Courtesy Yale University)

ScienceDaily (Sep. 21, 2011) — A new study puts an end to the longstanding debate about how archaic birds went extinct, suggesting they were virtually wiped out by the same meteorite impact that put an end to dinosaurs 65 million years ago.

For decades, scientists have debated whether birds from the Cretaceous period -- which are very different from today's modern bird species -- died out slowly or were killed suddenly by the Chicxulub meteorite. The uncertainty was due in part to the fact that very few fossil birds from the end of this era have been discovered.

Now a team of paleontologists led by Yale researcher Nicholas Longrich has provided clear evidence that many primitive bird species survived right up until the time of the meteorite impact. They identified and dated a large collection of bird fossils representing a range of different species, many of which were alive within 300,000 years of the impact.

"This proves that these species went extinct very abruptly, in terms of geological time scales," said Longrich. The study appears the week of Sept. 19 in the journal Proceedings of the National Academy of Sciences.
The team examined a large collection of about two dozen bird fossils discovered in North America -- representing a wide range of the species that existed during the Cretaceous -- from the collections of Yale's Peabody Museum of Natural History, the American Museum of Natural History, the University of California Museum of Paleontology, and the Royal Saskatchewan Museum. Fossil birds from the Cretaceous are extremely rare, Longrich said, because bird bones are so light and fragile that they are easily damaged or swept away in streams.

"The birds that had been discovered hadn't really been studied in a rigorous way," Longrich said. "We took a much more detailed look at the relationships between these bones and these birds than anyone had done before."

Longrich believes a small fraction of the Cretaceous bird species survived the impact, giving rise to today's birds. The birds he examined showed much more diversity than had yet been seen in birds from the late Cretaceous, ranging in size from that of a starling up to a small goose. Some had long beaks full of teeth.
Yet modern birds are very different from those that existed during the late Cretaceous, Longrich said. For instance, today's birds have developed a much wider range of specialized features and behaviors, from penguins to hummingbirds to flamingoes, while the primitive birds would have occupied a narrower range of ecological niches.

"The basic bird design was in place, but all of the specialized features developed after the mass extinction, when birds sort of re-evolved with all the diversity they display today," Longrich said. "It's similar to what happened with mammals after the age of the dinosaurs."

Longrich adds that this study is not the first to suggest that archaic birds went extinct abruptly. "There's been growing evidence that these birds were wiped out at the same time as the dinosaurs," Longrich said. "But this new evidence effectively closes the book on the debate."

Other authors of the paper include Tim Tokaryk (Royal Saskatchewan Museum) and Daniel Field (Yale University).

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Yale University.

Journal Reference:

N. R. Longrich, T. Tokaryk, D. J. Field. Mass extinction of birds at the Cretaceous-Paleogene (K-Pg) boundary. Proceedings of the National Academy of Sciences, 2011; 108 (37): 15253 DOI: 10.1073/pnas.1110395108

Yale University (2011, September 21). Primitive birds shared dinosaurs' fate. ScienceDaily. Retrieved September 21, 2011, from http://www.sciencedaily.com /releases/2011/09/110919151315.htm

Trapping time in amber

2011-09-16T16:05:00.000-07:00

By Brian Murphy/September 15, 2011

A feather from the late Cretaceous is trapped in amber.

(Edmonton) Secrets from the age of the dinosaurs are usually revealed by fossilized bones, but a University of Alberta research team has turned up a treasure trove of late Cretaceous feathers, which have been discovered trapped in tree resin.
The resin turned to resilient amber preserving some 80-million-year-old protofeathers, possibly from non-avian dinosaurs, as well as plumage that is very similar to modern birds, including those that can swim under water.

U of A paleontology graduate student Ryan McKellar discovered a wide range of feathers trapped in amber in collections at the Royal Tyrrell Museum and in the private collection of the Leuck family in Medicine Hat.
“Most of the feather specimens were probably blown into contact with the sticky surface of the resin and encapsulated by subsequent resin flows,” said McKellar.
The 11 feather specimens used by the U of A team were all found near the community of Grassy Lake in southern Alberta. The research specimens are described as the richest amber feather find from the late Cretaceous period.

“The amber preserves microscopic detail of the feathers and even their pigment or colour,” said McKellar. “I would describe the colours as typically ranging from brown to black.”
During the late Cretaceous, southern Alberta was a warm coastal region. “The trees that produced the resin were probably comparable to the redwood forests of the Pacific Northwest,” said McKellar.
No dinosaur or avian fossils were found in direct association with the amber feather specimens, but McKellar says comparison between the amber and fossilized feathers found in rock strongly suggest that some of the Grassy Lake specimens are from dinosaurs. The non-avian dinosaur evidence points to small theropods as the source of the feathers.

McKellar says that some of the feather specimens can take on water, enabling the bird to dive more effectively and are very similar to those of modern birds like the Grebe, which are able to swim underwater.
“The preservation of microscopic detail and pigmentation has provided a unique snapshot of feathers and their uses in the late Cretaceous forests of Alberta,” said McKellar.

The U of A team’s research was published Sept. 15, in the journal Science.

source

How penguins find a perfect partner

2011-09-13T08:12:00.001-07:00

King penguin parents spend about 14 months incubating their egg, then rearing their chick. They take it in turns to find food, so the strength of their bond is crucial. Biologists want to know how they make this important mate selection, and even how the birds tell a male from a female; the two sexes look almost identical.

Prof Stephen Dobson from the National Centre for Scientific Research in Montpellier, France, playfully sums up his research: "I'm trying to work out what makes a sexy penguin." His studies of the birds on Kerguelen Island have revealed that penguins often struggle to spot a member of the opposite sex.

Prof Dobson also found that males on the island in the Southern Indian Ocean often had to compete particularly hard to snag a female mate. He and his team noticed that, during mating season, trios of penguins would "parade" around together. DNA analysis showed that the trios were usually two males pursuing a female.

When the penguins do find a mate that they take a shine to they carry out an intimate dance – stretching their necks from side to side in what appears to be an elaborate embrace. Occasionally, two males will engage in this mating dance, but the pair usually separate when one finds a female partner.

Prof Dobson’s team, which also includes researchers from the Centre for Functional and Evolutionary Ecology in Montpellier, France, has found that the penguins' bright yellow ear patches play an important role in attraction.

The researchers measured the size and colour intensity of these ear patches to find out how they affect penguin attractiveness. They also used black hair dye to artificially reduce the size of the ear patches.

Males with artificially-reduced ear patches seemed to have less success finding a female. Females also appeared to choose males with larger ear patches, and the researchers think that larger ear patches might convey a male's ability to defend his chick and his territory in the crowded colony.

The scientists hope to unpick the evolutionary mystery of how these birds select a suitable partner who will co-operate in the care of their egg and chick. They also hope to find out more about the penguins' natural behavior to see how they are being affected by environmental change.

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Macaroni Penguin (Eudyptes chrysolophus): correctly listed as Vulnerable?

2011-09-07T20:00:00.000-07:00

September 5, 2011 by Joe Taylor

BirdLife species factsheet for Macaroni Penguin
Macaroni Penguin Eudyptes chrysolophus breeds in at least 216 colonies at 50 sites in the higher latitudes of the southern hemisphere (Woehler 1993, Woehler and Croxall 1999). The total population is estimated by BirdLife to be c.9 million pairs, although it is argued that this is likely to be an underestimate because of potential underestimates in the South Georgia Island region (USFWS 2008). The species is listed as Vulnerable under criteria A2b,c; A3b,c; A4b,c, on the basis that the global population appears to have declined rapidly, by 30-49% over the preceding three generations, estimated to be c.34 years, and it is projected to decline by 30-49% over the next three generations. As noted in the assessment, however, the current classification is heavily reliant on the extrapolation of small-scale data, thus large-scale surveys are needed to confirm this categorisation.

The current trend estimate is based on recorded local declines. Populations on South Georgia and Bouvet Islands probably increased substantially in the 1960s and 1970s, but have subsequently decreased. Study populations on South Georgia declined by 65% from 1986 to 1998 (J. P. Croxall unpublished data), and the overall South Georgia population probably halved between c.1978 and 1998 (Trathan et al. 1998). Study populations on Marion Island decreased by 50% between 1979 and 1998. In contrast, populations on Kerguelen increased by c.1% per year between 1962 and 1985, and subsequent data from 1998 indicated that the colonies were stable or increasing (H. Weimerskirch per T. Micol in litt. 1999). Populations in South America may be stable, but data are scant.

The validity of the current assessment for this species has been brought into question by a review by the US Fish and Wildlife Services (USFWS 2008). Criticism was levelled at the use of trends at small study colonies to estimate the overall trend for the Prince Edward Islands. Likewise, the conclusion that overall numbers on South Georgia declined by 50% in the last two decades of the 20th century was criticised because it has not been empirically verified in the literature. Although the species is thought to have undergone a recent decline on Bouvet Island, there are apparently no current estimates for the population there. Significant recorded declines in colonies on Marion Island have also been questioned due to changes in survey methodology, and an overall decline of 18% in the island’s estimated total population between 1994-1995 and 2002-2003 is not considered significant by the USFWS (2008) in the context of small fluctuations in the three subsequent three breeding seasons. It has also been asserted that the decline noted on Prince Edward Island between 1976-1977 and 2001-2002, in which the estimated population fell from c.17,000 pairs to c.9,000 pairs (Crawford et al. 2003) was overestimated, and that the overall decline on Marion and Prince Edward Islands combined (c.3.4% of the species’s global population) was 32% between 1979 and 2003 (USFWS 2008).

These criticisms, combined with suggestions that some populations are stable or increasing, or have unknown trends, suggest that the overall estimated rate of decline should be reduced for this species. Comments on the current listing and further information on the species are requested.

References:

Crawford, R. J. M., Cooper, J., Dyer, B. M., Greyling, M., Klages, N. T. W., Ryan, P. G., Petersen, S., Underhill, L. G., Upfold, L., Wilkinson, W., de Villiers, M., du Plessis, S., du Toit, M., Leshoro, T. M. et al. (2003) Populations of surface nesting seabirds at Marion Island, 1994/95-2002/03. Afr. J. Mar. Sci. 25: 427-440.
Trathan, P. N., Croxall, J. P., Murphy, E. J. and Everson, I. (1998) Use of at-sea distribution data to derive potential foraging ranges of macaroni penguins during the breeding season. Mar. Ecol. Prog. Ser. 169: 263-275.
USFWS (2008) Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition To List Four Penguin Species as Threatened or Endangered Under the Endangered Species Act and Proposed Rule To List the Southern Rockhopper Penguin in the Campbell Plateau Portion of Its Range. Federal Register, Vol. 73: No. 244.
Woehler, E. J. (1993) The distribution and abundance of Antarctic and Subantarctic penguins. Cambridge, U.K.: Scientific Commission on Antarctic Research.
Woehler, E. J. and Croxall, J. P. (1999) The status and trends of Antarctic and subantarctic seabirds. Mar. Ornithol. 25: 43-66.

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ANTARCTICA: Long dives for Emperors

2011-09-05T19:59:00.000-07:00

04 September 2011
Issue: 187

Emperor penguins fishing at sea and at an experimental dive hole often spend minimal times on the surface even after dives that last far beyond their measured 5.6 minute aerobic dive limit.

Researchers from the US Scripps Institution of Oceanography and the International Coastal Research Center, Atmosphere and Ocean Research Institute at the University of Tokyo went to the Antarctic and attached accelerometer-based data loggers to Emperor penguins diving in the two different situations to evaluate the capacity of the birds to perform such dives without any apparent prolonged recovery periods.

In a report of the study published in the Journal of Experimental Biology, the researchers say the penguins regularly remain submerged for up to 12 minutes by carefully managing their oxygen reserves.

Lead researcher Paul Ponganis from the Scripps Institution says penguins diving from isolated ice holes fuel the dive aerobically for the first 5.6 minutes and supplement the remainder of the dive with anaerobic metabolism.

But when the researchers compared the aerobic dive limit for ice hole diving penguins with estimates of the aerobic dive limit for freely foraging animals, it appeared the free-ranging birds were able to sustain the aerobic portion of a dive for up to eight minutes. From the data loggers, they could see a surge every time the animal strokes with its wings and they could then count the number of peaks per dive to get the stroke rate pattern.

"We expected that stroke rate would be lower in dives at sea and because of that there would be less muscle work and less oxygen consumption and that would explain how these birds dive as long and as frequently as they do," Ponganis says. But the freely diving birds were stroking faster and were not extending their aerobic dive limit by beating their wings more slowly to conserve oxygen.

When the researchers compared the length of time spent by birds at the surface recovering from dives, the free divers spent no more time at the surface than the ice-hole divers.

Assuming the penguins did not exhale while submerged, they found the penguins carried more air as they extended their dives down to 300 metres, apparently anticipating how deep they would dive and adjusted the amount of air they carried down accordingly.

Yet penguins that dived 400 to 500 metres appeared to be carrying less air than the birds that only dived to 300 metres, leading Ponganis to conclude that they probably exhaled prior to the final segment of the dive.

On one occasion, the researchers recorded a dive where an emperor penguin remained submerged for a record-breaking 27.6 minutes although after it emerged from the water, the bird lay on the ice for six minutes before it stood, took another 20 minutes before it started walking and then waited a further eight hours before going back into the water.

Ponganis says the penguin was exhausted and believes the dive was extended when the pack ice shifted above the penguin's head, blocking its escape route. That it survived is a measure of the bird's remarkable capacity to conserve oxygen under water.

source

Enormous bird lived alongside dinosaurs

2011-08-10T07:46:00.000-07:00

Ostrich-like creature could have stood close to 10 feet tall, researchers say

John Conway

Two possible body shapes for the gigantic Samrukia nessovi, with a human and 'normal-sized' Mesozoic bird for scale.

By Jennifer Viegas

8/9/2011

An enormous prehistoric bird, which might have resembled a very big ostrich, lived alongside dinosaurs around 83 million years ago, according to new research.

The bird, called Samrukia nessovi after the mythical Kazakh Phoenix, lived in what is now Kazakhstan. It is described in the latest Royal Society Biology Letters.

The discovery confirms "that big birds were living alongside Cretaceous non-avian dinosaurs," lead author Darren Naish said. "In fact, these big birds fit into the idea that the Cretaceous wasn't 'a non-avian dinosaurs-only theme park.' Sure, non-avian dinosaurs were important and big in ecological terms, but there was at least some space for other land animals."

Naish is an honorary research associate in the School of Earth & Environmental Sciences at the University of Portsmouth. He and his team made the discovery after analyzing the fossil for Samrukia, which previously had been modified by someone to resemble an oviraptorosaur (a type of feathered dinosaur).

All that's left of this big bird is its toothless lower jaw. The structure and characteristics of the jaw are associated with birds and not non-avian dinosaurs, the researchers believe.

They conclude that the skull of the bird during its lifetime would have been about a foot long. If flightless, it could have stood close to 10 feet tall. If it flew, its wingspan is likely to have exceeded 13 feet.
The big bird is now the second known large avian from the dinosaur era. The first to be identified was Gargantuavis philoinos, which lived in southern France around 70 million years ago. It too may have been flightless and ostrich-like.

"So we can now be really confident that Mesozoic terrestrial birds weren't all thrush-sized or crow-sized animals," Naish said. "Giant size definitely evolved in these animals, and giant forms were living in at least two distinct regions. This fits into a larger, emerging picture: Mesozoic birds were ecologically diverse, with lots of overlap between them and modern groups."

During its day, Samrukia existed in an ecosystem that included armored dinosaurs, duckbilled dinosaurs, and tyrannosaurs — along with other predatory dinos. Smaller birds are also known from this site, called the Bostobynskaya Formation. Sharks, turtles and salamanders from the bird's time period have also been found in the region.

At present, the site is dry and hot. It's dominated by semi-desert or scrub. Back in the dinosaur era, it was more of a floodplain environment, with a flat plain crisscrossed by big, meandering rivers. Fossil wood suggests forests were nearby.

It remains unclear what the big bird hunted, but the researchers could not find any evidence for obvious specialization, such as dedication to plant consumption or aquatic prey. They therefore suspect it was a generalist, per many modern birds today.

The bird probably also spent a lot of time running or flying away from the numerous meat-eating dinosaurs from the area.

Such distinctions were obviously important to the animals at the time, but paleontologists now must tease apart birds from non-avian dinosaurs. In the case of this latest discovery, a fossil attributed to a dinosaur was determined to be a bird. Recently, however, the supposed "world's oldest known bird," Archaeopteryx, was found to be a non-avian dinosaur. Naish and his team agree with that assessment.

Lawrence Witmer, a professor of anatomy and paleontology at Ohio University, told Discovery News, "We scientists use the cumbersome and seemingly pedantic 'non-avian dinosaurs' (term), but back about 150 million years ago, all these groups were extremely similar. They all kind of looked like feathered dino-birds."
As Naish points out, though, the new findings about Samrukia demonstrate that modern birds "weren't as distinct from extinct groups of Mesozoic birds as people used to think."

Admiring today's birds therefore provides a hint about what avian diversity looked like millions of years ago, when non-avian dinosaurs were still alive and may have been feasting on these early birds.

Source

"Oldest Bird" knocked off its perch

2011-07-29T10:44:00.000-07:00

Xing Lida and Liu Yi

An artist's conception shows how the birdlike dinosaur known as Xiaotingia zhengi might have looked.

By Alan Boyle

The newfound fossil of a 155 million-year-old feathered dinosaur has led scientists to claim that Archaeopteryx, the species long held forth as the "oldest bird," is no bird at all.
Chinese researchers made the claim in Thursday's issue of the journal Nature, and an outside expert says the study "is likely to rock the paleontological community for years to come." Ohio University paleontologist Lawrence Witmer noted that the latest research, focusing on a fossil species dubbed Xiaotingia zhengi, comes 150 years after the discovery of Archaeopteryx, which marked a milestone in the study of the origin of birds.

"It's fitting that 150 years later, Archaeopteryx is right back at center stage," Witmer told me.
Xiaotingia was found by a collector in China's Liaoning Province, a hotbed for feathered-dino fossils, and sold to the Shandong Tianyu Museum of Nature. Paleontologists led by Xing Xu of the Chinese Academy of Sciences analyzed the fossil's skeletal measurements in detail and fed them into a computer database with measurements from 89 fossilized dinosaur and bird species, including Archaeopteryx.
Without Xiaotingia, the computer analysis put Archaeopteryx on the evolutionary line leading to modern-day birds. But when Xiaotingia was included, Archaeopteryx was placed in a group of birdlike dinosaurs known as deinonychosaurs. The differences had to do with details such as the shape of the wishbone and the skull's snout.

Archaeopteryx was about the size of a modern-day crow, and Xiaotingia was as big as a chicken.

Xu et al., Nature

The fossil skeleton of Xiaotingia zhengi is splayed out in rock.

"If you just looked at Xiaotingia, you'd say, 'Oh, boy, another little feathered dinosaur from China,'" Thomas Holtz, a paleontologist at the University of Maryland at College Park who reviewed the study for Nature, told me. "In and of itself, it is not a particularly unusual animal. But the combination of traits, at least in their analysis, pulls Archaeopteryx over to the deinonychosaur side of things."
The researchers acknowledged that their reclassification was "only weakly supported by the available data," but they said this kind of fuzziness was to be expected when the fossils being analyzed are close to the common ancestor of now-extinct dinosaurs and modern birds. "This phenomenon is also seen in some other major transitions, including the origins of major mammalian groups," they wrote.

Witmer agreed: "We're looking at an origin, and consequently it's going to be messy."
The 150 million-year-old Archaeopteryx fossil, which was discovered in southern Germany in 1861, was long seen as the oldest evidence of a bird species because the rocky imprint bore traces of feathers. But over the past decade or two, many dinosaur fossils have been found with evidence of feathers — to the extent that some scientists have been able to figure out how the feathers were colored. As a result, some researchers have argued for years that Archaeopteryx should be reclassified.

In the past, creationists have used Archaeopteryx in their arguments against evolutionary theory, contending that birds always existed in their feathered form and did not evolve from dinosaurs. Evolution's critics may try to spin these latest findings to their advantage as well, Witmer said.
"It may well be they're going to suggest that we evolutionists don't know what we're doing," he told me. "In reality, it's just the opposite. It just shows what evolution is all about. A prediction of evolutionary theory is that it should be really hard for us to figure out what's going on in an origin."

Archaeopteryx's dethronement means the title of "oldest bird" could fall to other ancient species, such as Epidexipteryx hui, Jeholornis and Sapeornis, Witmer said. "They're not exactly household names," he noted. "These new characters have been known only for 10 years or less." Archaeopteryx, meanwhile, would be lumped in with Xiaotingia as well as another feathered-dino species called Anchiornis huxleyi.

G. Mayr / Senckenberg

An Archaeopteryx specimen highlights wing and tail feather impressions.

The renewed debate over Archaeopteryx's classification is far from finished. Holtze said he knew some researchers who were inclined to go with a completely different classification scheme, which would put the deinonychosaurs along with Archaeopteryx on the evolutionary line leading to modern-day birds.
The debate could also require a rethinking of how birds arose, and how features such as feathers and flight developed. Holtz said some paleontologists have suggested that Archaeopteryx was not a particularly good flier, and putting it in the deinonychosaur category would make more sense on that score. It may turn out that deinonychosaurs gradually evolved from so-so fliers into feathered but flightless animals. "They would have been nasty predatory analogs to ostriches," Holtz said.

Holtz acknowledged that Archaeopteryx "has been our image of what early birds are like, for the historical reason that it's been known for 150 years as having all these feathers." The fact that the fossil was found just two years after Charles Darwin published "On the Origin of Species" added to its image as an evolutionary icon. A dramatic change in that image might come as another scientific shock to folks who are already being told that there's no such thing as a brontosaur, and that Pluto no longer ranks among the solar system's major planets.

"To which I say, 'Get over it!'" Holtz said. "Science is about changing ideas based on evidence, not about ignoring evidence to conform to our comfortable ideas."

Source

Drag Reduction by Air Release Promotes Fast Ascent in Jumping Emperor Penguins paper download link

2011-07-14T03:44:00.000-07:00

Drag reduction by air release promotes fast ascent in jumping emperor penguins—a novel hypothesis

John Davenport^1,*, Roger N. Hughes², Marc Shorten¹, Poul S. Larsen³

¹Department of Zoology, Ecology and Plant Science, University College Cork, Distillery Fields, North Mall, Cork, Ireland
²School of Biological Sciences, Bangor University, Deiniol Road, Bangor, Gwynedd LL57 2UW, UK
³Department of Mechanical Engineering, Fluid Mechanics Section, Technical University of Denmark, Building 403,
2800 Kgs. Lyngby, Denmark

*Email: j.davenport@ucc.ie

ABSTRACT: To jump out of water onto sea ice, emperor penguins must achieve sufficient underwater speed to overcome the influence of gravity when they leave the water. The relevant combination of density and kinematic viscosity of air is much lower than for water. Injection of air into boundary layers (‘air lubrication’) has been used by engineers to speed movement of vehicles (ships, torpedoes) through sea water. Analysis of published and unpublished underwater film leads us to present a hypothesis that free-ranging emperor penguins employ air lubrication in achieving high, probably maximal, underwater speeds (mean ± SD: 5.3 ± 1.01 m s^–1), prior to jumps. Here we show evidence that penguins dive to 15 to 20 m with air in their plumage and that this compressed air is released as the birds subsequently ascend whilst maintaining depressed feathers. Fine bubbles emerge continuously from the entire plumage, forming a smooth layer over the body and generating bubbly wakes behind the penguins. In several hours of film of hundreds of penguins, none were seen to swim rapidly upwards without bubbly wakes. Penguins descend and swim horizontally at about 2 m s^–1; from simple physical models and calculations presented, we hypothesize that a significant proportion of the enhanced ascent speed is due to air lubrication reducing frictional and form drag, that buoyancy forces alone cannot explain the observed speeds, and that cavitation plays no part in bubble formation.

Download this paper HERE

Penguins Take to the Air!

2011-07-14T03:40:00.000-07:00

Matt Walker | Wednesday, 13 July 2011

An Emperor penguin leaps from the water (Image: Blue Planet, BBC)

Penguins can’t fly. But they can get airborne.
In fact, taking to the air, for even a brief instant, is actually a vital strategy penguins employ to avoid being eating by predators such as leopard seals or orcas.
Now scientists have worked out the secret technique that penguins use to get airborne. It involves wrapping their bodies in a cloak of air bubbles – and it turns out to be the same technique that engineers use to speed the movement of ships and torpedoes through water.
Another interesting aspect of the discovery is that it was made by scientists examining in minute detail footage shot for the programme Blue Planet, a landmark natural history series filmed by the BBC’s own Natural History Unit.

It sounds implausible that penguins might get airborne. These short, squat birds, which tend to live in the colder parts of the southern hemisphere, are renowned for their waddling walks and flapping flippers – which are famously great for swimming, but useless for flying.
But many species of penguin do take to the air.
Due to their body shape, and poor climbing ability, it is difficult for penguins to haul themselves ashore, especially onto rocky shorelines. And it can be almost impossible for a penguin to haul itself out from the ocean onto sea ice.

Emperor penguins create bubble trails (image: Blue Planet, BBC)

So penguins leap ashore: they swim at speed to the surface, burst through and briefly get airborne to clear the rocks or ice shelf, and land on their breast.
Smaller species, such as Adelie penguins, can leap 2-3 metres out of the water, landing unscathed onto broken rock. Bigger species, such as Emperor penguins (the largest of all), reach heights of 20 – 45 cm, but that is enough for them to leap out of holes in the ice and clear the ice’s edge.
But one aspect of this leaping behaviour has long puzzled biologists. As the birds swim toward the surface, they trail a wake of bubbles behind them. No one knew where these bubbles come from, or why there are there.
Five years ago, that began to change when a group of biologists met in a pub in Cork, the Irish Republic, before the start of a scientific symposium.

Professor Roger Hughes from Bangor University in Gwynedd recalled how he’d seen a wildlife film in which penguins trailed bubbles in this way and asked his colleague Professor John Davenport, of University College Cork, if he knew why they did so.

Adelie penguins leap high (image: photolibrary.com)

Professor Davenport did not, but set off to find out with his PhD student Marc Shorten.
Together they obtained footage from the BBC of its Blue Planet series, which filmed breaching penguins for its Frozen Seas episode.

(Watch below how Emperor penguins first evade a leopard seal, then when the coast is clear, they trail a wake of bubbles before leaping from the water)
The scientists slowed down this footage, analysing the speeds and angles of emperor penguins exiting the water, developing a basic biomechanical model of what was going on.
During this analysis, the researchers made some interesting discoveries. The bubbles of air being trailed by the penguins weren’t coming out of the birds’ lungs via the beak.
Instead, they were coming from the birds’ feathers.

“We were amazed to find that,” Professor Davenport tells me.
The researchers also realised that these air bubbles form a “coat” around the birds’ bodies as they rocket toward the surface at speeds of 19km an hour.
To investigate further, the three scientists teamed up with Professor Poul Larsen from the Danish Technical University in Lyngby, who brought his expertise in mathematics and fluid mechanics to the research.
The four scientists have now just published the results of their study.

The “coat of air bubbles” first noticed on the Blue Planet footage is indeed what enables the penguins to get air as they leap onto land.
Penguins have great control over their plumage, Professor Davenport tells me.
They raise their feathers to fill their plumage with air, then dive underwater. As the birds descend, the water pressure increases, decreasing the volume of the trapped air. At a depth of 15-20 metres, for example, the air volume has shrunk by up to 75%.

The birds now depress their feathers, locking them around the new, reduced air volume.
The penguin then swims vertically up as fast as it can, and the air in the plumage expands and pours through the feathers.
“Because the feathers are very complex, the pores through which the air emerges are very small so the bubbles are initially tiny. They coat the outer feather surface.”
Crucially, this coat of small air bubbles acts as a lubricant, drastically reducing drag, enabling the penguins to reach lift-off speeds.

This air insulation effect is known to boat architects and engineers. By placing a layer of air around a ship’s hull, or torpedo, for example, designers can dramatically reduce drag, and speed up the boat or weapon’s passage through the water as a result.
But “this process has never been thought of before as having a biological role,” says Professor Davenport.
The penguins also appear to have overcome one other issue that blights naval architects trying to exploit “air lubrication” underwater.

The moment before lift off (image: Blue Planet, BBC)

Although a coat of tiny bubbles dramatically reduces drag, it can also have a major slowing effect if the bubbles reach a ship or torpedo’s propeller. That’s because the propeller starts pushing against air not water.
However, a penguin’s flippers, its means of propulsion equivalent to the propeller, are held outside of the bubble clouds, so they are not affected.

This wonderful insight into how penguins leap out of the water has just been published in the Marine Ecology Progress Series journal.

It brings a whole new meaning to the expression “getting air”.

Source

A New Book on My "Must Read" List--Pioneers in Penguin Science

2011-07-11T12:18:00.000-07:00

'Empire of Ice': The scientific quests of the Antarctic explorers

In "Empire of Ice," Pulitzer Prize-winning author and historian Edward J. Larson looks at how dedication to science powered many of the Antarctic's most daring expeditions.

By David B. Williams

Special to The Seattle Times

'An Empire of Ice: Scott, Shackleton, and the Heroic Age of Antarctic Science'
by Edward J. Larson
Yale University Press, 326 pp., $28

Leaving in the pitch black of the Antarctic winter of 1911, Edward Wilson, Apsley Cherry-Garrard and Birdie Bowers set out to find penguins. They were part of Robert Falcon Scott's second Antarctic expedition. To reach the birds, they man-hauled two sledges carrying 750 pounds, which often led to them having to relay the overweight sledges, so that for each mile advanced, they walked three. Moonlight provided a little light, but still they dropped into unseen crevasses and bumped into ice hummocks. And it was rather chilly, with temperatures dropping to minus-75.8 degrees F.

When they arrived at the penguin colony, the men built a stone hut, covered by a canvas tent. They were able to collect a few birds and eggs before a blizzard hit. Trapped for days, Cherry-Garrard wrote that the wind "sounded like the rush of an express train through a tunnel." Everything was frozen, and when the wind took the tent, the men had to cower in their exposed bags.

Their return trip to their base was even worse. Having had little success at the penguin colony, they had to man-haul 16 hours a day in mostly darkness, and Cherry-Garrard's jaw chattered so violently he shattered all of his teeth.

This "worst journey in the world," as it came to be called, was not the only time Wilson had risked his life to observe Antarctic penguins. He had studied the birds on Scott's previous expedition. But all of the hardships were worth it because "they did it for science," writes Edward J. Larson, in his new book, "An Empire of Ice: Scott, Shackleton, and the Heroic Age of Antarctic Science."

Writing about Scott's and Ernest Shackleton's Antarctic expeditions is a cottage industry. New books analyzing everything from the men's leadership abilities to how and why their reputations have changed appear regularly.
To his credit, Pulitzer Prize-winner Larson offers a new take by looking at how science drove many of the expeditions. As he did in previous books such as "Summer for the Gods" and "Evolution's Workshop," Larson combines careful reading of the primary documents, a thorough knowledge of the players, and first-rate writing to produce a compelling book. That having been said, this book's main appeal will be to those already familiar with the expeditions and those interested in the history of science.

My only complaint is the maps. I appreciate that Larson used historic maps from the expeditions, but they are very hard to read and often filled with too much surplus data. The photographs, however, are a nice addition.
The men took their research seriously, often making incredible sacrifices in the name of science, whether it be meteorology, biology or geology. They did so in part because they were British and felt that as citizens of the leading nation of the world, it was their responsibility to be the first to penetrate the unknown realms, to study them, and to write lengthy descriptions of what had been found.

Larson effectively argues that although some may look derisively back at Scott and Shackleton as relics of the Edwardian age, their scientific work should be considered as "modern and forward-looking enterprises." After all, Antarctica has become "fundamentally a place of science," and these expeditions led the way.

Source

Pterosaurs Not Driven Into Extinction by Birds, Study Reveals

2011-07-08T04:32:00.000-07:00

New research finds that pterosaurs, flying reptiles from the time of the dinosaurs, were not driven to extinction by the birds, but in fact they continued to diversify and innovate for millions of years afterward. (Credit: iStockphoto/Linda Bucklin)

The Rise and Rise of the Flying Reptiles: Pterosaurs Not Driven Into Extinction by Birds, Study Reveals

ScienceDaily (July 7, 2011) — Pterosaurs, flying reptiles from the time of the dinosaurs, were not driven to extinction by the birds, but in fact they continued to diversify and innovate for millions of years afterwards.

A new study by Katy Prentice, done as part of her undergraduate degree (MSci in Palaeontology and Evolution) at the University of Bristol, shows that the pterosaurs evolved in a most unusual way, becoming more and more specialised through their 160 million years on Earth. The work is published in the Journal of Systematic Palaeontology.

"Usually, when a new group of animals or plants evolves, they quickly try out all the options. When we did this study, we thought pterosaurs would be the same," said Katy. "Pterosaurs were the first flying animals -- they appeared on Earth 50 million years before Archaeopteryx, the first bird -- and they were good at what they did. But the amazing thing is that they didn't really begin to evolve until after the birds had appeared."
Katy's study was done in conjunction with her supervisors, Dr Marcello Ruta and Professor Michael Benton. They looked at 50 different pterosaurs that ranged in size from a blackbird to the largest of all, Quetzalcoatlus, with a wingspan of 12 metres, four times the size of the largest flying bird today, the albatross. They tracked how all the pterosaur groups came and went through their history and recorded in detail their body shapes and adaptations.

The new work shows that pterosaurs remained conservative for 70 million years, and then started to experiment with all kinds of new modes of life. After birds emerged and became successful, the pterosaurs were not pushed to extinction, as had been suggested. It seems they responded to the new flyers by becoming larger and trying out new lifestyles. Many of the new lifestyle adaptations were seen in the pterosaurs skulls, as they adapted to feed on different food sources; some were seed-eaters, many ate fish, and later ones even lost their teeth. The rest of the body also showed a surprising amount of variation between different groups, when considering that the body forms have to retain many features to allow flight.

"Pterosaurs were at the height of their success about 125 million years ago, just as the birds became really diverse too," said Dr Marcello Ruta. "Our new numerical studies of all their physical features show they became three times as diverse in adaptations in the Early Cretaceous than they had been in the Jurassic, before Archaeopteryx and the birds appeared."

Pterosaurs dwindled and disappeared 65 million years during the mass extinction that killed the dinosaurs. In their day they had been a fair match for the birds, and the two groups divided up aerial ecospace between them, so avoiding conflict.

"We're delighted to see a student mastering some tough mathematical techniques, and coming up with such a clear-cut result," said Professor Michael Benton. "Palaeontologists have often speculated about the coming and going of different groups of animals through time, but the new study provides a set of objective measurements of the relative success and breadth of adaptation of pterosaurs through their long time on the Earth."
Further information can be found on the Palaeobiology and Biodiversity Research Group's website: The rise and rise of the flying reptiles (http://palaeo.gly.bris.ac.uk/macro/pterosaurs.html).

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of Bristol.

Journal Reference:

Katherine C. Prentice, Marcello Ruta, Michael J. Benton. Evolution of morphological disparity in pterosaurs. Journal of Systematic Palaeontology, 2011; DOI: 10.1080/14772019.2011.565081

University of Bristol (2011, July 7). The rise and rise of the flying reptiles: Pterosaurs not driven into extinction by birds, study reveals. ScienceDaily. Retrieved July 8, 2011, from http://www.sciencedaily.com /releases/2011/07/110706101608.htm

New Theory On Origin of Birds: Enlarged Skeletal Muscles

2011-07-03T10:55:00.000-07:00

Ostriches in South Africa's Kruger National Park. A developmental biologist is proposing a new theory of the origin of birds, which traditionally has been thought to be driven by the evolution of flight. The new theory credits the emergence of enlarged skeletal muscles as the basis for their upright two-leggedness, which led to the opportunity for other adaptive changes like flying or swimming. (Credit: © David Garry / Fotolia)

ScienceDaily (July 2, 2011) — A developmental biologist at New York Medical College is proposing a new theory of the origin of birds, which traditionally has been thought to be driven by the evolution of flight. Instead, Stuart A. Newman, Ph.D., credits the emergence of enlarged skeletal muscles as the basis for their upright two-leggedness, which led to the opportunity for other adaptive changes like flying or swimming. And it is all based on the loss of a gene that is critical to the ability of other warm-blooded animals to generate heat for survival.

Dr. Newman, a professor of cell biology and anatomy, studies the diversity of life and how it got that way. His research has always centered on bird development, though this current study, "Thermogenesis, muscle hyperplasia, and the origin of birds," also draws from paleontology, genetics, and the physiology of fat.
Dr. Newman draws on earlier work from his laboratory that provided evidence for the loss, in the common dinosaur ancestors of birds and lizards, of the gene for uncoupling protein-1 (UCP1). The product of this gene is essential for the ability of "brown fat," tissue that protects newborns of mammals from hypothermia, to generate heat. In birds, heat generation is mainly a function of skeletal muscles.

"Unlike the scenario in which the evolution of flight is the driving force for the origin of birds, the muscle expansion theory does not require functionally operative intermediates in the transition to flight, swimming, or winglessness, nor does it require that all modern flightless birds, such as ostriches and penguins, had flying ancestors. It does suggest that the extinction of non-avian dinosaurs may have been related to a failure to evolve compensatory heat-generating mechanisms in face of the loss of UCP1," says the scientist

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by New York Medical College, via EurekAlert!, a service of AAAS.

Journal References:

Stuart A. Newman. Thermogenesis, muscle hyperplasia, and the origin of birds. BioEssays, 2011; DOI: 10.1002/bies.201100061
Nadejda V Mezentseva, Jaliya S Kumaratilake, Stuart A Newman. The brown adipocyte differentiation pathway in birds: An evolutionary road not taken. BMC Biology, 2008; 6 (1): 17 DOI: 10.1186/1741-7007-6-17

New York Medical College (2011, July 2). New theory on origin of birds: Enlarged skeletal muscles. ScienceDaily. Retrieved July 3, 2011, from http://www.sciencedaily.com /releases/2011/06/110622115317.htm

Latest Research on the History of Antarctica

2011-06-28T16:14:00.000-07:00

Researchers ascertained the exact species of plants that existed on the Antarctic Peninsula over the past 36 million years during a three-year examination of thousands of grains of fossilized pollen, including this grain from the tree Nothofagus fusca. (Credit: S. Warny/LSU)

Fossilized Pollen Reveals Climate History of Northern Antarctica: Tundra Persisted Until 12 Million Years Ago

ScienceDaily (June 27, 2011) — A painstaking examination of the first direct and detailed climate record from the continental shelves surrounding Antarctica reveals that the last remnant of Antarctic vegetation existed in a tundra landscape on the continent's northern peninsula about 12 million years ago.

The research, which was led by researchers at Rice University and Louisiana State University, appears online this week and will be featured on the cover of the July 12 issue of the Proceedings of the National Academy of Sciences.

The new study contains the most detailed reconstruction to date of the climatic history of the Antarctic Peninsula, which has warmed significantly in recent decades. The rapid decline of glaciers along the peninsula has led to widespread speculation about how the rest of the continent's ice sheets will react to rising global temperatures.

"The best way to predict future changes in the behavior of Antarctic ice sheets and their influence on climate is to understand their past," said Rice University marine geologist John Anderson, the study's lead author. The study paints the most detailed picture to date of how the Antarctic Peninsula first succumbed to ice during a prolonged period of global cooling.

In the warmest period in Earth's past 55 million years, Antarctica was ice-free and forested. The continent's vast ice sheets, which today contain more than two-thirds of Earth's freshwater, began forming about 38 million years ago. The Antarctic Peninsula, which juts farther north than the rest of the continent, was the last part of Antarctica to succumb to ice. It's also the part that has experienced the most dramatic warming in recent decades; its mean annual temperatures rose as much as six times faster than mean annual temperatures worldwide.

"There's a longstanding debate about how rapidly glaciation progressed in Antarctica," said Sophie Warny, a Louisiana State University geologist who specializes in palynology (the study of fossilized pollen and spores) and led the palynological reconstruction. "We found that the fossil record was unambiguous; glacial expansion in the Antarctic Peninsula was a long, gradual process that was influenced by atmospheric, tectonic and oceanographic changes."

Warny, her students and colleague Rosemary Askin were able to ascertain the exact species of plants that existed on the peninsula over the past 36 million years after a painstaking, three-year examination of thousands of individual grains of pollen that were preserved in muddy sediments beneath the sea floor just off the coast.
"The pollen record in the sedimentary layers was beautiful, both in its richness and depth," Warny said. "It allowed us to construct a detailed picture of the rapid decline of the forests during the late Eocene -- about 35 million years ago -- and the widespread glaciation that took place in the middle Miocene -- about 13 million years ago."

Obtaining the sedimentary samples wasn't easy. The muddy treasure trove was locked away beneath almost 100 feet of dense sedimentary rock. It was also off the coast of the peninsula in shallow waters that are covered by ice most of the year and beset by icebergs the rest. Anderson, a veteran of more than 25 research expeditions to Antarctica, and colleagues spent more than a decade building a case for the funding to outfit an icebreaker with the right kind of drilling equipment to bore through the rock.

In 2002, the National Science Foundation (NSF) funded the project, which was dubbed SHALDRIL. Three years later, the NSF research vessel Nathaniel B. Palmer left on the first of two drilling cruises.

"It was the worst ice year that any of us could remember," Anderson said. "We'd spend most of a day lowering drill string to the ocean floor only to pull it back up to get out of the way of approaching icebergs."
The next year was little better, but the SHALDRIL team managed to obtain enough core samples to cover the past 36 million years, thanks to the logistical planning of marine geologist Julia Wellner and to the skill of the drilling crew. By end of the second season, Anderson said, the crew could drill as much as a meter every five minutes.

Reconstructing a detailed climate record from the sample was another Herculean task. In addition to the three-year palynological analysis at LSU, University of Southampton palaeoceanographer Steven Bohaty led an effort to nail down the precise age of the various sediments in each core sample. Wellner, now at the University of Houston, examined the characteristics of the sediments to determine whether they formed below an ice sheet, in open marine conditions or in a combined glacial-marine setting. Other members of the team had to count, categorize and even examine the surface texture of thousands of sand grains that were preserved in the sediments. Gradually, the team was able to piece together a history of how much of the peninsula was covered by glaciers throughout the past 36 million years.

"SHALDRIL gave us the first reliable age constraints on the timing of ice sheet advance across the northern peninsula," Anderson said. "The rich mosaic of organic and geologic material that we found in the sedimentary record has given us a much clearer picture of the climatic history of the Antarctic Peninsula. This type of record is invaluable as we struggle to place in context the rapid changes that we see taking place in the peninsula today."

The study was funded by grants from the NSF's Office of Polar Programs to Anderson and Warny. Study co-authors include Wellner; Askin; Bohaty; Alexandra Kirshner, Tyler Smith and Fred Weaver, all of Rice; Alexander Simms and Daniel Livsey, both of the University of California, Santa Barbara; Werner Ehrmann of the University of Leipzig; Lawrence Lawver of the University of Texas at Austin; David Barbeau of the University of South Carolina; Sherwood Wise and Denise Kulhenek, both of Florida State University; and Wojciech Majewski of the Polish Academy of Sciences.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Rice University.

Journal Reference:

John B. Anderson, Sophie Warny, Rosemary A. Askin, Julia S. Wellner, Steven M. Bohaty, Alexandra E. Kirshner, Daniel N. Livsey, Alexander R. Simms, Tyler R. Smith, Werner Ehrmann, Lawrence A. Lawver, David Barbeau, Sherwood W. Wise, Denise K. Kulhenek, Fred M. Weaver, Wojciech Majewski. Progressive Cenozoic cooling and the demise of Antarctica’s last refugium. Proceedings of the National Academy of Sciences, 2011; DOI: 10.1073/pnas.1014885108

Rice University (2011, June 27). Fossilized pollen reveals climate history of northern Antarctica: Tundra persisted until 12 million years ago. ScienceDaily. Retrieved June 28, 2011, from http://www.sciencedaily.com /releases/2011/06/110627163508.htm

Body Temperatures of Dinosaurs Measured for First Time: Some Dinosaurs Were as Warm as Most Modern Mammals

2011-06-27T11:33:00.000-07:00

Caltech geochemists Rob Eagle (left) and John Eiler adjust equipment used to analyze the isotopic concentrations in dinosaur teeth and reveal the body temperature of the extinct creatures. (Credit: Caltech / Lance Hayashida)

ScienceDaily (June 23, 2011) — Were dinosaurs slow and lumbering, or quick and agile? It depends largely on whether they were cold or warm blooded. When dinosaurs were first discovered in the mid-19th century, paleontologists thought they were plodding beasts that had to rely on their environments to keep warm, like modern-day reptiles. But research during the last few decades suggests that they were faster creatures, nimble like the velociraptors or T. rex depicted in the movie Jurassic Park, requiring warmer, regulated body temperatures like in mammals.

Now, a team of researchers led by the California Institute of Technology (Caltech) has developed a new approach to take body temperatures of dinosaurs for the first time, providing new insights into whether dinosaurs were cold or warm blooded. By analyzing isotopic concentrations in teeth of sauropods, the long-tailed, long-necked dinosaurs that were the biggest land animals to have ever lived -- think Apatosaurus (also known as Brontosaurus) -- the team found that the dinosaurs were about as warm as most modern mammals.

"This is like being able to stick a thermometer in an animal that has been extinct for 150 million years," says Robert Eagle, a postdoctoral scholar at Caltech and lead author on the paper to be published online in the June 23 issue of Science Express.

"The consensus was that no one would ever measure dinosaur body temperatures, that it's impossible to do," says John Eiler, a coauthor and the Robert P. Sharp Professor of Geology and professor of geochemistry. And yet, using a technique pioneered in Eiler's lab, the team did just that.

The researchers analyzed 11 teeth, dug up in Tanzania, Wyoming, and Oklahoma, that belonged to Brachiosaurus brancai and Camarasaurus. They found that the Brachiosaurus had a temperature of about 38.2 degrees Celsius (100.8 degrees Fahrenheit) and the Camarasaurus had one of about 35.7 degrees Celsius (96.3 degrees Fahrenheit), warmer than modern and extinct crocodiles and alligators but cooler than birds. The measurements are accurate to within one or two degrees, Celsius.

"Nobody has used this approach to look at dinosaur body temperatures before, so our study provides a completely different angle on the longstanding debate about dinosaur physiology," Eagle says.

The fact that the temperatures were similar to those of most modern mammals might seem to imply that dinosaurs had a warm-blooded metabolism. But, the researchers say, the issue is more complex. Because large sauropod dinosaurs were so huge, they could retain their body heat much more efficiently than smaller mammals like humans. "If you're an animal that you can approximate as a sphere of meat the size of a room, you can't be cold unless you're dead," Eiler explains. So even if dinosaurs were "cold blooded" in the sense that they depended on their environments for heat, they would still have warm body temperatures.

"The body temperatures we've estimated now provide a key piece of data that any model of dinosaur physiology has to be able to explain," says Aradhna Tripati, a coauthor who's an assistant professor at UCLA and visiting researcher in geochemistry at Caltech. "As a result, the data can help scientists test physiological models to explain how these organisms lived."

The measured temperatures are lower than what's predicted by some models of body temperatures, suggesting there is something missing in scientists' understanding of dinosaur physiology. These models imply dinosaurs were so-called gigantotherms, that they maintained warm temperatures by their sheer size. To explain the lower temperatures, the researchers suggest that the dinosaurs could have had some physiological or behavioral adaptations that allowed them to avoid getting too hot. The dinosaurs could have had lower metabolic rates to reduce the amount of internal heat, particularly as large adults. They could also have had something like an air-sac system to dissipate heat. Alternatively, they could have dispelled heat through their long necks and tails.
Previously, researchers have only been able to use indirect ways to gauge dinosaur metabolism or body temperatures. For example, they infer dinosaur behavior and physiology by figuring out how fast they ran based on the spacing of dinosaur tracks, studying the ratio of predators to prey in the fossil record, or measuring the growth rates of bone. But these various lines of evidence were often in conflict. "For any position you take, you can easily find counterexamples," Eiler says. "How an organism budgets the energy supply that it gets from food and creates and stores the energy in its muscles -- there are no fossil remains for that," he says. "So you just sort of have to make your best guess based on indirect arguments."

But Eagle, Eiler, and their colleagues have developed a so-called clumped-isotope technique that shows that it is possible to take body temperatures of dinosaurs -- and there's no guessing involved. "We're getting at body temperature through a line of reasoning that I think is relatively bullet proof, provided you can find well-preserved samples," Eiler says. In this method, the researchers measure the concentrations of the rare isotopes carbon-13 and oxygen-18 in bioapatite, a mineral found in teeth and bone. How often these isotopes bond with each other -- or "clump" -- depends on temperature. The lower the temperature, the more carbon-13 and oxygen-18 tend to bond in bioapatite. So measuring the clumping of these isotopes is a direct way to determine the temperature of the environment in which the mineral formed -- in this case, inside the dinosaur.

"What we're doing is special in that it's thermodynamically based," Eiler explains. "Thermodynamics, like the laws of gravity, is independent of setting, time, and context." Because thermodynamics worked the same way 150 million years ago as it does today, measuring isotope clumping is a robust technique.

Identifying the most well-preserved samples of dinosaur teeth was one of the major challenges of the analysis, the researchers say, and they used several ways to find the best samples. For example, they compared the isotopic compositions of resistant parts of teeth -- the enamel -- with easily altered materials -- dentin and fossil bones of related animals. Well-preserved enamel would preserve both physiologically possible temperatures and be isotopically distinct from dentin and bone.

The next step is to take temperatures of more dinosaur samples and extend the study to other species of extinct vertebrates, the researchers say. In particular, taking the temperature of unusually small and young dinosaurs would help test whether dinosaurs were indeed gigantotherms. Knowing the body temperatures of more dinosaurs and other extinct animals would also allow scientists to learn more about how the physiology of modern mammals and birds evolved.

In addition to Eagle, Eiler, and Tripati, the other authors are Thomas Tütken from the University of Bonn, Germany; Caltech undergraduate Taylor Martin; Henry Fricke from Colorado College; Melissa Connely from the Tate Geological Museum in Casper, Wyoming; and Richard Cifelli from the University of Oklahoma. Eagle also has a research affiliation with UCLA.

This research was supported by the National Science Foundation and the German Research Foundation.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by California Institute of Technology. The original article was written by Marcus Woo.

Journal Reference:

Robert A. Eagle, Thomas Tütken, Taylor S. Martin, Aradhna K. Tripati, Henry C. Fricke, Melissa Connely, Richard L. Cifelli, John M. Eiler. Dinosaur Body Temperatures Determined from Isotopic (¹³C-¹⁸O) Ordering in Fossil Biominerals. Science, 2011; DOI: 10.1126/science.1206196

California Institute of Technology (2011, June 23). Body temperatures of dinosaurs measured for first time: Some dinosaurs were as warm as most modern mammals. ScienceDaily. Retrieved June 27, 2011, from http://www.sciencedaily.com /releases/2011/06/110623141312.htm

Why Penguins Are Afraid of the Dark

2011-06-24T10:45:00.000-07:00

byVirginia Morell on 23 June 2011

Like daily commuters, Adélie and emperor penguins are up at dawn, catching krill and fish in Antarctic waters, and back home to shore at dusk. Yet the food they prefer to dine on is easiest to catch after dark. Most researchers assumed that penguins had poor nighttime vision, which was why they stayed out of the water after dusk.

But in a new study, two marine ecologists argue that the penguins actually have no trouble seeing in the dark. Instead, they say, penguins head for shore at night because they cannot gauge the risk of being eaten by leopard seals or killer whales. Even their migration patterns, when they move from some of the Southern Ocean's most productive waters into those that are marginal, are likely shaped by the fear of predators. "They would rather be hungry" than dead, says the study's lead author, David Ainley, a marine ecologist at H. T. Harvey and Associates, an ecological consulting firm in Los Gatos, California.

To show that the penguins can see in the dark, Ainley and his colleague, Grant Ballard, a marine ecologist at PRBO Conservation Science, a conservation organization in Petaluma, California, outfitted 65 adult Adélie penguins with time-depth recorders. The devices, which register depth and light every second, were taped to the lower back, so that they caused the least amount of drag. Data collected on nearly 22,000 of the birds' foraging dives showed that most were hunting prey at 50 to 100 meters below the surface, where the water is quite dark—akin to early night. The birds also made a significant number of dives into deeper, darker waters, where they can forage successfully.

Although the two researchers did not collect similar data on emperor penguins, other scientists have shown that these birds dive even deeper, into waters more than 500 meters below the surface. "At that depth, it's absolutely black," Ainley says.

So why won't the penguins hunt at night? Ainley and Ballard note that leopard seals, which regularly kill both species of penguins, rest at midday, making it safer for penguins to hunt during this time. Even then, the penguins are cautious; they stay in the water only long enough to feed, and they're adept at remaining motionless when they're on thin ice and spot a leopard seal. At the Ross Island colony in Antarctica, Adélies that land at the far end of the island will even walk the 5 kilometers to reach their home rather than enter the water again and swim, which would get them back faster.

Killer whales may also be a problem. Although they have not been actually observed taking either Adélie or emperor penguins, cetacean researchers suspect that they do, because orcas have been seen killing and eating other penguin species in Antarctic and subantarctic waters. What's more, certain types of killer whales are prey specialists, feeding only on marine mammals and seabirds, and in the Antarctic these orcas are known to visit areas near emperor penguin colonies.

Fear of predators doesn't just affect the penguins' daily activities, however. It also influences the birds' migration patterns, Ainley and Ballard report this week in Polar Biology. Emperor penguin adults and chicks leave their colonies in the late Antarctic summer. But instead of heading to the closest and richest waters, they swim north to far less productive waters. During that journey, other researchers have noted, some 20% to 30% of juvenile emperors are killed.

"We don't have the evidence, but it is very likely killer whales are taking them," Ainley says. Similarly, the Adélie penguins migrate to northern areas in the Antarctic winter, presumably because they do not want to live in total darkness in the south. It's more difficult to spot predators during this period, Ainley says.
"They've provided a convincing argument for what look like very strange behaviors" on the part of the penguins, says Aaron Wirsing, a behavioral ecologist at the University of Washington, Seattle. "It's another good example of how widespread the ecology of fear is in nature," adds William Ripple, an ecologist at Oregon State University in Corvallis, who has studied the effects of fear on the elk population in Yellowstone National Park following the reintroduction of gray wolves. "Predators, and the fear they instill, are major shapers of ecosystems," he says.

Source

A Message from Dr. Dee Boersma

2011-06-04T12:46:00.000-07:00

Penguin_Update

Hi all-

I hope you'll take a quick look at the contents to our most recent issue of Conservation Magazine

. If you don't subscribe, try our free offer. I think it's a quality magazine that is well worth the read. We are small but in my view we should be big. We need more subscribers. Please tell your friends about us and help support getting quality science to a broad audience.

www.conservationmagazine.org

Dee

P. Dee Boersma Ph.D
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Dept of Biology
University of Washington
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Box 351800
Seattle WA 98195-1800 USA

Phone (206) 616-2185
FAX (206) 543-3041
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Coordinated Movements in a Penguin Huddle

2011-06-03T13:21:00.000-07:00

Coordinated movements in an emperor penguin huddle: (A) Observed field of view of the emperor penguin colony. The image shows several huddles and individual penguins. The density of penguins in huddles is approximately 21 animals per square meter. (B) The penguins' yellow and white face patch was used to track individual animals. (C) Typical trajectory of a penguin during huddle movements. Motionless periods are interrupted by intermittent small steps that lead over time to a reorganization of the entire huddle. (D) Positions of penguins tracked over 4 hours show a collective huddle movement as indicated by red arrows (movies available online). (E) Trajectories from neighboring penguins with similar vertical (y) positions show correlated steps in the horizontal (x) direction. The speed of the propagating wave is indicated by the slope of the red line. (Credit: Daniel P. Zitterbart, Barbara Wienecke, James P. Butler, Ben Fabry. Coordinated Movements Prevent Jamming in an Emperor Penguin Huddle. PLoS ONE, 2011; 6 (6): e20260 DOI: 10.1371/journal.pone.0020260)

Keeping Warm: Coordinated Movements in a Penguin Huddle

ScienceDaily (June 2, 2011) — To survive temperatures below -50 ° C and gale-force winds above 180 km/h during the Antarctic winter, Emperor penguins form tightly packed huddles and, as has recently been discovered -- the penguins actually coordinate their movements to give all members of the huddle a chance to warm up.

Physicist Daniel P. Zitterbart from the University of Erlangen-Nuremberg, Germany, recently spent a winter at Dronning Maud Land in the Antarctic, making high-resolution video recordings of an Emperor penguin colony. Together with biophysicist Ben Fabry from Erlangen University, physiologist James P. Butler from Harvard University, and marine biologist Barbara Wienecke from the Australian Antarctic Division, they found that penguins in a huddle move in periodic waves to continuously change the huddle structure. This movement allows animals from the outside to enter the tightly packed huddle and to warm up.
The results have now been published in the journal PLoS ONE.
The survival techniques of Emperor penguins have long intrigued scientists. One unresolved question was how penguins move to the inside of a huddle when the animals stand packed so tightly that no movement seems possible. Daniel P. Zitterbart and his team discovered that penguins solve this problem by moving together in coordinated periodic waves. This was observed by tracking the positions of hundreds of penguins in a colony for several hours. The periodic waves are invisible to the naked eye as they occur only every 30-60 seconds and travel with a speed of 12 cm/s through the huddle. Although small, over time they lead to large movements that are reminiscent of dough during kneading. The authors compare the formation of a huddle to "colloidal jamming" and the periodic waves to a "temporary fluidization." "Our data show that the dynamics of penguin huddling is governed by intermittency and approach to kinetic arrest in striking analogy with inert non-equilibrium systems, including soft glasses and colloids."
Daniel P. Zitterbart is currently developing a remote-controlled observatory to study penguins all year round. He hopes to witness the reversal of the dramatic decline in penguin colony sizes that is occurring in all areas of the Antarctic.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Public Library of Science, via EurekAlert!, a service of AAAS.

Journal Reference:

Daniel P. Zitterbart, Barbara Wienecke, James P. Butler, Ben Fabry. Coordinated Movements Prevent Jamming in an Emperor Penguin Huddle. PLoS ONE, 2011; 6 (6): e20260 DOI: 10.1371/journal.pone.0020260

Public Library of Science (2011, June 2). Keeping warm: Coordinated movements in a penguin huddle. ScienceDaily. Retrieved June 3, 2011, from http://www.sciencedaily.com /releases/2011/06/110601171614.htm

Online Lecture

2011-05-26T06:35:00.000-07:00

Click here to watch the lecture from the U of NC: Fossil Penguins--A 60 Million Journey from Wings to Flippers

New Paper on Kaiika Maxwelli Published

2011-05-26T06:33:00.000-07:00

Kaiika maxwelli, a new Early Eocene archaic penguin (Sphenisciformes, Aves) from Waihao Valley, South Canterbury, New Zealand

New Zealand Journal of Geology and Geophysics

Volume 54, Issue 1, March 2011, Pages 43 - 51

Authors:RE Fordyce^a; DB Thomas^a

DOI: 10.1080/00288306.2011.536521

Abstract

Kaiika maxwelli is a new species of archaic fossil penguin from the Kauru Formation (Waipawan-Mangaorapan, Early Eocene) of the southern Canterbury Basin, Waihao River, South Canterbury, New Zealand. Kaiika maxwelli is represented by a well-preserved large and robust humerus, in which the broad m. scapulotricipitalis tendon sulcus, sigmoidal shaft and vestigial supracondylar process are similar to those of the basal penguin Waimanu, but differs from Waimanu and other penguins by having a deeply incised ventral tubercle and a smoothly curved profile of the deltoid crest and head. Humeral length suggests a body length of 1.3 m comparable to that of an emperor penguin, indicating that large penguins lived at a time of global warmth. This is the first significant fossil penguin named from pre-Bortonian (Middle Eocene) strata of the southern Canterbury Basin. Kaiika maxwelli is only the seventh species of fossil penguin reportedly older than Middle Eocene.

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China Fossil Shows Bird, Crocodile Family Trees Split Earlier Than Thought

2011-05-20T10:16:00.000-07:00

This is a reconstruction of X. sapingensis, based on the fossil. (Credit: Sterling Nesbitt)

ScienceDaily (May 19, 2011) — A fossil unearthed in China in the 1970s of a creature that died about 247 million years ago, originally thought to be a distant relative of both birds and crocodiles, turns out to have come from the crocodile family tree after it had already split from the bird family tree, according to research led by a University of Washington paleontologist.

The only known specimen of Xilousuchus sapingensis has been reexamined and is now classified as an archosaur. Archosaurs, characterized by skulls with long, narrow snouts and teeth set in sockets, include dinosaurs as well as crocodiles and birds.

The new examination dates the X. sapingensis specimen to the early Triassic period, 247 million to 252 million years ago, said Sterling Nesbitt, a UW postdoctoral researcher in biology. That means the creature lived just a short geological time after the largest mass extinction in Earth's history, 252 million years ago at the end of the Permian period, when as much as 95 percent of marine life and 70 percent of land creatures perished. The evidence, he said, places X. sapingensis on the crocodile side of the archosaur family tree.

"We're marching closer and closer to the Permian-Triassic boundary with the origin of archosaurs," Nesbitt said. "And today the archosaurs are still the dominant land vertebrate, when you look at the diversity of birds."

The work could sharpen debate among paleontologists about whether archosaurs existed before the Permian period and survived the extinction event, or if only archosaur precursors were on the scene before the end of the Permian.

"Archosaurs might have survived the extinction or they might have been a product of the recovery from the extinction," Nesbitt said.

The research is published May 17 online in Earth and Environmental Science Transactions of the Royal Society of Edinburgh, a journal of Cambridge University in the United Kingdom.
Co-authors are Jun Liu of the American Museum of Natural History in New York and Chun Li of the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, China. Nesbitt did most of his work on the project while a postdoctoral researcher at the University of Texas at Austin.

The X. sapingensis specimen -- a skull and 10 vertebrae -- was found in the Heshanggou Formation in northern China, an area with deposits that date from the early and mid-Triassic period, from 252 million to 230 million years ago, and further back, before the mass extinction.

The fossil was originally classified as an archosauriform, a "cousin" of archosaurs, rather than a true archosaur, but that was before the discovery of more complete early archosaur specimens from other parts of the Triassic period. The researchers examined bones from the specimen in detail, comparing them to those from the closest relatives of archosaurs, and discovered that X. sapingensis differed from virtually every archosauriform.

Among their findings was that bones at the tip of the jaw that bear the teeth likely were not downturned as much as originally thought when the specimen was first described in the 1980s. They also found that neural spines of the neck formed the forward part of a sail similar to that found on another ancient archosaur called Arizonasaurus, a very close relative of Xilousuchus found in Arizona.

The family trees of birds and crocodiles meet somewhere in the early Triassic and archosauriforms are the closest cousin to those archosaurs, Nesbitt said. But the new research places X. sapingensis firmly within the archosaur family tree, providing evidence that the early members of the crocodile and bird family trees evolved earlier than previously thought.
"This animal is closer to a crocodile, but it's not a crocodile. If you saw it today you wouldn't think it was a crocodile, especially not with a sail on its back," he said.

The research was funded by the National Science Foundation, the Society of Vertebrate Paleontology, the American Museum of Natural History and the Chinese Academy of Sciences.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of Washington. The original article was written by Vince Stricherz.

University of Washington (2011, May 19). China fossil shows bird, crocodile family trees split earlier than thought. ScienceDaily. Retrieved May 20, 2011, from http://www.sciencedaily.com /releases/2011/05/110518151822.htm

Penguins' Oxygen Trick: How They Survive Deep Dives

2011-05-13T13:38:00.000-07:00

Jennifer Welsh, LiveScience Staff Writer

Date: 12 May 2011

An Emperor penguin dives through a hole into the water below Antarctica's McMurdo Sound sea ice.
CREDIT: Emily Stone, National Science Foundation

View full size image

Penguins are the acrobatic athletes of the seas, and they can keep diving for long periods of time because they have exquisite control over how and when their muscles use oxygen, new research indicates.

The penguins can switch between two modes of oxygen use — either starving their muscles or giving them an extra shot of oxygen to keep them working — to achieve their amazing dives.
"It appears that there's a little bit of plasticity or variability in what they do when they are diving," said study researcher Cassondra Williams of the University of California in San Diego. "It's much more complicated than we thought." [Infographic: The Ocean's Deepest Divers]

Emperor penguin jumping out of an ice hole.
CREDIT: Cassondra Williams

View full size image

Emperor Penguins in the ice.
CREDIT: Paul Ponganis

View full size image

To figure out how penguins survive deep dives on a single breath of air, the researchers designed special probes to monitor the levels of oxygen in the penguins' muscles during their dives off McMurdo Sound, Antarctica. The results are based on three emperor penguins and 50 dives, which ranged from 23 to 210 feet (7 to 64 meters) in depth, which lasted from 2.3 to 11.4 minutes.

"They have two different patterns they can opt for while they are diving," Williams told LiveScience. "In one, they appear to cut off blood flow completely to the muscle, leaving it to rely on its own supplies, which leaves the blood oxygen for the rest of the body, like the brain and the heart."

In other dives, the researchers saw a plateau after the initial oxygen drop. They believe that the penguin is selectively sending extra oxygen from the blood into the muscles, so they don't get tired. They can only do this for a limited time, though, until blood oxygen levels become too low for the rest of the body. Eventually the penguins need to come up for air.

Cutting off the oxygen supply to the muscles forces them to start making energy using "anaerobic" respiration, which is done without oxygen. It has a downfall, though; it produces a byproduct called lactic acid that can be toxic in high doses.

If the penguins let the lactic acid accumulate in their muscles, it takes longer to recuperate after a long dive, the researchers believe. This may be why on some dives the penguins send extra oxygen. For example, an extra oxygen shot might be beneficial if the penguins are taking

Emperor Penguin on the ice
CREDIT: Cassondra Williams

View full size image

several dives during a short stint to, say, chase down a school of fish and don't want to lose the feeding opportunity while they spend additional time on the ice recuperating.
"They don't want to hit their aerobic limit and accumulate lactic acid, but it's not clear how or why they do that," Williams said.

The study was published May 12 in the Journal of Experimental Biology.

Source

Why Global Warming Spells Disaster For Adélie Penguins (VIDEO)

2011-05-12T09:29:00.000-07:00

by: Kristina Chew

The Western Antarctic Peninsula is one of the most rapidly warming areas on the earth: In just the past half-century, its temperatures have risen by 10.8 degrees Fahrenheit. Adélie penguins rely on the ice to live and global warming is taking its toll on their numbers, though not exactly in ways one might think.

Indeed, Adélie penguin colonies on the Antarctic Peninsula, on the northern edge of Antarctica, have declined by 90 percent, and the only colony of emperor penguins that once lived there is now extinct. But it turns out that elsewhere, specifically in the Ross Sea, a southern extension of the Pacific Ocean, Adélie colonies have been growing significantly, as winter sea ice cover grows there.

Indeed, climate change has benefited penguins in some ways, as the New York Times observes:

...in the Ross Sea a reverse trend is occurring: Winter sea ice cover is growing, and Adélie populations are actually thriving. The Cape Royds colony grew more than 10 percent every year, until 2001, when an iceberg roughly the size of Jamaica calved off the Ross Sea ice shelf and forced residents to move 70 kilometers north to find open water. (The iceberg broke up in 2006, and the colony of 1,400 breeding pairs is now recovering robustly.) Across Ross Island, the Adélie colony at Cape Crozier -- one of the largest known, with an estimated 230,000 breeding pairs -- has increased by about 20 percent.

Climate change has created a paradise for some pack ice penguin colonies and a purgatory for others, but the long-term fate of all Adélie and emperor penguins seems sealed, as relentless warming eventually pulls their rug of sea ice out from under them. Some scientists attribute the recent sea ice growth in the Ross Sea to the persistent ozone hole, a legacy of the human use of chlorofluorocarbons that cools the upper atmosphere over the continent, increasing the temperature difference with the lower atmosphere and equator, and over the last 30 years has delivered significantly brisker westerly winds in the summer and autumn. The warming of Earth's middle latitudes is having a similar effect, increasing that temperature difference and sending stronger winds that push sea ice off the coast and expose pockets of open water, called polynyas, that give nesting Adélie penguins easier access to food.

Other factors including consumers' taste for Chilean sea bass have also helped the Ross Sea penguins' survival. Fishing fleets and a fishery in the Ross Sea have encroached on the last refuge of the fish, lessening the Adélie penguins' competition for food.

Despite this, the fate of the penguins seems sealed. As the boundary of the sea ice retreats south, the penguins' chances for survival diminishes. Global warming has also had a drastic effect on the food chain: A recent study in the Proceedings of the National Academy of Sciences has found that the warmer temperatures are killing off as much as 80 percent of the phytoplankton that grow under ice floes and the krill, a staple of the penguin diet.

Further, temperatures are rising in the Ross Sea: The average summer temperature at McMurdo Station, the American research base on Ross Island, has gone up 2.7 degrees Fahrenheit in the past 30 years, which is more than the global average. As the ice pack melts, the Ross Sea penguins will have no choice but to "shift their range farther south toward the pole."

David Ainley, an ecologist with the consulting firm H. T. Harvey and Associates who has been studying Ross Sea penguins for 40 years, notes that the penguins "appear to need light -- if only twilight -- to forage and navigate, and as comfort against predators." As the Adélie penguins have to go further south as the pack ice retreats, they may face extinction not only because their habitat is gone, but because of an "unshakable fear of darkness" -- because they find themselves living in a dark part of the world far from where they once made their colonies.

This video shows Adélie penguins on Ross Island, their home for the time being.

Source

HAPPY WORLD PENGUIN DAY!

2011-04-25T10:07:00.001-07:00

Each year, on or about the 25th of April, the Adelie penguins of Ross Island leave their brooding grounds and swim to their winter sanctuary northwest of the Balleny Islands. Some decided to mark the occasion by including all penguins and dubbing the day World Penguin Day.

Most penguins do participate in migratory habits. Why they favor some places more than others as their destination is the current work of biologists. Current belief is that the Adelies favor a place that has more pack ice, thereby providing more protection. This appears to be true, as the Davis Station Adelies migrate north, then west, staying close to the Antarctic continent. Also, Antarctica's days become much shorter and the Adelies do not feed well in the dark. Traveling north, these birds have longer days in order to fish and feed.

Other penguins migrate, as well. The Magellanic penguins of South America travel to Mar del Plata, where usually there is more food and less harsh conditions; however, in the past few years, the Magels have suffered many losses due to inadequate food. The Falkland Island Rockhopper Penguins have traditionally migrated to coastal South America, and the northernmost of the colonies favored the areas along the Patagonian Shelf. The Macaronis stay in the sub-Antarctic area, mostly at sea, during their migration from their breeding grounds.

These are just a few instances of penguin migration; the point is that they do migrate and when they do, this action initiates the end of the breeding season and the beginning of a new life in the vast southern ocean for thousands of newly molted juveniles.

Welcome to your world, little guys. Bon voyage!!!

Prehistoric Penguin

2011-04-19T07:39:00.000-07:00

Posted Apr 18,2011

From left: Aptenodytes forsteri (Emperor penguin), Inkayacu paracasensis, and Eudyptula minor (Little penguin)

Nothing is black-and-white, it seems. Not even penguins. That’s what University of Texas paleontologist Julia Clarke found after unearthing 36-million- year-old remains in Peru’s Paracas National Reserve—the first penguin fossil ever found with evidence of feathers intact. Like its present-day relatives, Inkayacu paracasensis was a deft swimmer. Unlike them, it weighed more than a hundred pounds and sported a coat with ruddy feathers. Clarke’s team deduced the color last year after comparing tiny pigment packages called melanosomes from the fossilized plumage with those of living species. This part of coastal Peru has recently produced other big penguin finds. Clarke says the area could be key to painting the full picture of the birds’ evolution. For now, a touch of color has been applied. —Catherine Zuckerman

Art: Mauricio Antón. Photo: Julia Clarke, University of Texas at Austin. NGM Maps

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Birds Inherited Strong Sense of Smell from Dinosaurs

2011-04-14T07:00:00.000-07:00

Evolution in birds of the olfactory bulb, the part of the brain where smell information is processed, passing from a dinosaur (Bambiraptor) through early birds (Lithornis, Presbyornis) to a modern-day bird (pigeon). (Credit: Courtesy of WitmerLab at Ohio University)

ScienceDaily (Apr. 13, 2011) — Birds are known more for their senses of vision and hearing than smell, but new research suggests that millions of years ago, the winged critters also boasted a better sense for scents.

A study published April 12 by scientists at the University of Calgary, the Royal Tyrrell Museum and the Ohio University College of Osteopathic Medicine tested the long-standing view that during the evolution from dinosaurs to birds, the sense of smell declined as birds developed heightened senses of vision, hearing and balance for flight. The team compared the olfactory bulbs in the brains of 157 species of dinosaurs and ancient and modern-day birds.

The findings, published in the journal Proceedings of the Royal Society B, dispute that theory. The scientists discovered that the sense of smell actually increased in early bird evolution, peaking millions of years ago during a time when the ancestors of modern-day birds competed with dinosaurs and more ancient branches of the bird family.

"It was previously believed that birds were so busy developing vision, balance and coordination for flight that their sense of smell was scaled way back," said Darla Zelenitsky, assistant professor of paleontology at the University of Calgary and lead author of the research. "Surprisingly, our research shows that the sense of smell actually improved during dinosaur-bird evolution, like vision and balance."

In an effort to conduct the most detailed study to date on the evolution of sense of smell, the research team made CT scans of dinosaurs and extinct bird skulls to reconstruct their brains. The scientists used the scans to determine the size of the creatures' olfactory bulbs, a part of the brain involved in the sense of smell. Among modern-day birds and mammals, larger bulbs correspond to a heightened sense of smell.

"Of course the actual brain tissue is long gone from the fossil skulls," said study co-author Lawrence Witmer, Chang Professor of Paleontology at the Ohio University College of Osteopathic Medicine, "but we can use CT scanning to visualize the cavity that the brain once occupied and then generate 3D computer renderings of the olfactory bulbs and other brain parts."

The study revealed details of how birds inherited their sense of smell from dinosaurs.

"The oldest known bird, Archaeopteryx, inherited its sense of smell from small meat-eating dinosaurs about 150 million years ago," said François Therrien, curator of dinosaur palaeoecology at the Royal Tyrrell Museum and co-author of the study. "Later, around 95 million years ago, the ancestor of all modern birds evolved even better olfactory capabilities."

How well did dinosaurs smell, especially compared to modern animals? Although scientists haven't been able to make an exhaustive comparison, Witmer noted that the ancient beasts most likely exhibited a range of olfactory abilities. T. rex had large olfactory bulbs, which probably aided the creature in tracking prey, finding carcasses and possibly even territorial behavior, while a sense of smell was probably less important to dinosaurs such as Triceratops, he said.

The team was able to make some direct comparisons between the ancient and modern-day animals under study. Archaeopteryx, for example, had a sense of smell similar to pigeons, which rely on odors for a number of behaviors.

"Turkey vultures and albatrosses are birds well known for their keen sense of smell, which they use to search for food or navigate over large areas," says Zelenitsky. "Our discovery that small Velociraptor-like dinosaurs, like Bambiraptor, had a sense of smell as developed as turkey vultures and albatrosses suggests that smell may have played an important role while these dinosaurs hunted for food."

If early birds had such powerful sniffers, why do birds have a reputation for a poor sense of smell? Witmer explained that the new study confirms that the most common birds that humans encounter today -- the backyard perching birds such as crows and finches, as well as pet parrots -- indeed have smaller olfactory bulbs and weaker senses of smell. It may be no coincidence that the latter are also the cleverest birds, suggesting that their enhanced smarts may have decreased the need for a strong sniffer, he said.

Other authors on the article include Amanda McGee, a graduate student at the University of Calgary, and Ryan Ridgely, a research associate in the WitmerLab at Ohio University. The research was funded by grants to Zelenitsky from the Natural Sciences and Engineering Research Council of Canada and to Witmer and Ridgely from the U.S. National Science Foundation.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Ohio University, via EurekAlert!, a service of AAAS.

Journal Reference:

D. K. Zelenitsky, F. Therrien, R. C. Ridgely, A. R. McGee, L. M. Witmer. Evolution of olfaction in non-avian theropod dinosaurs and birds. Proceedings of the Royal Society B: Biological Sciences, 2011; DOI: 10.1098/rspb.2011.0238

Ohio University (2011, April 13). Birds inherited strong sense of smell from dinosaurs. ScienceDaily. Retrieved April 14, 2011, from http://www.sciencedaily.com /releases/2011/04/110412201724.htm

Penguins That Shun Ice Still Lose Big from a Warming Climate

2011-04-12T18:19:00.000-07:00

Chinstrap penguin. Although chinstrap penguins avoid feeding in icy habitats, sea ice provides the necessary environment for krill to reproduce. Increasing temperatures and reductions in sea ice have made conditions unfavorable to sustain ample populations of this food source. (Credit: © Rich Lindie / Fotolia)

ScienceDaily (Apr. 11, 2011) — Fluctuations in penguin populations in the Antarctic are linked more strongly to the availability of their primary food source than to changes in their habitats, according to a new study published online on April 11 in the Proceedings of the National Academy of Sciences. Funded in part by the Lenfest Ocean Program, this research indicates that species often considered likely "winners" of changing conditions, such as large-scale ice melting, may actually end up as the most vulnerable to the impacts of climate change.

The two penguin species of focus in the study rely on small shrimp-like creatures known as krill for their survival. A previous assessment in Nature of krill in the Southern Ocean suggests that their abundance has declined as much as 80 percent since the 1970s.

"For penguins and other species, krill is the linchpin in the food web. Regardless of their environmental preferences, we see a connection between climate change and penguin populations through the loss of habitat for their main food source," said Dr. Wayne Trivelpiece, lead author and seabird researcher of the National Oceanic and Atmospheric Administration's Antarctic Ecosystem Research Division. "As warming continues, the loss of krill will have a profound effect throughout the Antarctic ecosystem."

A 30-year field study of Adélie (ice-loving) and chinstrap (ice-avoiding) penguins shows that populations of both species in the West Antarctic Peninsula and Scotia Sea have declined by respective averages of 2.9 and 4.3 percent per year for at least the last 10 years. Some colonies have decreased by more than 50 percent. Lack of an abundant supply of krill has been particularly hard on fledgling penguins that must learn where to locate and how to catch the prey on their own, having never been at sea before. Data from the study suggest that fewer young penguins are surviving this transition to independence today than in previous years when these crustaceans were much more abundant.

Although chinstrap penguins avoid feeding in icy habitats, sea ice provides the necessary environment for krill to reproduce. Increasing temperatures and reductions in sea ice have made conditions unfavorable to sustain ample populations of this food source. The authors suggest that fishing for krill and increased competition among other predators also have made them less available to penguins.

"Penguins are excellent indicators of changes to the biological and environmental health of the broader ecosystem because they are easily accessible while breeding on land, yet they depend entirely on food resources from the sea. In addition, unlike many other krill-eating top predators in the Antarctic, such as whales and fur seals, they were not hunted by humans," said Dr. Trivelpiece. "When we see steep declines in populations, as we have been documenting with both chinstrap and Adélie penguins, we know there's a much larger ecological problem."

Adélie penguins, which feed in icy habitats, are also declining due to food shortages and shrinking habitat. They differ from chinstrap penguins, however, in that they have breeding populations outside of the western Antarctic, which makes them less vulnerable to the rapid warming in the Antarctic Peninsula region by comparison.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Pew Environment Group, via EurekAlert!, a service of AAAS.

Journal Reference:

Wayne Z. Trivelpiece, Jefferson T. Hinke, Aileen K. Miller, Christian S. Reiss, Susan G. Trivelpiece and George M. Watters. Variability in krill biomass links harvesting and climate warming to penguin population changes in Antarctica. Proceedings of the National Academy of Sciences, April 11, 2011 DOI: 10.1073/pnas.1016560108

Pew Environment Group (2011, April 11). Penguins that shun ice still lose big from a warming climate. ScienceDaily. Retrieved April 12, 2011, from http://www.sciencedaily.com /releases/2011/04/110411152535.htm

'Naked' Penguins Baffle Experts

2011-04-10T09:14:00.000-07:00

A researcher holds a featherless Magellanic penguin chick. (Credit: Jeffrey Smith)

ScienceDaily (Apr. 9, 2011) — Researchers from the Wildlife Conservation Society, the University of Washington, and other groups are grappling with a wildlife mystery: Why are some penguin chicks losing their feathers?

The appearance of "naked" penguins -- afflicted with what is known as feather-loss disorder -- in penguin colonies on both sides of the South Atlantic in recent years has scientists puzzled as to what could be causing the condition.

A study on the disorder appears in a recent edition of the journal Waterbirds. The authors of the paper are: Olivia J. Kane, Jeffrey R. Smith, and P. Dee Boersma of the Wildlife Conservation Society and the University of Washington; Nola J. Parsons and Vanessa Strauss of the South African Foundation for the Conservation of Coastal Birds; and Pablo Garcia-Borboroglu and Cecilia Villanueva of Centro Nacional Patagónico.
"Feather-loss disorders are uncommon in most bird species, and we need to conduct further study to determine the cause of the disorder and if this is in fact spreading to other penguin species," said Boersma, who has conducted studies on Magellanic penguins for more than three decades.

The feather-loss disorder first emerged in Cape Town, South Africa in 2006, when researchers for the South African Foundation for the Conservation of Coastal Birds (SANCCOB) first observed the disorder in African (or black-footed) penguins in a rehabilitation center. During that year, approximately 59 percent of the penguin chicks at the facility lost their feathers, followed by 97 percent of the chicks at the facility in 2007, and 20 percent of the chicks in 2008. Chicks with feather-loss disorder, it was discovered, took longer to grow to a size deemed suitable for release into the wild. The chicks eventually began growing new feathers.
One the other side of the South Atlantic, researchers from WCS and the University of Washington observed feather-loss disorder in the chicks of wild Magellanic penguins (closely related to African penguins) for the first time in 2007 in four different study sites along Argentina's coastline. Researchers also noted that while feathered chicks sought out shade in the hot midday sun, featherless chicks remained in the sun's glare. Several of the chicks with feather-loss disorder died during the study.

In both instances, penguin chicks with feather-loss disorder grew more slowly than feathered chicks. Featherless chicks were also smaller in size and weight than feathered chicks; both disparities were due to the increased energy spent in thermoregulation in the absence of an insulating coat of feathers and/or down. So far, the possible causes include pathogens, thyroid disorders, nutrient imbalances, or genetics.

"The recent emergence of feather-loss disorder in wild bird populations suggests that the disorder is something new," said Mariana Varese, Acting Director of WCS's Latin America and Caribbean Program. "More study of this malady can help identify the root cause, which in turn will help illuminate possible solutions."
"We need to learn how to stop the spread of feather-loss disorder, as penguins already have problems with oil pollution and climate variation," said Boersma. "It's important to keep disease from being added to the list of threats they face."

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Wildlife Conservation Society, via EurekAlert!, a service of AAAS.

Wildlife Conservation Society (2011, April 9). 'Naked' penguins baffle experts. ScienceDaily. Retrieved April 10, 2011, from http://www.sciencedaily.com /releases/2011/04/110408140924.htm

Abundance of Feathered Dinosaurs During Temperate Climate With Harsh Winters

2011-03-14T13:37:00.000-07:00

Fragment of a jaw bone of a ceratopsian dinosaur, Archaeoceratops, from the Lower Cretaceous (Gansu province, China). (Credit: Copyright Romain Amiot)

Chilly Times for Chinese Dinosaurs: Abundance of Feathered Dinosaurs During Temperate Climate With Harsh Winters

ScienceDaily (Mar. 13, 2011) — Dinosaurs did not always enjoy mild climates. New findings show that during part of the Early Cretaceous, north-east China had a temperate climate with harsh winters. They explain the abundance of feathered dinosaurs in fossil deposits of that period.

The discovery was made by an international collaboration coordinated by Romain Amiot of the Laboratoire de géologie de Lyon: terre, planètes et environnement (CNRS/ENS de Lyon/Université Lyon 1).

Their work is published in the Proceedings of the National Academy of Sciences.

It has long been thought that the climate of the Mesozoic, the age of the dinosaurs, was generally warm across the planet. However, a recent study challenges this theory. The work focuses on a region of north-east China where the Jehol fauna developed during part of the Early Cretaceous (between 125 and 110 million years ago). The fossils found in this deposit include many dinosaurs covered with filamentous structures similar to bird feathers (such structures can take on various forms, ranging from filaments, down and 'protofeathers' to true feathers). But is this feature due simply to excellent conditions of preservation or to the adaptation of such species to environmental conditions? Since these dinosaurs were unable to fly, several scientists have suggested that their feathers acted as thermal insulation.

A team of paleontologists from France, China, Japan and Thailand examined the issue and tried to determine the temperatures at that time. Teeth and bones from dinosaurs, mammalian reptiles, crocodiles, turtles and freshwater fish from fossil deposits containing the Jehol fauna were collected. This selection of samples was then completed by fossil remains from contemporary deposits in other regions of China, Japan and Thailand. The scientists analyzed the oxygen isotopic composition of each sample. They based their analysis on the principle that the average local air temperature determines the relative quantity of oxygen isotopes contained in the rainwater drunk by the animals. This isotope record is passed on and stored within the bones and teeth of animals as they grow. Since the oxygen contained in the mineralized tissue is preserved during fossilization, the researchers were able to reconstruct the prevailing air temperatures in the environment of Asian dinosaurs during the Early Cretaceous.

The results show that average temperatures in this period of the Early Cretaceous were very similar to those of today at equivalent latitudes (such as the climate in Beijing today). The Jehol fauna therefore lived in a cool temperate climate characterized by harsh winters during which cold-blooded reptiles (turtles and lizards) had to hibernate, whereas the down, feathers and fur of warm-blooded animals (mammals, birds and dinosaurs) enabled them to maintain sustained activity in winter. "These results do not prove in any way that feathers appeared because of their insulating characteristics. They show that feathers would have given the dinosaurs of the Jehol fauna a physiological advantage over their fellow animals with scales," points out Amiot, lead author of the paper and currently a CNRS researcher at the Laboratoire de géologie de Lyon (ENS de Lyon/Université de Lyon 1/CNRS).

This work helps us to better understand the Early Cretaceous period, of which there are few geological records, and sheds new light on existing theories about Earth at the time of the dinosaurs.
The laboratories involved are: Laboratoire de géologie de Lyon: terre, planètes et environnement (CNRS/Université Lyon 1/ENS de Lyon); Laboratoire de géologie de l'École normale supérieure (CNRS/ENS Paris); Institut de physique du globe de Paris (CNRS/UPMC/Université Paris Diderot); and the Institute of Vertebrate Paleontology and Paleoanthropology , Beijing, China.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by CNRS (Délégation Paris Michel-Ange).

Journal Reference:

R. Amiot, X. Wang, Z. Zhou, X. Wang, E. Buffetaut, C. Lecuyer, Z. Ding, F. Fluteau, T. Hibino, N. Kusuhashi, J. Mo, V. Suteethorn, Y. Wang, X. Xu, F. Zhang. Oxygen isotopes of East Asian dinosaurs reveal exceptionally cold Early Cretaceous climates. Proceedings of the National Academy of Sciences, 2011; DOI: 10.1073/pnas.1011369108

CNRS (Délégation Paris Michel-Ange). "Chilly times for Chinese dinosaurs: Abundance of feathered dinosaurs during temperate climate with harsh winters." ScienceDaily 13 March 2011. 14 March 2011 <http://www.sciencedaily.com /releases/2011/03/110311173104.htm>.

Fossil Bird Study Describes Ripple Effect of Extinction in Animal Kingdom

2011-03-10T12:25:00.000-08:00

Jessica Oswald, an NSF predoctoral fellow at the Florida Museum of Natural History on the UF campus, holds the mandible, or beak, of an extinct species of cowbird, Pandanaris convexa, recently discovered for the first time in Mexico. The bird has previously only been found at the Rancho La Brea fossil site in California and a site in Reddick, between Gainesville and Ocala in North Central Florida. Oswald is lead author of a new study in the March 8, 2011, print edition of the journal Palaeogeography, Palaeoclimatology, Palaeocology. The research shows the ripple effect throughout the animal kingdom caused by the extinction of large mammals 20,000 years ago, including the disappearance of a cowbird species. (Credit: Florida Museum of Natural History/UF photo by Kristen Grace)

ScienceDaily (Mar. 9, 2011) — A University of Florida study demonstrates extinction's ripple effect through the animal kingdom, including how the demise of large mammals 20,000 years ago led to the disappearance of one species of cowbird.

The study shows the trickle-down effect the loss of large mammals has on other species, and researchers say it is a lesson from the past that should be remembered when making conservation, game and land-use decisions today.

"There's nothing worse for a terrestrial ecosystem than the loss of large mammals -- and the loss of apex predators like sharks, tuna and other large fish will have the same negative impact on the oceans," said study co-author David Steadman, ornithology curator at the Florida Museum of Natural History on the UF campus. "We're seeing it with the loss of lions and elephants in parts of Africa, as well as in Florida with the decline of panthers. There's no question these losses will have a negative domino effect on our ecosystems."

The fossil study of eight songbird species from northern Mexico by Florida Museum ornithologists is currently available online and will appear in the March 8th print edition of the journal Palaeogeography, Palaeoclimatology, Palaeocology.

An extinct cowbird, Pandanaris convexa, is the most common bird found at the fossil site called Térapa, in Sonora, Mexico, about 150 miles south of Arizona. This is the first time fossils of the large bird, a member of the blackbird family, have been found in Mexico.

Finding the extinct cowbird at the fossil site was unpredictable and unexpected, according to Jim Mead, chair of the department of geosciences at East Tennessee State University, who has collected a variety of fossils at the site, including the birds used in the study. Mead described the findings at Térapa as "bizarre and exciting."
"The tropical environment is unusual because the site is so far from the coast," Mead said. "The fossil record also provides evidence animals migrated from north to south and, unexpectedly, from south to north."

The cowbird has previously only been found at the Rancho La Brea fossil site in California and a site in Reddick, between Gainesville and Ocala in North Central Florida. The study expands the bird's known range and creates new questions about whether it may have lived across the southern U.S.

"The extinct cowbird needed grasslands and these big mammals to survive," said lead author Jessica Oswald, a National Science Foundation predoctoral fellow at the Florida Museum. "Those two things play into each other because mega mammals maintain grasslands. They keep big trees from coming in and colonizing the areas because they graze, stomp and trample little saplings."

Like modern cowbirds, this species probably fed on seeds and insects large mammals exposed, Oswald said. The mammals included extinct species of ground sloth, mammoth, horse, tapir, camel and bison.
About 20,000 years ago, most of these large mammals went extinct, which lead to the extinction of scavengers like condors and vultures, as well as cowbirds, Steadman said. Extinctions, especially mass extinctions, can cause radical species loss and changes in species distribution.

"Big species can't exist in a vacuum, nor can smaller species," Steadman said. "When one piece of the puzzle goes extinct, there is no good way of predicting what sort of trickle-down effect, what kind of cascade effect that will have."

The study also confirms the area was once marshy grassland, possibly surrounded by a savanna near a river. Fossils of plants, reptiles and mammals of all sizes, and 31 species of birds other than songbirds have been recovered from the Térapa site over the past 10 years. Most of these species are found today in grasslands or wetlands, Steadman said.

Steadman and Oswald used the Florida Museum's more than 24,000 skeletal specimens of birds to identify the Mexican fossils.

Songbirds make up more than 50 percent of the world's living bird species, but the fossil record is poorly developed, especially in Central and South America. Oswald said this study helps build the fossil record of songbirds in Mexico.

Finding bird fossils, as well as bones of other small animals, is a time-consuming and labor-intensive process. Sediment is placed in a fine mesh sieve and water is used to remove dirt and debris from the bones.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of Florida. The original article was written by Leeann Bright.

Journal Reference:

Jessica A. Oswald, David W. Steadman. Late pleistocene passerine birds from Sonora, Mexico. Palaeogeography, Palaeoclimatology, Palaeoecology, 2011; 301 (1-4): 56 DOI: 10.1016/j.palaeo.2010.12.020

University of Florida. "Fossil bird study describes ripple effect of extinction in animal kingdom." ScienceDaily 9 March 2011. 10 March 2011 /releases/2011/03/110307124959.htm>.

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Fittest Adélie penguins appear to sustain colony populations

2011-03-05T08:13:00.000-08:00

Photo Credit: Jean Pennycook

Adélie penguins squabble at the Cape Royds colony on Ross Island. Scientists studying the population dynamics of these seabirds for the last 15 years have noted some "super breeders" seem to be consistently successful in producing chicks that reach adulthood.

Super breeders

By Peter Rejcek, Antarctic Sun Editor

Posted February 18, 2011

For 15 years, U.S. researchers in Antarctica have watched the ebb and flow of Adélie penguin colony populations around the Ross Sea, recording the births and deaths, and the lives in between, of the continent’s iconic seabird in order to understand the patterns.

They’ve observed the large-scale changes over the summer seasons that have seen some colonies balloon to historic numbers, while at least one has plummeted to a near-record low. [See previous article: After the icebergs.] Now the scientists are focusing on why some individuals within the colonies are more successful than others in terms of foraging and breeding success.

Understanding the factors that determine which birds are better suited for the Darwinian dance of life can help the researchers predict how the penguins may fare in the future as climate change re-writes the script for survival.

“We’re getting a much better feeling with how individuals can cope with different scenarios,” said Grant Ballard , his face burnished nearly scarlet from the sun and wind of an Antarctic summer at Cape Crozier on Ross Island, home to one of the largest Adélie penguin colonies in the world.

Ballard and his co-principal investigators, David Ainley , an ecologist with H.T. Harvey and Associates in California, and Katie Dugger at Oregon State University , are at the start of a new five-year grant from the National Science Foundation that takes a bottom-up approach, focusing on individual capability, to learn how large populations will evolve and adapt over time.

Ainley said only about 20 percent of a given colony sustains the population consistently. More birds will breed successfully in “easy” years — when the journey across the sea ice from the rocky islands where the penguins nest to the open ocean where they forage is short.

But in tougher years, when the sea ice extends so far that the energy required to forage and feed their young causes many to fail, a special “breed” of penguin somehow manages to fledge their chicks to adulthood.

Photo Credit: Jean Pennycook

A healthy, fat penguin chick.

Photo Credit: Jean Pennycook

A penguin guards its nest.

“We found these super-breeders are much better foragers. They dive deeper; they have a shorter recovery period at the surface between dives. They bring back more food,” said Ainley, who first worked with the Ross Sea penguins in the 1970s as a PhD student.

Is it just a matter of genetics — a matter of being faster and stronger? Or does age and experience have anything to do with success?

It’s probably both, according to Ballard. The pattern the researchers have detected so far suggests that age and experience count, but older doesn’t necessarily equate to breeding success.

“There does seem to be variability at the individual level,” said Ballard, a staff scientist at PRBO Conservation Science in California.

For each of the last 15 summers at Cape Crozier, the penguin team has banded 1,000 new adults, so the researchers have a large pool of known-age birds that they track. Most nest at a site called Area M, home to about 20,000 of the estimated 230,000 breeding pairs spread across about 5 kilometers of the moraines on the lower slopes of Mount Terror.
Still, not all the birds cooperate, so Ballard and his colleagues hike the length and breadth of the colony at least once a week to locate the stragglers. They randomly select “super-breeders” and their ordinary cohorts for putting on time-depth recorders.

The compact instruments, painlessly taped on the lower back of the animal, provide data on how deep and how long a penguin dives on a foraging trip. A simple V-shape dive means the critter likely came up with an empty stomach. A distinctive wiggle at the bottom of the dive signals success.

“There are some individuals that always have the biggest chicks, and they’re always in the colony,” Ballard said. In other words, the super-breeders get in, get out and get back to the colony more efficiently. That means not only more food, more often for its chicks, but more protection against predatorial skuas because super-breeders spend less time away from the nest.

Eventually, the team wants to determine to what extent the abilities of super-breeders are passed on to succeeding generations. Is it hereditary? Or are there enough “easy” years when the gene pool becomes flooded, diluted by the genes of the other 80 percent?

“There’s still a huge amount of mystery when it comes down to it,” Ballard said.

Dugger noted that one can’t be into instant gratification in this business of demographic research. “We get one data point each year with a huge amount of effort,” she said.

NSF-funded research in this story: David Ainley, H.T. Harvey and Associates, Award No. 0944411 ; Grant Ballard, PRBO, Award No. 0944141 ; and Katie Dugger, Oregon State University, Award No. 0944358 .

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Changes in Ross Sea environment, fishery cause demographic shift in species

2011-03-05T08:06:00.000-08:00

Photo Credit: Nate Biletnikoff/Antarctic Photo Library

Adélie penguins float on an iceberg near Cape Crozier on Ross Island. Cape Crozier is home to one of the largest colonies of Adélies in the world. Scientists hypothesize its growth may, in part, be to shifts in the number of marine species in the Ross Sea due to pressures caused by a fishery that captures commercially available Chilean sea bass.

Population pressures

By Peter Rejcek, Antarctic Sun Editor

Posted February 18, 2011

The penguin colony at Cape Royds on Ross Island in Antarctica is the southernmost breeding ground for any penguin in the world — seen by humans as an extreme place to raise chicks.

Still, the colony had grown to about 4,200 breeding pairs before 2001, one of the highest populations for that location in historic records dating back to 1907, according to David Ainley , senior ecologist at a SF Bay Area ecological consulting firm, H.T. Harvey and Associates . Ainley is the principal investigator for a long-term project trying to understand factors behind the population dynamics and trends at Royds and other colonies in the Ross Sea region.

But then giant icebergs calved off the Ross Ice Shelf in 2000, locking in hundreds of additional square kilometers of sea ice beginning in 2001. That meant a long trek for the Adélies from Cape Royds to the open ocean to get food for their chicks.

The population crashed. In 2006, the dam of ice broke and open water appeared again farther south. Two years later, when The Antarctic Sun checked in with Ainley, the Royds colony was just “treading water,” though enjoying good reproductive success. He thought the young adults would start returning to the colony in the foreseeable future.

And, indeed, for the second straight year, there was a large influx of young birds (three to four years old) at the end of the breeding season. Ainley said that while last year’s “invasion” of young adults did contribute to the breeding population this year, the colony was further diluted in 2010 by the late arrival of former breeders.
That left the breeding population at Royds at about 1,400 pairs, its lowest total since 1970, when it started to recover from uncontrolled tourism in the 1960s. Since then, the location of the colony has been an Antarctic Specially Protected Area , a designation under the Antarctic Treaty system that controls access to the site.

One factor in the decline may be the lack of younger birds returning to the colony to try breeding, according to Ainley. Young adults will often set up nests around the exterior of the colony as they “practice” breeding skills.

Photo Credit: Melanie Connor/Antarctic Photo Library

Scientist Art DeVries weighs an Antarctic toothfish in November 2002, four years before the Ross Sea fishery began.

Photo Credit: Donald LeRoi/Antarctic Photo Library

A scientist observes killer whales in the Ross Sea. Researchers have reported that occurrence frequency of orcas has dropped since a fishery moved into the region.

Those nests serve as a sort of shield for the successful breeders against predatorial skuas, a clever species of seabird that uses all manner of trickery to steal chicks and eggs. A favored ploy is for the skuas to operate in pairs: One pulls an adult’s tail, while its partner pulls an egg out of the nest while the penguin is distracted.

“The skuas are just having a field day. They’re like people: They don’t manage their resources very well; they don’t believe in rainy days,” Ainley said. “There’s actually large areas of Royds now that are totally vacant of penguin nests where there were nests before the iceberg.”

Fishy business

Meanwhile, other colonies in the region have grown tremendously, buoyed to a limited extent by penguins from Royds that abandoned their colony in the tough iceberg years.

Cape Crozier on Ross Island now boasts an estimated 230,000 breeding pairs, which could place it at the top of the list for the largest Adélie colony in the world. That’s up by nearly 50,000 breeding pairs in the last decade before the icebergs moved in. On nearby Beaufort Island, the colony has expanded from 40,000 to 55,000 breeding pairs.
But immigration from Royds cannot explain the rapid expansion of these other colonies, Ainley said.

Instead, he suspects that the Adélie populations are skyrocketing because they face less competition from another predator in the Ross Sea food web — the Antarctic toothfish (Dissostichus mawsoni), known to seafood consumers as Chilean sea bass. Both prey extensively on the Antarctic silverfish (Pleuragramma antarcticum) in waters over the Ross Sea continental shelf.

Ainley believes a toothfish fishery that operates in the Ross Sea — authorized by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) , which oversees fishing in the Southern Ocean — may be taking too big of a bite out of the D. mawsoni population.

“Just as when thousands of food-competing Antarctic minke whales were removed from the wintering area of Ross Sea penguins during the 1970s, Adélies are exhibiting a spurt of colony growth not easily explained by climate change,” Ainley said.

He and others have argued in the scientific literature that too little is known about the life history of the toothfish, a late-maturing, slow-growing, long-lived species that can grow up two meters long. He said it was unwise to allow the fishery to operate without learning more about what the limits may be to its footprint.
The fishery began in the 1996-97 austral summer. In less than a decade, scientists who had been successfully capturing and releasing Antarctic toothfish in McMurdo Sound for research since the 1970s could no longer find any specimens.

Concurrently, Ross Sea killer whales, which prey on toothfish, have decreased in occurrence frequency, according to a paper in 2009 in the journal Aquatic Mammals by Ainley, Grant Ballard and Silvia Olmastroni. A staff scientist at PRBO Conservation Science , Ballard is a co-principal investigator on the Ross Sea penguin population dynamics study with Ainley and Katie Dugger at Oregon State University (and collaborators Phil Lyver and Melanie Massaro of Landcare Research New Zealand).

Ainley noted that silverfish-eating emperor penguins (Aptenodytes forsteri) have also increased their presence in McMurdo Sound. “[It’s] the only part of the Ross Sea where these sorts of systematic observations are possible owing to the logistics available from the U.S. Antarctic Program ,” Ainley said.
Is the Ross Sea fishery to blame for the apparent shift in populations of whales, penguins and Antarctic toothfish?

“You can’t discount it, even though there are a lot of people who want to,” said Ainley, who is concerned that the fishery may skew data collected by researchers such as himself studying the effects of climate change on the marine ecosystem.

“You’re either studying climate change or you’re studying fish depletion, so what are you going to study?” he asked.

NSF-funded research in this story: David Ainley, H.T. Harvey and Associates, Award No. 0944411 ; Grant Ballard, PRBO, Award No. 0944141 ; and Katie Dugger, Oregon State University, Award No. 0944358 .

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S. Rockhopper Gains Protection from Salazar

2011-02-24T17:51:00.000-08:00

Southern rockhopper penguins

Photo: mbz1 GNU Free lic.

February 23rd, 2011 8:58 pm ET
Jean Williams
Environmental Policy Examiner

As a result of pressure from the environmental organizations, Center for Biological Diversity and Turtle Island Restoration Network, the Interior Department announced on Tuesday that New Zealand-Australia populations of southern rockhopper penguin would finally get listed as a “threatened” species for protection under the Endangered Species Act.The listing followed a legal settlement with the two organizations.Although it is not an “endangered” listing, it will increase funding for research and conservation and additional oversight to federal activities that could result in harm to the existing rockhopper population.

“These hardy penguins survive on remote, stormy, sub-Antarctic islands in the Southern Ocean, practically at the edge of the world, and yet they may not survive climate change,” said Catherine Kilduff, an attorney at the Center, which first petitioned to protect the rockhoppers and 11 other penguin species in 2006. “Endangered Species Act protections can begin to address this threat.”

According to the Center for Biological Diversity press release, Rockhopper penguins, named for the way they hop from boulder to boulder, are widespread — breeding on islands off South America, Africa, Australia and New Zealand — but the penguins listed today have declined by more than 90 percent since the early 1940s. Changes to the marine environment, such as increases in sea-surface temperatures and reduced prey availability, are the primary threat to these colonies.

“These penguins have adapted to an inhospitable environment over hundreds of years, but the combination of ocean warming and commercial fishing may prove to be too much,” said Todd Steiner, biologist and executive director of TIRN. “Through this listing, the government is acknowledging that our oceans are sick and taking a first step to protect penguins and their watery world.”

The Center predicts that by mid-century, if greenhouse gas emissions remain on their current trajectory, climate change will commit one-third of the world’s animal and plant species to extinction. The threatened southern rockhopper penguin joins six other recently protected penguins: the African penguin, the Humboldt penguin of Chile and Peru and four other New Zealand penguins (the yellow-eyed, white-flippered, Fiordland crested and erect-crested).Interior Department Secretary Ken Salazar has a dismal record on listing species for ESA protection and rarely does so, without pressure from conservation groups.More information on the plight of the penguins

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Thank you Center for Biological Diversity!!!!

Southern Rockhopper Penguins Listed as Threatened Species; Climate Change Protections Needed

2011-02-23T07:17:00.000-08:00

For Immediate Release, February 22, 2011

Contacts:

Catherine Kilduff, Center for Biological Diversity, (415) 644-8580
Todd Steiner/Teri Shore, Turtle Island Restoration Network, (415) 663-8590 x 103/104

Southern Rockhopper Penguins Listed as Threatened Species; Climate Change Protections Needed

SAN FRANCISCO— The Interior Department announced today that the New Zealand-Australia populations of the southern rockhopper penguin, among the world’s smallest penguins, will be listed as threatened under the U.S. Endangered Species Act. The listing will raise awareness of the rockhoppers’ plight, increase research and conservation funds, and offer added oversight of U.S.-government-approved activities that could hurt the birds. It follows a legal settlement with the Center for Biological Diversity and Turtle Island Restoration Network (TIRN) over delays in protecting the penguin.

“These hardy penguins survive on remote, stormy, sub-Antarctic islands in the Southern Ocean, practically at the edge of the world, and yet they may not survive climate change,” said Catherine Kilduff, an attorney at the Center, which first petitioned to protect the rockhoppers and 11 other penguin species in 2006. “Endangered Species Act protections can begin to address this threat.”

“These penguins have adapted to an inhospitable environment over hundreds of years, but the combination of ocean warming and commercial fishing may prove to be too much,” said Todd Steiner, biologist and executive director of TIRN. “Through this listing, the government is acknowledging that our oceans are sick and taking a first step to protect penguins and their watery world.”

By mid-century, if greenhouse gas emissions remain on their current trajectory, climate change will commit one-third of the world’s animal and plant species to extinction. The threatened southern rockhopper penguin joins six other recently protected penguins: the African penguin, the Humboldt penguin of Chile and Peru and four other New Zealand penguins (the yellow-eyed, white-flippered, Fiordland crested and erect-crested).
Rockhopper penguins, named for the way they hop from boulder to boulder, are widespread — breeding on islands off South America, Africa, Australia and New Zealand — but the penguins listed today have declined by more than 90 percent since the early 1940s. Changes to the marine environment, such as increases in sea-surface temperatures and reduced prey availability, are the primary threat to these colonies.

The threatened penguins breed on Macquarie, Campbell, Auckland and Antipodes islands, which are ecologically and geographically unique as well as historically high-quality habitat. The Campbell Island southern rockhopper population was once one of the largest in the world, but has experienced the most severe declines.

For more information on penguins, please see: http://www.biologicaldiversity.org/species/birds/penguins/index.html.

The Center for Biological Diversity is a national, nonprofit conservation organization with more than 320,000 members and online activists dedicated to the protection of endangered species and wild places.

Turtle Island Restoration Network (TIRN) is an environmental organization working to protect and restore endangered marine species and the marine environment on which we all depend. Headquartered in California, with offices in Texas and Costa Rica, TIRN is dedicated to swift and decisive action to protect and restore marine species and their habitats and to inspire people in communities all over the world to join us as active and vocal marine species advocates. For more information, visit www.SeaTurtles.org and www.TIRN.net.

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Penguins: The luckiest birds alive

2011-02-23T07:08:00.000-08:00

Penguins' extraordinary ability to survive in the Antarctic is down to an accident of evolution - the heating system in their wings. Roger Dobson explains

Wednesday, 23 February 2011

REX FEATURES

A heat retaining adaptation in the birds' wings has ensured their survival

enlarge

Penguins may owe their survival in the coldest and most inhospitable place on earth to evolutionary chance during a period of global warming millions of years ago. Far from adapting to the cold in Antarctica, where temperatures can plunge below minus 60C and wind speeds reach in excess of 200mph, they have been able to thrive because of a form of central heating of the wings they evolved when the climate on Earth was hot.

New research shows that when the earth warmed up nearly 50 millions years ago, penguins evolved a wing heating system, a highly efficient heat exchanger.

The mechanism, which is so effective that the birds have to cool down after vigorous swimming in sub-zero waters, evolved to help the birds keep warm while foraging in ever deeper, ever cooler waters. "Penguins had a lucky break with the evolution of heat retention 49 million years ago, as it allowed them to survive the coming cold," says Dr Daniel Thomas of the University of Otago, New Zealand, who led the study. "The fossil evidence reveals that it evolved during a Greenhouse Earth interval.

"Its evolution is therefore unrelated to global cooling or development of polar ice sheets, but probably represents an adaptation to foraging beneath the surface in waters at temperate latitudes. As global climate cooled, the heat exchanger was key to the invasion of the much more demanding environments associated with Antarctic ice sheets. The climate has never been so hot as it was back then, nor has it been so cold as in recent millennia, and penguins have weathered it all. We are seeing a dramatic shift in climate, however, and it will be a true test for the thermal tolerances of penguins."

Penguins probably evolved from flying birds between 50 and 60 million years ago. Exactly why they lost the ability to fly is not known, but the dominant theory is that it was the survival trade-off for perfecting flight beneath the surface of the sea. It became more important to be able to dive and swim for food than to fly, so over time the birds lost the ability to fly, and wings became flippers.

The first penguins came some time after the Cretaceous-Tertiary or KT mass extinction event, around 65 million years ago when almost all the large vertebrates on Earth – dinosaurs, plesiosaurs, mosasaurs, and pterosaurs – suddenly became extinct for reasons that are still hotly debated.

After KT, climates warmed with temperatures peaking in the Eocene epoch, around 49 million years ago. Geochemical signals, telltale signs of how the earth once was, suggest that it was much warmer. Sea temperatures were around 25C, and the area around what is now Seymour Island in Antarctica, a major penguin habitat, was a balmy 15C, while parts of the now ice-covered region were subtropical. It has long been believed that penguins gradually adapted to increasingly cold conditions after the area became glaciated about 34 million years ago.

But the new research, by scientists from New Zealand, America and South Africa, based on analysis of modern penguins and of fossils dating back more than 60 million years, shows that the key anatomical change that was to become pivotal to survival in the extreme cold many years later occurred when global warming reached its peak, 49 millions years ago. In the study, the researchers examined the remains of several types of modern penguins, including the little penguin, yellow-eyed penguin, king penguin, and Humboldt penguin, all of which had died naturally.

Dissection of the birds showed that each had a major adaptation that allows penguins to forage in cold water, the humeral arterial plexus, a counter current vascular heat exchanger, or CCHE, that limits heat loss through the wing. The core body temperature of a penguin is around 38C. Although blubber and feathers offer some protection to the body, the large wings, with tightly attached skin and little insulation, have a huge surface area. Without protection, heat in the wing or flipper would be rapidly lost to the surrounding colder water or air with the threat of hypothermia and death. Heat is lost 20-30 times faster in water than in air.

The CCHE is an ingenious web of arteries and veins that stops this happening. Blood is pumped to the wings of birds through a single major artery, but in penguins there are up to five arteries, each of which runs alongside two or more veins. Blood in the arteries being pumped into the wing from the heart is much warmer than that in the veins which is returning from the wing extremities exposed to the cold. Heat from the arterial blood is given to the venous blood, and redirected back to the body instead of being lost to the ocean. It is so effective that penguins emerging from the sea often stick their wings out to the sides in order to cool them down.

But when did it evolve? The results of the dissections show that the presence of this heat exchanger mechanism requires grooves in the bones of the wings to carry the arteries, which should be detectable in fossils. The researchers looked at penguin fossils dating from 62 million years ago for signs of these grooves. In the early period birds there were none, but from around 49 million years ago they are present. At around the same time, other changes and adaptations were taking place that improved buoyancy in the water and reduced drag. Body size increased too, and a hydrofoil wing evolved.

But while all of these changes improved the penguins' abilities for long distance swimming and deep diving, there was a snag. While much of the land was now tropical or subtropical, temperatures in the sea had not increased as much and it was still very cold, and significantly cooler than penguin body temperature.

According to the researchers, it was these longer feeding excursions far from the shore, and spending long periods of time in cold waters, that led to the evolution of the heat exchanger.

Once equipped with the CCHE, the now flightless penguins were able to travel vast distances, and colonise new areas. And millions of years later, when the earth began to cool, the onboard heat exchanger meant the penguin was uniquely equipped for a successful invasion of icy Antarctic, an environment where it has walked, or waddled tall, ever since.

Ironically, there have been warnings that the penguin is at risk from the effects of global warming, including rising temperatures and a loss of sea ice, with a consequent reduction in nesting and breeding grounds, as well as a drop in food availability. "This is very interesting research and it suggests the heat exchanger is an adaptation to allow longer to be spent in the water," says Dr Jonathan Green, lecturer in marine biology at the University of Liverpool. "It is an adaptation which developed to promote foraging in warmer water and by coincidence proved to be helpful in cold waters and air temperatures. The same mechanism is employed in other parts of the penguin body, including the feet, which stops them freezing when they are in contact with ice.

"Our own research has shown that global warming is a threat. Only two of the 17 species of penguin breed on the Antarctic continent. The others live in the sub-Antarctic and temperature regions in South America, South Africa and Australasia. Our research in Australia has shown that temperature rises can cause problems for the penguins. A danger from global warming is that this overheating may lead them to abandoning breeding attempts, resulting in declining population numbers."

Huddling: The emperor's other way of warming up

Penguins keep warm on land by huddling.

Scientists have found that it is highly effective for keeping warm on land and can generate a tropical environment in one of the coldest environments on earth.

The emperor penguin breeds during the severe Antarctic winter, and the males have the job of incubation, which involves them being deprived of food for around 65 days.

But successful breeding requires a temperature of around 35C, and so to keep warm, the males huddle.

Researchers from the Scott Institute of Polar Research, who investigated what exactly happens inside huddles for the first time, showed that the birds spend an average of 38 per cent of breeding time huddling, with huddles lasting around 90 minutes. The birds moved around in the huddle so they all had access to the inner warmth.

Temperatures during tight huddling increased from 20C to 37.5C in less than two hours. "This complex social behaviour enables all breeders to get a regular and equal access to an environment which allows them to save energy and successfully incubate their eggs. Huddling behaviour of emperor penguins is a far more complex behaviour than previously described," say the researchers.

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How Dinosaurs Handed Down Their Fingers to Birds

2011-02-13T08:32:00.000-08:00

Wynne Parry LiveScience Senior Writer

Fri Feb 11

Birds are believed to be descended from dinosaurs, but some significant changes must have happened as they evolved from their ancestors. A new study involving baby chicks may help clear up a mystery of how one of those changes occurred -- how birds got their wing "fingers."
All four-limbed creatures, including dinosaurs, evolved from an ancestor that had five digits at the end of its limbs. These became flippers, wings, hands or paws, and some or all of the digits disappeared altogether in some cases.
Scientists think birds evolved from a group of meat-eating dinosaurs called maniraptors some 150 million years ago, during the Jurassic period. Modern birds have three digits in each of their wings, which means two digits in the forelimbs of these dinosaurs would have had to be lost during evolution.

A question of numbering

But which three digits survived? Paleontologists and developmental biologists have disagreed heartily on this. A proposal made in 1999, called the “frame shift” hypothesis, explained a discrepancy in the evidence, but not everyone accepted it.
The new study, conducted by researchers who transplanted cells from one part of a chick’s body to another, adds to the support for the hypothesis. The results of their study appear today (Feb. 10) in the journal Science.
If you number the digits so that digit 1 corresponds with our thumbs, digit 2 with our index fingers and so on, the fossil record shows that birds' wings evolved using digits 1, 2 and 3 of the dinosaur’s forelimbs.
However, in a bird embryo, the digits arise from the places on the limb bud associated with digits 2, 3 and 4. This conflict supported those who challenged whether birds were directly descended from dinosaurs.
In 1999, Günter Wagner and Jacques Gauthier of Yale University bridged the two factions by proposing that during development, digit 1 actually arose from the second position (where digit 2 should have arisen), and so on -- a frame shift.
"The great thing about the frame shift theory is it makes both things correct," said Ann Burke, an evolutionary morphologist at Wesleyan University in Connecticut, who was not involved in the current study. "Birds are dinosaurs, but developmentally the digits are 2, 3 and 4."

The new evidence

In the new study, Japanese researchers led by Koji Tamura of Tohoku University transplanted certain cells from the feet to the wings and vice versa of developing chicks. These cells are implicated in the growth of digit 4. The researchers found evidence that the last digit of the wing does not correspond to the last digit of the foot. This supports the theory that the wing, unlike the foot, does not have a digit 4, they said.Then the team mapped out digit development using cell-labeling techniques (enabling them to know where a certain cell ended up once it matured). They found that by 3.5 days of embryonic development, a shift occurs, causing cells in the progenitor region for digit 4 to move forward and grow into digit 3. The same shift occurs for the digits that become 1 and 2.
"I cannot tell you ‘why’ we have five digits and chickens have three digits, although I will be able to correctly tell you ‘how’ they have three digits whereas we have five digits," Tamura told LiveScience in an e-mail.
The findings accomplish two things, according to Tim Rowe, a professor of paleontology at the University of Texas at Austin who was not involved in the study.
First, "it pertains directly to this seeming conflict between paleontological records and developmental records. It shows in fact there is no inconsistency," said Rowe.
And second, it provides an excellent example of a shift in which one body part is transformed into another during embryonic development, he said.
"We are discovering part of the Holy Grail, which is the evolution of development, how the development of the limb changed during evolution of birds from their theropod ancestor," Rowe said.
This is not the first research to support the frame shift hypothesis, according to Wagner . "I think there is now enough data that shows that the frame shift actually happened," Wagner told LiveScience. "This is going a step further; it shows us the developmental mechanism."

Persistent skepticism

To determine the identity of the last digit in the chicks' "hands," the study used the development of the last digits in a five-digit mouse limb as a guiding model. This leaves Alan Feduccia, an evolutionary biologist at the University of North Carolina at Chapel Hill, skeptical of the results.
Feduccia, who wasn't involved in the study, is an opponent of the predominant scientific view that birds are descended from theropod dinosaurs (which include maniraptors). Rather, he believes birds and theropod dinosaurs share a common, earlier ancestor. This new study gives him no reason to change his mind.
"The experimental results seem to be very equivocal," Feduccia said, "because the bird hand is so highly modified that we don't know that same genetic mechanisms apply to digit identity."
The shift in digits just doesn't make sense, he said. "There is no imaginable selective advantage for such a shift -- in other words, why would it occur?"
But he is in the minority.
Wesleyan’s Burke has another issue with the frame shift theory; she believes renumbering the digits of the growing chicks is potentially misleading.
"The dinosaur ancestry of birds is absolutely sound and so well-supported that nobody disagrees with that, so just trying to change the digit numbers in living birds to conform to fossilized ancestry is unnecessary and eclipses important evolutionary change," she said.

Source

Little Blue Penguin Shows Its Colors

2011-02-09T10:34:00.000-08:00

>Little blue penguins are the world's smallest penguins, and are found on Australia and New Zealand. While they are not considered endangered, they are losing some habitat due to urban encroachment. Credit: Dreamstime.

Dapper Blue Penguin: Tux Is a Feathery First

By Jennifer Welsh, LiveScience Staff Writer
08 February 2011

: False-colored scanning electron micrograph of arrays of β-keratin nanofibres found in barbs of blue penguin (Eudyptula minor) feathers. Credit: Liliana D'Alba.

If these penguins look blue to you, it's not because they are down in the dumps. They have a special protein structure in their feathers that generates the blue color by reflecting light in a way that has never been seen in feathers before.

Lead author Matthew Shawkey of the University of Akron was surprised to find the new structures, which "shatter current dogma," Shawkey told LiveScience. "We found a previously undescribed way that birds make a non-iridescent blue color in feathers."

Shawkey found the structure in feathers of the blue penguin, a bird commonly found in Australia and New Zealand and also called the little, or fairy, penguin, awkwardly stands about a foot tall (30 cm) and weighs a little more than 2 pounds (about 1 kg). They have the traditional tuxedo look of penguins, though their feathers are a non-iridescent dark blue.

For the last 30 years only two ways of making a non-iridescent blue feathers were known, both which depend on holes in a spongy-like matrix of a protein called beta-keratin. The pores in the matrix trap and reflect light in the blue color range. "When I first looked at them [the feathers] I expected them to be one of these other two mechanisms," Shawkey said to LiveScience.

In the blue penguin feathers, the beta-keratin is aligned into parallel fibers, like a row of hairs. The alignment and size of the fibers scatters the light and reflects those in the blue pigment range. This is the first time this organizational structure has been seen to produce color in feathers.

"The mechanisms that produce structural coloration in animals is so little studied that I am not surprised at all that a new mechanism was found in penguins," Geoffrey Hill at Auburn University in Auburn, Ala., who was not involved in the study. "Shawkey and Prum are like the first Europeans who came ashore in North America and had a vast uncharted realm to explore."

Ancient pigments

The discovery was not only a surprise in itself but an unexpected find to Shawkey, who stumbled upon the odd structure during the course of another project. After some recent work reconstructing the color of ancient dinosaur feathers, Shawkey moved on to analyzing the color of some 35 million-year-old penguin feathers, which required his team to analyze the color-producing pigments and proteins in living penguins.

When his team took a look at what made the blue penguin's feathers blue, he was shocked. "These fibers were unexpected, they look totally different than anything we ever seen before," he told LiveScience.

The team looked at how these filaments scattered light and X-rays to determine what the structures look like and figure out how they were producing the blue color. They saw that the structure was highly organized; It looked a lot different than the spongy, disordered keratin structures that have been observed to create colors in feathers before.

The 160-nanometer keratin filaments lined up in an array that Shawkey describes as "a handful of uncooked spaghetti." They also saw that how the filaments were lined up would create a blue color reflection. Hundreds of the fibers line up side by side in the cells that make up the feather's barbs — the silky fibers that branch off of the quill.

"The significance lies in the realization that there are many ways to use nanostructures to produce blue color," Hill told LiveScience in an e-mail. "The research underscores that we should keep investigating structural coloration in diverse animals to see what other ingenious mechanisms natural selection has produced."

Evolving technologies

Beta-keratin is known to self-assemble fibers and Shawkey said that this parallel arrangement might have evolved from that ability of beta-keratin. If the structure does assemble itself, instead of needing a cellular scaffold, it could be easily manufactured. "There might be some interest in mimicking these for applications from things like cosmetics to fiber-optic cables," Shawkey told LiveScience. "If they are self- assembled it would be interesting because it would be cheap to manufacture them."

Shawkey also wonders if this organization somehow gives the penguin feathers special benefits, like additional strength or rigidity to withstand flying through the water, which is 1,000 times more viscous than the air birds normally fly through.

While this is the first time this sort of structural formation of blue color has been seen in feathers, a similar method of color production has been seen in blue skin of birds, though in that case the fibers are made up of collagen.

"Both beta-keratin and collagen have an innate tendency to self-assemble into fibers, so it makes sense that you would find these nanofibers made from both beta-keratin and collagen." The two structures seem to be an example of convergent evolution, when two structures evolve separately but use the same mechanism, he said.

Source

Paleontologist after more evidence that relatives of modern birds co-existed with dinosaurs

2011-02-01T17:14:00.000-08:00

Photo Credit: N. Adam Smith

Julia Clarke exposes a wing feature on a fossilized penguin specimen recovered from Peru. She and colleagues found evidence from fossils collected in Antarctica in the 1990s that at least one species related to modern birds lived at the same time as dinosaurs. She and a science team are headed to the Antarctic Peninsula in February 2011 in hopes of finding more fossils.

Winging it

By Peter Rejcek, Antarctic Sun Editor

Posted January 21, 2011

The theory that close relatives of modern birds once co-existed with non-avian dinosaurs before a mass extinction 65 million years ago had trouble flying with many paleontologists until about five years ago.

That was when a team of scientists announced that new data from fossils discovered in Antarctica in the 1990s by Argentine researchers offered evidence that at least one species related to modern birds shared the same space and time with dinosaurs. [See previous article: Antarctic bird nest?]

Reverse course

Sidebar:
Penguins of a feather

Antarctic bird nest?

Julia Clarke was the lead author of that Nature paper, with the bold title “First definitive fossil evidence for the extant avian radiation in the Cretaceous.” Now Clarke, an associate professor of paleontology at the Jackson School of Geosciences at the University of Texas in Austin , hopes to get her hands on additional material from Antarctica that will fill in more of the story about the early spread of all living birds.

Toward that purpose she’ll join a team of paleontologists headed to a group of islands off the Antarctic Peninsula early next year led by Ross MacPhee , with the American Museum of Natural History in New York . [See related article: Reverse course.]

The fossil hunters include dinosaur and mammal experts. “It’s a group of vertebrate paleontologists that want to ask questions that only Antarctic fossils can answer,” Clarke said.

It will be Clarke’s first trip to the Antarctic, though her fieldwork has often taken her to the Southern Hemisphere and locations from Argentina to Peru to New Zealand. Her work in South America, in particular, has shed new light on penguin evolution. [See related article: Penguins of a feather.]

But it’s in Antarctica where she believes more evidence is waiting to be found to show that the ancestors of modern birds lived more than 65 million years ago. Most scientists believe an asteroid hit the Earth and caused a cataclysmic extinction. Non-avian dinosaurs disappeared, along with an estimated three-quarters of all species.

“For parts of and close relatives of the crown clade — relatives of living bird lineages — Antarctica is the place to go. And Vega, specifically, is the place to go — globally,” Clarke said.

Vega Island, a small island off the Antarctic Peninsula, has proven to be relatively rich with fossils from the Late Cretaceous, about 80 million to 65 million years ago. The asteroid impact, which marks the so-called K-T Boundary, is estimated to have occurred around 64 million years ago.

It was on Vega where the Argentine scientists found the specimen that Clarke and colleagues would later call Vegavis iaai, which falls within the order Anseriformes, which includes ducks, geese and swans.

Photo Courtesy: Julia Clarke

Vegavis iaai concretion, left, and the CT scan of the rock and bird fossils.

The rock specimen from Vega contained avian vertebrae and pelvic bones among other bits of skeleton. Clarke used a high-resolution X-ray CT scanner to see the fossils without breaking the rock and possibly damaging the material.
In spite of the Vega evidence, there is still contention among paleontologists of what lineages are present in the Cretaceous prior to the K-T boundary, according to Clarke.

In 2008, she and co-principal investigator Judd Case at Eastern Washington University received a Small Grant for Exploratory Research (SGER) from the National Science Foundation (NSF) to pull together data and experts on Antarctic fossils from the last 20 years to see if more evidence existed to support the theory of a robust modern radiation from Antarctica.

It’s a good start, Clarke said, but added, “What we really need are new specimens because some of the important material that Case and the Argentine teams collected during their field seasons can just hint at the bird species present.

“It is just the tantalizing beginning of what we need to know; we need to get better specimens. … There’s arguably no better material in the world than what’s come out of Vega so far. There’s a lot more work that can be done there.”

Hence the expedition to the islands of the Antarctic Peninsula, which requires a trip aboard a research vessel toward the end of the Southern Hemisphere summer in February. The scientists will make day trips to the islands from small inflatable boats, as well as work out of field camps on the islands for days at a time.
The researchers can expect long hours in cold conditions, sifting through rocks and dirt for the small fragments that might offer further clues about the ancient history of birds, mammals and dinosaurs.

For her part, Clarke is hesitant to state that Antarctica was ground zero for modern bird evolution — but she also doesn’t dismiss the possibility. “If we can increase our sampling globally, we can get a better sense of what role Antarctica played in the diversification of birds. We don’t know that it’s the area of origin,” she said.

“Finding bird fossils is always a rare occurrence, but based on what we specimens have been collected from Antarctica to date, work in this region has a high probability of success. In terms of spinning a roulette wheel of fossil discovery, if you will, I think it’s weighted in our favor in this case. I think we’re going to find more complete material if we can spend the time at the sites.”

NSF-funded research in this story: Julia Clarke, University of Texas at Austin, Award Nos. 0927341, 0408308, 0731404 (with Judd Case, Eastern Washington University).

Source

Drag reduction by air release promotes fast ascent in jumping Emperor Penguins—a novel hypothesis

2011-01-22T19:14:00.000-08:00

MEPS prepress abstract - doi: 10.3354/meps08868

Drag reduction by air release promotes fast ascent in jumping Emperor Penguins—a novel hypothesis

John Davenport*, Roger N. Hughes, Marc Shorten, Poul S. Larsen

*Email: j.davenport@ucc.ie

ABSTRACT: To jump out of water onto sea ice, emperor penguins must achieve sufficient underwater speed to overcome the influence of gravity when they leave the water. The relevant combination of density and kinematic viscosity of air is much lower than for water. Injection of air into boundary layers (‘air lubrication’) has been used by engineers to speed movement of vehicles (ships, torpedoes) through sea water. Analysis of published and unpublished underwater film leads us to present a hypothesis that free-ranging emperor penguins employ air lubrication in achieving high, probably maximal, underwater speeds (mean 5.3 m s^-1, SD 1.01 m s^-1), prior to jumps. Here we show evidence that penguins dive to 15-20 m with air in their plumage and that this compressed air is released as the birds subsequently ascend whilst maintaining depressed feathers. Fine bubbles emerge continuously from the entire plumage, forming a smooth layer over the body and generating bubbly wakes behind the penguins. In several hours of film of hundreds of penguins, none were seen to swim rapidly upwards without bubbly wakes. Penguins descend and swim horizontally at about 2 m s^-1; from simple physical models and calculations presented, we hypothesise that a significant proportion of the enhanced ascent speed is due to air lubrication reducing frictional and form drag, that buoyancy forces alone cannot explain the observed speeds, and that cavitation plays no part in bubble formation.

Source

How Seabirds Share Their Habitat

2011-01-17T07:15:00.000-08:00

Gentoo penguins in a colony: The bird in the middle watches over two chicks and carries a GPS-depth logger which was fixed to the plumage. The tape shows distinct signs of the animal’s most recent dive when the penguin was hunting in more than 100 metres depth. (Credit: Petra Quillfeldt)

How Seabirds Share Their Habitat

ScienceDaily (Jan. 13, 2011) — When different species of seabirds share a habitat with limited sources of food, they must differ in their feeding habits. This specialisation is known by biologists as an "ecological niche." Researchers at the Max Planck Institute for Ornithology in Radolfzell have investigated how flexible these ecological niches really are. They discovered that the preying habits of diving seabirds are very different, both in location and timing, within species as well as between different species.

Ecological niches are not inflexible; they are affected by different habitats and the need to avoid competition with neighbours or evade predators, and also lead to different forms of behaviour within a single species.
Seabirds are an excellent species for studying the question of how animals share the limited supply of food in their habitat. Seabirds must live on land during the breeding season, and over this period they have to share space and food with many other animals. The birds breed in nesting colonies, often in confined spaces that provide protection from predators -- the food supply, however, is widely distributed throughout the sea off the coast. The birds must leave the colony to find food and then return to the islands to feed their chicks.

The scientists wanted to know how several species, similar in their demands, are able to breed together on an island and what exactly the differences in their ecological niches are. Using GPS-depth loggers that allow scientists to track birds detailed in three dimensions, researchers in the past have discovered the hunting areas and depths of several diving seabirds, such as penguins and cormorants, but always only for sample colonies. Until now it has been unknown whether these data can be transferred to entire species.

On New Island, part of the Faulkland Islands in the southern Atlantic Ocean, scientists at the Max Planck Institute for Ornithology used GPS-depth loggers to comprehensively study complete a comprehensive study of the hunting habits of four diving seabirds: three species of penguins -- Gentoo penguins, Rock Hopper penguins and Magellan penguins -- and Imperial shags. In addition, the researchers compared two colonies of each of the three penguin species.

"The results were very surprising," says biologist Dr. Juan Masello. "Based on the ecological niche theory, we had expected especially strong differences between species. However, the data show that the spatial and temporal distribution of birds within the species can also differ greatly."

Magellan penguins, for example, used hunting areas about 40 kilometres apart from each other, whereas the two colonies on land were only two kilometres apart. In contrast, one of the Gentoo penguin colonies often hunted at night, while the other neighboured colony hunted only in the daytime. In this way, the colonies avoid an overlap in feeding areas and small-scale differences are used effectively." adds Dr. Petra Quillfeldt. In the colony of Imperial shags, the females and males hunt both at different times and places: in the mornings, the females go hunting near the coast, and in the afternoons, the males hunt in the open sea. Thus the different species of seabirds found different solutions to avoid competing with their own species for food.

"Of course, food is not the only factor that determines the distribution of birds around the island," Dr. Quillfeldt explains. "In two of the penguin species, it was very clear that the animals avoided swimming near a seal colony where they could themselves become the prey. This dangerous zone also contributed to the spatial separation of the birds in the sea."

This is the first comprehensive study showing the ecological niches within a species, as well as between species, over the same period of time. It shows that seabirds of different species, as well as colonies of the same species, differ in their temporal and spatial distribution and that they search for food in different areas of the ocean, often far apart, and at different depths and temperatures. The ecological niches of the species studied are far less rigid than previously thought. Even small differences in habitat or in behaviour, or the need to avoid competition or predators, contribute to this specialisation.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Max Planck Institute for Ornithology, via AlphaGalileo.

Journal Reference:

Masello, J.F., Mundry, R., Poisbleau, M., Demongin, L., Voigt, C., Wikelski, M. & Quillfeldt P. Diving seabirds share foraging space and time within and among species.. Ecosphere, December 20, 2010 DOI: 10.1890/ES/0-001031

Max Planck Institute for Ornithology. "How seabirds share their habitat." ScienceDaily 13 January 2011. 17 January 2011 <http://www.sciencedaily.com /releases/2011/01/110111132213.htm>.

That Controvery Over Flipper Bands

2011-01-17T07:11:00.000-08:00

King Penguins. Flipper-banded penguins have a 16% lower survival rate and produce 39% fewer chicks than non-banded birds. (Credit: iStockphoto/Benjamin Goode)

Flipper Bands Hinder King Penguins

ScienceDaily (Jan. 16, 2011) — A team of researchers headed by Yvon Le Maho, CNRS researcher at the Institut Pluridisciplinaire Hubert Curien (CNRS / Université de Strasbourg) and member of the Académie des Sciences, has demonstrated that, over a ten year period, flipper-banded penguins have a 16% lower survival rate and produce 39% fewer chicks than non-banded birds. These results were obtained through electronic monitoring of one hundred king penguins on Possession Island in the southern hemisphere. As a precautionary measure, French researchers have stopped banding penguins since the 1990s.

Supported (1) by the Institut Polaire Français Paul-Émile Victor, this work was carried out in collaboration with Oslo and Tromsø universities in Norway, the Tour du Valat biological station and the Muséum National d'Histoire Naturelle and has been published on 13 January in Nature, also featuring on the cover of the journal.

Penguins are excellent indicators of the state of health of marine ecosystems and thus make it possible to better understand the impact of climate change on biodiversity. As a matter of fact, these top predators of the Southern Ocean are at the summit of the marine food chain. Their population dynamics is thus conditioned by the evolution of marine resources; any modifications arising in their survival and breeding success reflect to a large extent the impact of climate on lower links in the food chain (fish, zooplankton, etc.). Until now, most of the available data has been obtained by banding the animals being monitored. However, unlike other birds, it is impossible for anatomical reasons to fit bands to penguins' feet. Researchers therefore fit them to their flippers. These metal bands can be read at a distance, thus avoiding any stress involved in recapturing the penguins. The use of such flipper bands however raises serious questions as they can have deleterious effects on the animal. These effects include injuring flipper tissues or increasing energy expenditure while swimming or fishing due to the hydrodynamic drag effect on the flippers that the penguins use to propel themselves. Short-term studies (maximum one year) have concluded that banding has no impact. As a precaution, certain researchers, including French teams, have abandoned it but it is still used throughout the world. In addition, some scientists continue to rely on data from banded birds.

For the first time, a French-Norwegian team has conducted a long-term study, the objective of which was to monitor, over a ten year period, one hundred king penguins with electronic tags implanted under their skin, half of which were also fitted with a flipper band. The penguins were identified individually by radiofrequency using antennas buried along their passageways, between the colony and the sea. This electronic monitoring system was developed in 1998 by Le Maho's team at the Institut Pluridisciplinaire Hubert Curien (CNRS / Université de Strasbourg). The researchers focused on two key parameters for monitoring the evolution of this penguin population: their mortality rate and their breeding success. Their results unequivocally prove the significant impact of flipper banding, which affects both the survival and breeding of these animals, in the medium and long term. The banded population's growth rate is a fortiori also affected. In fact, over the last decade, the 50 banded penguins produced 39% fewer chicks (from laying until the chicks can feed for themselves). In addition, their mortality was 16% higher than that of non-banded birds.

The banded birds arrive later at their reproduction sites and, after having been banded for 10 years, they continue to have a delayed breeding cycle on account of their longer foraging trips. This study thus refutes the theory that penguins get used to such bands after a certain time. Another very important result is that banded penguins do not react in the same manner as non-banded penguins to climatic variability (mainly sea temperature). This is why, depending on the year and the environmental conditions, the effect of banding is more or less perceptible. "In favorable periods, when the sea temperature is low and food resources are abundant, there is virtually no difference between banded and non-banded animals," explains Claire Saraux, the leading author of this article. "On the other hand, when the sea temperature is higher, the penguins need to forage further to find their food and banded birds then stay longer at sea." These results thus demonstrate the need for long-term studies to test the possible effects of methods used to monitor animal populations.

From an ethical point of view, this study calls into question the numerous banding campaigns that are still ongoing. These results are obviously specific to penguins and cannot be generalized to foot-banded flying birds. Furthermore, since banded and non-banded penguins do not react in the same way to changes in sea temperature, this study demonstrates that flipper banding introduces an important bias in the study of climatic effect on the dynamics of penguin populations. Since current knowledge of this effect is based to a large extent on data from banded birds, such information must therefore be considered with caution.

(1) This work benefited from the financial and/or logistical support of CNRS, IPEV, TAAFs, the Fondation Bettencourt-Schueller and the Fondation des Treilles.
Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by CNRS (Délégation Paris Michel-Ange), via AlphaGalileo.

Journal Reference:

Claire Saraux, Céline Le Bohec, Joël M. Durant, Vincent A. Viblanc, Michel Gauthier-Clerc, David Beaune, Young-Hyang Park, Nigel G. Yoccoz, Nils C. Stenseth, Yvon Le Maho. Reliability of flipper-banded penguins as indicators of climate change. Nature, 2011; 469 (7329): 203 DOI: 10.1038/nature09630

CNRS (Délégation Paris Michel-Ange). "Flipper bands hinder king penguins." ScienceDaily 16 January 2011. 17 January 2011 <http://www.sciencedaily.com /releases/2011/01/110114155243.htm>.

Future Climate for Penguins Discussed

2011-01-17T07:05:00.000-08:00

A pair of chinstrap penguins in Antarctica. New research suggests that, if carbon dioxide emissions continue on their current trajectory, Earth may return to a climate of tens of millions of years ago when the Antarctic ice sheet did not exist. (Credit: © UCAR, Photo by Andrew Watt)

Earth's Hot Past Could Be Prologue to Future Climate

ScienceDaily (Jan. 14, 2011) — The magnitude of climate change during Earth's deep past suggests that future temperatures may eventually rise far more than projected if society continues its pace of emitting greenhouse gases, a new analysis concludes.

The study, by National Center for Atmospheric Research (NCAR) scientist Jeffrey Kiehl, will appear as a "Perspectives" piece in this week's issue of the journal Science.
Building on recent research, the study examines the relationship between global temperatures and high levels of carbon dioxide in the atmosphere tens of millions of years ago. It warns that, if carbon dioxide emissions continue at their current rate through the end of this century, atmospheric concentrations of the greenhouse gas will reach levels that existed about 30 million to 100 million years ago, when global temperatures averaged about 29 degrees Fahrenheit (16 degrees Celsius) above pre-industrial levels.
Kiehl said that global temperatures may gradually rise over centuries or millennia in response to the carbon dioxide. The elevated levels of carbon dioxide may remain in the atmosphere for tens of thousands of years, according to recent computer model studies of geochemical processes that the study cites.
The study also indicates that the planet's climate system, over long periods of times, may be at least twice as sensitive to carbon dioxide than currently projected by computer models, which have generally focused on shorter-term warming trends. This is largely because even sophisticated computer models have not yet been able to incorporate critical processes, such as the loss of ice sheets, that take place over centuries or millennia and amplify the initial warming effects of carbon dioxide.
"If we don't start seriously working toward a reduction of carbon emissions, we are putting our planet on a trajectory that the human species has never experienced," says Kiehl, a climate scientist who specializes in studying global climate in Earth's geologic past. "We will have committed human civilization to living in a different world for multiple generations."
The Perspectives article pulls together several recent studies that look at various aspects of the climate system, while adding a mathematical approach by Kiehl to estimate average global temperatures in the distant past. Its analysis of the climate system's response to elevated levels of carbon dioxide is supported by previous studies that Kiehl cites. The work was funded by the National Science Foundation, NCAR's sponsor.

Learning from Earth's past

Kiehl focused on a fundamental question: when was the last time Earth's atmosphere contained as much carbon dioxide as it may by the end of this century?
If society continues on its current pace of increasing the burning of fossil fuels, atmospheric levels of carbon dioxide are expected to reach about 900 to 1,000 parts per million by the end of this century. That compares with current levels of about 390 parts per million, and pre-industrial levels of about 280 parts per million.
Since carbon dioxide is a greenhouse gas that traps heat in Earth's atmosphere, it is critical for regulating Earth's climate. Without carbon dioxide, the planet would freeze over. But as atmospheric levels of the gas rise, which has happened at times in the geologic past, global temperatures increase dramatically and additional greenhouse gases, such as water vapor and methane, enter the atmosphere through processes related to evaporation and thawing. This leads to further heating.
Kiehl drew on recently published research that, by analyzing molecular structures in fossilized organic materials, showed that carbon dioxide levels likely reached 900 to 1,000 parts per million about 35 million years ago.
At that time, temperatures worldwide were substantially warmer than at present, especially in polar regions -- even though the Sun's energy output was slightly weaker. The high levels of carbon dioxide in the ancient atmosphere kept the tropics at about 9-18 degrees F (5-10 degrees C) above present-day temperatures. The polar regions were some 27-36 degrees F (15-20 degrees C) above present-day temperatures.
Kiehl applied mathematical formulas to calculate that Earth's average annual temperature 30 to 40 million years ago was about 88 degrees F (31 degrees C) -- substantially higher than the pre-industrial average temperature of about 59 degrees F (15 degrees C).

Twice the heat?

The study also found that carbon dioxide may have at least twice the effect on global temperatures than currently projected by computer models of global climate.
The world's leading computer models generally project that a doubling of carbon dioxide in the atmosphere would have a heating impact in the range of 0.5 to 1.0 degree C watts per square meter. (The unit is a measure of the sensitivity of Earth's climate to changes in greenhouse gases.) However, the published data show that the comparable impact of carbon dioxide 35 million years ago amounted to about 2 degrees C watts per square meter.
Computer models successfully capture the short-term effects of increasing carbon dioxide in the atmosphere. But the record from Earth's geologic past also encompasses longer-term effects, which accounts for the discrepency in findings. The eventual melting of ice sheets, for example, leads to additional heating because exposed dark surfaces of land or water absorb more heat than ice sheets.
"This analysis shows that on longer time scales our planet may be much more sensitive to greenhouse gases than we thought," Kiehl says.
Climate scientists are currently adding more sophisticated depictions of ice sheets and other factors to computer models. As these improvements come on line, Kiehl believes that the computer models and the paleoclimate record will be in closer agreement, showing that the impacts of carbon dioxide on climate over time will likely be far more substantial than recent research has indicated.
Because carbon dioxide is being pumped into the atmosphere at a rate that has never been experienced, Kiehl could not estimate how long it would take for the planet to fully heat up. However, a rapid warm-up would make it especially difficult for societies and ecosystems to adapt, he says.
If emissions continue on their current trajectory, "the human species and global ecosystems will be placed in a climate state never before experienced in human history," the paper states.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by National Center for Atmospheric Research/University Corporation for Atmospheric Research.

Journal Reference:

Jeffrey Kiehl. Lessons from Earth's Past. Science, 2011; 331 (6014): 158-159 DOI: 10.1126/science.1199380

National Center for Atmospheric Research/University Corporation for Atmospheric Research. "Earth's hot past could be prologue to future climate." ScienceDaily 14 January 2011. 17 January 2011 <http://www.sciencedaily.com /releases/2011/01/110113141607.htm>.

Fossil Hunt in Antarctica

2011-01-17T07:03:00.000-08:00

Photo Credit: Patrick O'Connor

Paleontologists led by Ross MacPhee look for fossils on Snow Island in the South Shetland Islands off the Antarctic Peninsula. MacPhee is particularly interested in marsupial fossils that could fill out the picture of their dispersal through the Southern Hemisphere.

Reverse course

Paleontologists seek evidence that marsupials arose in Antarctica

By Peter Rejcek, Antarctic Sun Editor

Posted January 14, 2011

Ever see the logo for the Sherwin-Williams Company? It shows a bucket of paint tipped over above the planet. The paint covers the Northern Hemisphere, oozing and dripping south.
Ross MacPhee thinks it’s a perfect metaphor for the disrespect the Southern Hemisphere receives from some of his colleagues regarding the evolution and distribution of mammals tens of millions of years ago when Antarctica was part of a larger continent called Gondwana.
This austral summer he’ll make a fourth attempt to find mammalian fossils that at least prove some kinds of these land animals were present on the continent long before Antarctica finally separated from other land masses and started to go into a deep freeze 40 million years ago.
Before then, Antarctica was sandwiched between South America and Australia, all remnants of the former supercontinent Gondwana. MacPhee is particularly interested in the history of Australian marsupials, believing that their ancestors emerged in South America and traveled across Antarctica to Australia sometime in the neighborhood of 80 million years ago.
“It was relatively easy, not only for the small guys like the marsupials, but also bigger ones like some of the southern ungulates [hoofed animals] to get across the land bridge connecting Antarctica and South America and settle down until Antarctic winter came in permanently about 40 million years ago,” MacPhee said during an interview at the American Museum of Natural History, where he is a curator in the mammalogy department.

Photo Credit: Patrick O'Connor

Fossilized wood found on James Ross Island.

The problem is that fossil record from Antarctica is spotty at best, especially considering most of the continent is entombed in ice. “That leaves you with a few little windows of seasonally bare ground on the Antarctic Peninsula and nearby islands,” MacPhee noted.
One of the better windows is on Seymour Island off the tip of the Antarctic Peninsula. Almost 30 years ago, U.S. scientists in the journal Science described the first fossil land mammal found in Antarctica, belonging to the extinct marsupial family Polydolopidae. The fossils were recovered from rocks about 45 million years old.
The find strengthened the theory that Australian marsupials originated from South American species that dispersed across Antarctica prior to about 65 million years ago, MacPhee said. Marsupials are mammals that are distinguished by the pouches many of them use to carry their young — the most well-known examples being kangaroos.
More recently, a study published last summer in the online journal PLoS Biology uses DNA data to suggest that Australian marsupials evolved from a common South American ancestor well before the end of the Cretaceous period 65 million years ago when the dinosaurs famously met their end.

Photo Credit: AMNH

Ross MacPhee

MacPhee, “wildly” but enthusiastically speculating on what he might find during his upcoming expedition, said the possible discovery of marsupial fossils on Seymour or neighboring islands as primitive as those in South America could indicate that the divergence (or origin) of Australian marsupials actually began in Antarctica rather than South America proper.
“It would be damn interesting. It implies that Antarctica has been more than a superhighway for species to occasionally traverse,” he said. “It means that during times like the late Cretaceous, when it was much warmer than today, important episodes in mammal evolution might have happened there.”
Antarctica of 80 million years ago would hardly resemble the frozen wasteland of today. Some regions would have sported highly diverse vegetation, based on paleobotanical evidence. That means a temperate climate, which favors mammals.
“Since there was a great variety of plants, that implies there would have been a commensurately great variety of arthropods and insects, which means there would have been all kinds of available niches for mammals — small mammals, in particular — that eat insects,” MacPhee said.

Julia Clarke, as associate professor in the Department of Geological Sciences at the University of Texas at Austin, led a team five years ago that reported that close relatives of at least one order of modern birds co-existed with dinosaurs.
The new species, Vegavis iaai, was collected in 1992 by scientists from Argentina on Vega Island off the Antarctic Peninsula. Clarke and her U.S. and Argentine team re-examined the material more than a decade later.
It offered some of the best fossil evidence to date that linked modern bird divergence, the spread of today’s species, before the K-T boundary — when geologic time turned the page from the Cretaceous to the Tertiary period after the mass extinction of the dinosaurs.
MacPhee said such evidence about the Vega waterfowl helps turn the Sherwin-Williams model upside down. “It does suggest the southern end of the world is not as biogeographically irrelevant as it’s been previously — inadvertently perhaps — thought to be.”

Photo Credit: Wikipedia Commons

Map of the South Shetland Islands.

Clarke will join MacPhee and several other paleontologists, including dinosaur fossil experts, on this latest expedition to the islands near the Antarctic Peninsula in February 2011.
“I’m really excited to have the opportunity after looking at all of the Antarctic material to go down there,” Clarke said. “I’ve never been to Antarctica, and I’m very excited to see what we’ll find.”
MacPhee hopes the fourth time is the charm. His first try in 2007 was largely frustrated by heavy snow on the ground that made finding the small fossils he would expect to find nearly impossible. The ancient marsupials would be about the size of modern shrews, up to 100 grams in weight — something that could easily fit in the palm of your hand. [See previous article: Bridge to the past.]
A freak storm in 2008 wrecked the team’s field camp, forcing an early end to their season. Last year, sea ice conditions prevented the research vessel carrying the scientists to access the islands except for two days. [See previous article: A big blow.]
Despite the setbacks, MacPhee is willing to commit another two months to his search for mammalian fossils.

Photo Credit: N. Adam Smith

Julia Clarke

“I feel it’s important. People have to be willing to put up with some pain and suffering if they have any expectations of being successful,” he said philosophically. “Antarctica is not going to be kind. We already know that with regard to how hard it has been to collect mammalian or indeed any vertebrate fossils.”
The team hopes to begin its search on Vega Island, where Clarke’s avian fossils were found.
Other likely expedition sites include nearby Seymour and James Ross islands, where others have found fossils from younger geological periods. In fact, Argentinean scientists recently uncovered ancient turtle fossils on Seymour Island dating from roughly 45 million years ago that don’t belong to any species known to live in the region during that time period.
The scientists expect to spend long hours on their hands and knees, crawling along the ground hoping to spy interesting-looking bits.
“I’m somewhat sanguine, although you have to recognize the realities. That next rock that you needed to kick over to find that tooth that was going to explain all of this might be the very rock that you ignore,” he said.
“For my purposes it’s worth doing, because I think the Antarctic part of mammalian divergence and diversification story in the latter part of the Cretaceous is the part that we know least about. Virtually any evidence would suggest new possibilities.”

Source

Indian, Australian joint team studying penguin evolution

2011-01-08T12:02:00.000-08:00

Sydney, Jan 7 (IANS) A joint team of Indian and Australian scientists is studying molecular changes in Adelie, a penguin species commonly found along the entire Antarctic coast, triggered by global warming.
The experts are also looking at the larger issue of whether climate change drives evolution.

Australian team leader David Lambert is collaborating with Siva Swaminathan, who leads the Indian side, under the aegis of the Australia-India Strategic Research Fund (AISRF).

The AISRF was established in 2006 to facilitate and support science and technology research cooperation between the two countries.

'When global temperatures change (up or down), many animals do not biologically adapt to that change, but simply move to where things are warmer or cooler,' Lambert said.

'With global warming, Adelie penguins are not able to move to a cooler place since they already live in the coldest place on earth. So, they have no option but to adapt,' he said.

In yet another collaborative programme, Arnold Dekker from the Commonwealth Scientific and Industrial Research Organisation (CSIRO) led an Australian team at a recent workshop with Indian researchers to monitor ocean health through remote sensing.

Dekker said researchers use satellite-based observation of earth's coasts and oceans to monitor ocean colour, which arises from changes in algae, suspended and dissolved organic material.

'Ocean colour helps us understand the interactions between aquatic ecosystems, climatic factors and human impacts,' he said.

The experts at the workshop agreed that understanding these interactions can help in forming better policies for protecting coastal reefs and ecosystems from potentially harmful disturbances caused by human activity and environmental stresses.

Source

Happy New Year!

2011-01-01T06:57:00.000-08:00

Penguin Evolution Revisited

2010-12-25T20:43:00.000-08:00

By John Gibb on Sun, 26 Dec 2010

News: Dunedin

Click photo to enlarge

University of Otago geologist Assoc Prof Ewan Fordyce examines a fossilised penguin wing bone that shows signs of a grooves heat-retention mechanism. Photo by Jane Dawber.

Most people think of penguins as cold-water or polar birds, but latest research linked to the University of Otago sheds new light on that traditional view. A research paper published last week in British-based journal Biology Letters also offers new insights into the evolutionary development of penguins.
The paper's first author is Dr Daniel Thomas, a New Zealander who is a postdoctoral fellow at the University of Cape Town, South Africa.
His recent Otago doctorate was supervised by Associate Prof Ewan Fordyce, who heads the Otago University geology department.
Prof Fordyce, who also contributed to the paper, said it had long been believed that penguins thrived by adapting to increasingly cold conditions, including in the now largely ice-covered Antarctic.
This region, which had earlier been semi-tropical, became glaciated about 34 million years ago.
However, the paper points out that, much earlier, about 49 million years ago, penguins lived in much warmer conditions, when some ocean surface temperatures were about 25degC.
And it was at that stage that penguins evolved a key heat-retention mechanism that effectively pre-adapted them to thrive in later, much colder, conditions, including in the Antarctic.
It seemed ''counterintuitive'' for such mechanisms to evolve at a time of global warmth, but researchers suspected that the evolutionary change occurred then ''to allow penguins to forage for food in cool depths, far below the warm surface waters'', Prof Fordyce said.
Faced with a ''constant threat from hypothermia'' in deep, cold waters, penguins had developed a ''counter-current heat exchanger'', which managed the flow of blood along the wing and significantly improved heat retention and energy efficiency.
Wings were used to help propel the birds through the water.
Prof Fordyce said grooves in fossilised wing bones showed evidence of this mechanism.
By the mechanism, warmer blood that was being moved out to the wings was also used to heat the cooler blood coming back from the wings before it re-entered the penguin body core.
Dr Thomas was a ''very, very good researcher'' and the study highlighted the ''power of fossils'' to show how animals had evolved, Prof Fordyce said.
- john.gibb@odt.co.nz

Source

Penguins Weren't Always Adapted to the Cold

2010-12-25T19:50:00.000-08:00

Palaeeudyptes, one of the "giant" penguins lived during the Oligocene, about 28 million years ago. Bones in this bird and its relatives show clear evidence of a heat-conserving structure known as a humeral arterial plexus. Credit: the Geology Museum, University of Otago, Dunedin, New Zealand.

How Penguins Got Their Cold-Weather Coats

By Charles Q. Choi, LiveScience Contributor
posted: 21 December 2010

Those tuxedo-wearing birds that inhabit Earth's coldest continent may have evolved a means of retaining heat when they were still living in warm climates, scientists now suggest.

A key adaptation that helped modern penguins to invade the cold waters of Antarctica within the last 16 million years is the so-called humeral arterial plexus, a network of blood vessels that limits heat loss through the wings.

The plexus routes blood coming into the body from the wings past the blood traveling from the body to the wings. As such, the cooler blood from the wings, which get cold in the water, is heated up by warmer blood from the body, thus conserving heat.

To find out more about how this anatomical structure evolved, scientists investigated seven live penguin species and 19 fossil ones. In live specimens, they found the plexus leaves behind grooves in the upper arm bone called the humerus. As such, they could see when this structure began appearing in extinct penguin species from the fossil record.

Surprisingly, they found the plexus arose at least 49 million years ago, when the planet was going through a warm "greenhouse Earth" phase due to vast amounts of global warming gases that got pumped into the atmosphere, perhaps by volcanism.

"I began this work thinking we would relate heat retention in penguins to the global cooling that took place at the Eocene-Oligocene boundary [about 34 million years ago], whereas in fact, penguins were cold-water-tolerant millions of years earlier," researcher Daniel Thomas, a paleontologist at the University of Cape Town in South Africa, told LiveScience.

The earliest known penguins to feature the plexus lived on the lost continent of Gondwana, on what is now Seymour Island in Antarctica. Back then, the waters there were 59 degrees Fahrenheit (15 degrees Celsius), compared with the water's current average temperature of 34 degrees F (1 degree C). (Scientists can deduce ancient temperatures by looking at the chemistry of fossils — for instance, magnesium levels in the shells of certain organisms rise as temperatures go up.)

The researchers suspect the plexus first evolved to help penguins save energy during long foraging trips in the cold water, as the structure evolved in concert with dramatic skeletal changes that promoted buoyancy and reduced drag, thus improving deep-diving and long-distance swimming. As global climate cooled, the plexus then found a new use, proving key to the penguins' invasion of Antarctic ice sheets.

"Penguins have occupied much of the Southern Hemisphere in the last 40 million years because of their tolerance for cold water," Thomas said.

Thomas and his colleagues Dan Ksepka and Ewan Fordyce detailed their findings online Dec. 22 in the journal Biology Letters.

(Below)
The pink underside of the yellow-eyed penguin's wings shows how its heat-regulating humeral arterial plexus looks from the outside. Credit: Daniel Thomas.

Source

Busy Adeliés

2010-12-15T12:06:00.000-08:00

Penguin Update from Dr. Dee Boersma

2010-12-15T11:59:00.001-08:00

Hello Penguin Lovers and Supporters --

Here's a penguin update. Chicks have hatched!! We know that the Punta Tombo colony covers 400 hectares and the update tells you how many active nests we estimate from survey data in 1987 and 2006. Read to see what you helped us accomplish. Thanks for your interest in the penguins of patagonia and Happy Holidays.

P. Dee Boersma, Ph.D

Wadsworth Endowed Chair in Conservation Science

Department of Biology, Box 351800

University of Washington

Seattle, WA 98195-1800

Phone: 206-616-2185

Fax: 206-221-7839

boersma@u.washington.edu

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Penguin_update mailing list
Penguin_update@u.washington.edu
http://mailman2.u.washington.edu/mailman/listinfo/penguin_update

update_Dec_2010.pdf
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