Wednesday, July 30, 2014

Emperor penguins on the decline?

Modeling the future of a charismatic bird

July 30, 2014 | Emperor penguins, the large, charismatic birds known from their frequent film and TV appearances, are in danger. A collaborative research project is drawing attention to the impending plight of the emperors. By 2100, according to a new study, their numbers will have fallen by around 19% and will continue to decline, qualifying the species for endangered status.

Emperor penguin communities entirely ring the continent of Antarctica. Of the 45 known colonies, only one has been extensively studied for decades, and most of the others have never been visited by humans, nor are they likely to be. Emperors live on sea ice off the coast of the continent, and the amount of ice plays a major role in determining the health of a colony. Too much ice and the penguins have a long, debilitating walk to the sea and food; too little ice and the colony is more exposed and vulnerable to predation.
Penguins and climate change: Emperor penguins at Snow Hill Island, Antarctica, 2009
A colony of emperor penguins at Australia's Snow Hill Island, October 2009. (Photo by Jenny Varley, Wikimedia Commons.)
Stéphanie Jenouvrier (Woods Hole Oceanographic Institution) is an expert on penguin life, and she wanted to project the size of emperor populations into the future as Earth’s climate warms. The problem, she says, was her “limited background on climate science.” Meanwhile, at NCAR, senior scientist Marika Holland is a climate scientist with a longstanding specialty in modeling sea ice changes, although she has never been to Antarctica and has never seen an emperor penguin.

Aware of Holland’s previous work, Jenouvrier contacted her and Julienne Stroeve at the University of Colorado’s Cooperative Institute for Research in Environmental Sciences. The three of them collaborated on preliminary studies published in 2009. Jenouvrier received a fellowship from CIRES and worked in Boulder for almost a year, collaborating closely with Holland, Stroeve, Mark Serreze at the CIRES National Snow and Ice Data Center, and other scientists on a follow-up study, published in 2012, and on their most extensive update, recently published in Nature Climate Change.

The biologists used long-term data from the one well-studied emperor colony, off the coast of Terre Adélie, to estimate the relationship between sea ice and rates of breeding success and survival of chicks. They used the record of penguin population and sea ice concentrations at Terre Adélie to estimate vital rates (births/deaths) and population dynamics at each colony.

Learning each other’s languages: biology and climate

The next challenge was to project sea ice changes over the rest of the 21st century and relate that to the health of each penguin community. Sea ice off Antarctica does not behave uniformly: although the total area of sea ice around the continent has increased somewhat in recent years, the trends vary by region during the course of a year and over longer periods. Sea ice must therefore be studied in the relatively small segments that host individual colonies, in order to assess the viability of penguin populations. At first, says Holland, the biologists and climate modelers spoke two different languages, which was “a bit of a barrier.” The frequent interchanges during Jenouvrier’s year in Boulder helped bridge that gap, she adds.

The sea ice scientists began with a group of 20 or so climate models and settled on a widely used midrange scenario of emissions produced for the Intergovernmental Panel on Climate Change called SRES A1B. Once the penguin population models and sea ice change models were set, climate projections were fed into the penguin population models. Due to inherent uncertainties in the models, Jenouvrier ran tens of thousands of computer simulations to achieve the results that the team published.

They found that sea ice will generally decline and its variability will increase by the end of this century. As a result, the simulations indicate that emperor populations will increase by around 10% through midcentury, but then decline to 19% below current levels by 2100. One group of 7 colonies facing the Ross Sea will still be non-threatened by that time, although with a reduced population. On the other side of the continent, facing the Indian Ocean and Weddell Sea, 10 colonies will face quasi-extinction. Most of the rest will qualify as endangered.

The collaborative nature of a study like this, Holland says, allows the expertise of NCAR scientists to inform such other fields as biology and economics to better understand the global system. The researchers conclude that the emperor penguin is “fully deserving of Endangered status due to climate change, and can act as an iconic example of a new global conservation paradigm for species threatened by future climate change.”
WriterHarvey Leifert

ContactDavid Hosansky, NCAR & UCAR Communications
Collaborating institutionsNational Center for Atmospheric Research
University of Amsterdam
University College London
University of Colorado/Cooperative Institute for Research in Environmental Sciences
University of La Rochelle
Woods Hole Oceanographic Institution
FundersAlexander von Humboldt Foundation
European Research Council
Grayce B. Kerr Fund
National Oceanic and Atmospheric Administration
National Science Foundation
Penzance Endowed Fund in Support of Assistant Scientists
Woods Hole Oceanographic Institution

Dive deeper

Stéphanie Jenouvrier, Marika Holland, Julienne Stroeve, Mark Serreze, Christophe Barbraud, Henri Weimerskirch and Hal Caswell, Projected continent-wide declines of the emperor penguin under climate change, Nature Climate Change (2014), doi:10.1038/nclimate2280

In Graphic Terms

Map of emperor penguin colonies
Annual mean change of sea ice concentrations (SIC) between the twentieth and twenty-first centuries and conservation status of emperor penguin colonies by 2100. SIC projections were obtained from a subset of atmosphere-ocean general circulation models. Dot numbers refer to each colony evaluated, with dot color showing conservation status (red = quasi-extinct, orange = endangered, yellow = vulnerable, green = not threatened).  (Figure 1 from Jenouvrier et al., Projected continent-wide declines of the emperor penguin under climate change, doi:10.1038/nclimate2280; image courtesy Nature Climate Change.)

Scientists Decode African Penguin Calls

An African penguin (Spheniscus demersus) calls out near Table Mountain National Park, Cape Town, South Africa. (Photo: © 167/Ralph Lee Hopkins/Ocean/Corbis)

Researchers are trying to figure out how "jackass" penguins—nicknamed for their braying vocalizations—communicate
There’s nothing quite like the sultry squawk of a jackass penguin. Coastal residents of Namibia and South Africa, African penguins (Spheniscus demersus) got the nickname “jackass” from their donkey-like calls.

But it turns out their vocalizations are a lot more complicated than haws and brays. A study published today in the journal PLoS ONE examines the vocal repertoire of African penguins. Researchers analyzed hours of audio and video and found that the quirky birds emit four different calls and that baby penguins emit two previously undescribed vocalizations. Perhaps most important, the researchers think they were able to discern what the penguins were trying to communicate with each call.

Understanding penguin call function has implications for conservation and learning about penguin biology. “Vocalizations have the opportunity to provide a huge amount of information about these birds,” says Livio Favaro, a biologist at the University of Turin and the lead author on the study. Encoded in penguin vocal calls are clues to their sex, age and social status.

Before this study, penguins were known to vocalize in four ways: contact calls (“Hey! I’m here. Where are you guys?”), agonistic or threat calls (“Watch it, buddy!”), and display songs directed towards mates, chicks and parents (“Heyyy”). Display songs fall into two categories, ecstatic and mutual, and are uttered alone or in pairs, respectively.

Most penguin vocal research has focused on species that don’t build nests, such as the Emperor and king penguin species in Antarctica, which rely on their vocal system to stick together. By contrast, aside from some basic descriptions and minimal audio, the vocalizations of African penguins—a species that does build nests—remain largely unknown. Previous work also limited the focus to the breeding season, rather than observing the birds over a longer time period.

Favaro and colleagues wanted to know if these nesting penguins voice different calls than their non-nesting cousins. They also sought to discern the accoustic intricacies of different types of calls. But studying penguin vocalizations in the wild can be difficult. Ambient noise, sounds from other animals and human interference can mess with the audio.

So for their study, Favaro and his colleagues selected a captive colony of 48 African penguins living at a zoo in Torino, Italy. For 104 separate days in 2010 and 2011 (both in and out of the breeding season), the researchers took audio and video of the penguins.

Using visualizations of the call notes called spectrograms, the researchers analyzed the acoustics of each call as well as the behavior of the penguin making the call. Based on patterns of behavior and acoustic similarities, four types of adult calls and two new calls unique to penguin chicks emerged from the noise. Statistical analysis of spectrograms confirmed that each call type represented a different vocalization.

You can see video footage of all six calls here:

Contact calls were single-syllable, averaging around half a second in length. When voicing them, penguins typically stood up with their beaks half open and extended their necks vertically as much as possible. When fighting, they extend their necks toward the other penguin and emitted agonistic calls, also one-syllable and sometimes followed by a peck.

Mutual display songs began with noise pulses, and when making them the penguins stretched out horizontally with wide-open beaks while emitting a lower pitched harmony. Finally, the penguins emitted an ecstatic display song, the longest and loudest of all vocalizations. The birds began with a series of short syllables as they thrust their chests upwards with wings spread and ended with one long note, occasionally two.

Both adults and juveniles displayed agonistic calls and contact calls, but penguin chicks emitted some additional calls of their own: begging moans and begging peeps. Begging moans were short, but typically emitted in sequence until fed. The chicks also bobbed their heads. Begging peeps were higher pitched and short, but could go on for several minutes until feeding.

Chicks began emitting begging peeps at three months of age. Moans, which sound more like adult calls, were more common in older chicks. So Favaro thinks that peeps and moans may represent the evolution of the same noise with age.

African penguin (Spheniscus demersus) with chicks, at the Boulders Colony, Cape Town, South Africa. Researchers found that penguin chicks emitted two unique sounds: begging moans and peeps. (Photo: © Herbert Kratky/imagebroker/Corbis)
Understanding penguin lingo could be used to develop audio systems that could provide a cheap and easy way of tracking and estimating populations. From a practical perspective, deciphering penguin audio could prove useful in penguin conservation. The International Union for the Conservation of Nature (IUCN) elevated African penguins to endangered status in 2010, and the birds currently face threats from habitat destruction to pollution and even egg collection.

Such threats put pressure on researchers to learn as much as they can about penguin vocalizations—and how they fit into the broader picture of the evolution of animal communication—before it’s too late.

Favaro and his colleagues next plan to delve into how penguins produce these complex calls through their syrinx, the bird equivalent of the larynx in humans, and how vocalizations identify an individual. In non-nesting species, birds use a two-voice system that creates a beat pattern unique to each individual, while other nesting species, such as the Adelie penguin, use pitch, frequency, and harmony to make unique calls from one penguin to another.

It’s even possible, the researchers suggest, that African penguin speech production follows a theory based on human vocalization that links individuality to variation in the vocal tract. If that proves to be the case, we may be more similar to penguins than we ever imagined.


Tuesday, July 29, 2014

Animals From Space: Polar Bears, Penguins Tracked Via Satellite

Satellite image showing penguin markings in the snow in Antarctica.
Brown smudges show an emperor penguin colony at Cape Colbeck, Antarctica, in a 2010 satellite image. Satellite photograph courtesy DigitalGlobe, Inc.
Jason Bittel

Published July 28, 2014

In the olden days of scientific research, the only way to know how many buffalo roamed the prairie or monkeys bounced around the rain forest was to trek out there and take a head count. But thanks to advances in satellite imagery, researchers today can take stock of some species without risking a single venomous snakebite or frost-bitten toe.

Take Seth Stapleton, a postdoctoral researcher at the University of Minnesota in St. Paul, who published a study this month in PLOS ONE on new ways to spot far-flung polar bears, including leveraging the same satellite that provides images for Google Earth. Even though polar bears are the biggest bear species alive today and one of the most widely studied large mammals on Earth, we know surprisingly little about their whereabouts across much of the remote Arctic.

To find the white bears on the icy landscape, Stapleton and colleagues restricted their scope to darker islands where bears often get stranded in the late summer after the surrounding ice melts. The researchers successfully identified nearly a hundred polar bears by satellite. In a separate test, they verified that what they were seeing were actually bears (and not rocks or foam) by conducting aerial surveys in a helicopter.

What's more, new advances in satellite resolution and automation may one day allow us to count polar bears no matter what they're standing on. "The technology is evolving so rapidly, it has the potential to open up huge areas of research and conservation avenues," said Stapleton.

Let's take a look at a few more animals getting the cosmic paparazzi treatment.

Photo of Emperor penguins in Antarctica.
Emperor penguins are seen in Dumont d'Urville in April 2012. Counting emperor penguins in Antarctica wasn't easy until researchers used new technology to map the birds from space.
Photograph by Stringer, Reuters/Corbis
Emperor Penguins

Emperors may be the largest penguins on Earth, but that isn't the only thing that makes them visible from space. In fact, the most conspicuous evidence of an emperor penguin colony is what they leave behind on the ice—their poop. "The brown stains stand out really well on the fresh snow," said Peter Fretwell, a scientist with the British Antarctic Survey. (Related: "Emperor Penguins Counted From Space—A First.") 

Using Landsat satellite images of Antarctica, Fretwell and his colleagues have found that they can use these "fecal stains" as an indicator of a potential colony. Once the team finds a brown spot, they can zero the satellites in to count birds individually or make population estimates based on how many penguins are huddled together.

Just by looking at such satellite images, Fretwell and his colleagues have more than doubled the number of known emperor penguin colonies.

Right Whales

Fretwell also led a study about detecting whales from space, published in PLOS ONE in 2013. Instead of scanning the whole ocean for whale tails, or flukes, his study focused on Golfo Nuevo, Argentina—a bay where right whales come to breed between July and November. Breeding areas are ideal for counting whales by satellite because many species choose calm, clear waters where they can bask near the surface with their calves. 

Fretwell found that it was indeed possible to manually count whales by satellite. What's more, he and his team looked at possible ways computer animation could help scientists cover more ground.
For instance, in the simplest analysis, the researchers found that the computer could identify all the bright areas of a whale-ish size and shape on a given image.

In fact, Fretwell said right whales may be easier for a computer to identify than other species, on account of the gray-white calluses that grow on the animal's dark heads. Just imagine having a growth on your face visible from space. 

Bats, Birds, and Turtles

If the goal is to spot an animal using satellite imagery, then the animal will obviously have to be relatively large. For instance, Stapleton said an adult male polar bear appears as no more than six to eight white pixels using the WorldView-2 satellite. But a new addition to the International Space Station, called ICARUS (International Cooperation for Animal Research Using Space), may one day soon help scientists keep tabs on individual animals smaller than a Smart car.

Most GPS tags log location data but lack the power to transmit that information up to a satellite. This means a study animal must be recaptured at some point to obtain that information—a particularly difficult feat when you're working with small migratory animals. But with the new ICARUS hardware, scientists will be able to employ more advanced GPS tags that transmit information back to the space station, which orbits much closer to Earth than most satellites do.

The ICARUS Initiative aims to track birds, bats, sea turtles, and rodents to better understand ecosystems, improve aviation safety, track endangered species, and monitor the spread of infectious diseases. And the transmitters are getting smaller all the time. One day soon, it may be possible to monitor a single monarch butterfly flying in your backyard from more than 200 miles (320 kilometers) up in the sky. 

Now that's out of this world.

Saturday, July 26, 2014

Siberian Discovery Suggests Almost All Dinosaurs Were Feathered

An illustration of Kulindadromeus zabaikalicus, a feathered dinosaur, in its natural environment.
This illustration of Kulindadromeus zabaikalicus, a newfound feathered dinosaur, shows it in its natural environment. Illustration by Andrey Atuchin

Dan Vergano
National Geographic
Published July 24, 2014

Almost all dinosaurs were probably covered in feathers, Siberian fossils of a tufted, two-legged running dinosaur dating from roughly 160 million years ago suggest.

Over the past two decades, discoveries in China have produced at least five species of feathered dinosaurs. But they all belonged to the theropod group of "raptor" dinosaurs, ancestors of modern birds. (Related: "Dinosaur-Era Fossil Shows Birds' Feathers Evolved Before Flight.")

Now in a discovery reported by an international team in the journal Science, the new dinosaur species, Kulindadromeus zabaikalicus (KOO-lin-dah-DRO-mee-us ZAH-bike-kal-ik-kuss), suggests that feathers were all in the family. That's because the newly unearthed 4.5-foot-long (1.5 meter) two-legged runner was an "ornithischian" beaked dinosaur, belonging to a group ancestrally distinct from past theropod discoveries. "Probably that means the common ancestor of all dinosaurs had feathers," says study lead author Pascal Godefroit of the Royal Belgian Institute of Natural Science in Brussels. "Feathers are not a characteristic [just] of birds but of all dinosaurs." (Related: "Dinosaur Feathers Changed With Age.")

The fossils, which included six skulls and many more bones, greatly broaden the number of families of dinosaurs sporting feathers—downy, ribboned, and thin ones in this case—indicating that plumes evolved from the scales that covered earlier reptiles, probably as insulation. In addition to its feathers, Kulindadromeus also had scales, notably arched ones that appeared in rows on its long tail.  "It's really fantastic that dinosaurs with 'fluff' are found outside of China," says paleontologist Jakob Vinther of the United Kingdom's University of Bristol, who was not on the discovery team. "The material and specimens are nothing short of fantastic; their age and sheer number are rarely to be expected."

Kulindadromeus adds a whole new dimension to understanding feather evolution, Vinther says, pointing to the fact that the three feather types found as imprints with the fossils are different from ones found on feathered dinosaurs or modern birds.

What exactly did all these different feathers do? "I don't know; nobody knows for sure," Godefroit says. "These animals couldn't fly, that's all we can tell you."

Jurassic Peeps

During the Jurassic, Kulindadromeus lived near what is now Siberia's Kulinda River, sporting feathery tufts on its legs and elbows, as well as more streamlined feathers on its back. Its shins had "ribbon-shaped" feathers of a type never seen before.

At least six skulls of the species, along with hundreds of bones, have turned up in a fossil bed that was once a lake bottom and is now a Siberian hillside. Most of the fossils were juveniles, which suggests that they died in single events, not in a mass catastrophe, according to Godefroit.
The dinosaur's name essentially means "Kulinda River running dinosaur." Zabaikalsky Krai is the region of Siberia where it was discovered (which explains its species name, zabaikalicus). "There were lakes and there were volcanoes there, lots of volcanoes," Godefroit says. The plant-eating dinosaurs likely died and fell to the lake bottom, where eruptions soon after covered them with a fine ash. That is what preserved the feather imprints with the fossil bones. "We don't know how big this fossil bed is, and it is likely we will find more when we go back," Godefroit says.

The Feather Connection

The scales on Kulindadromeus resemble the scaly skin seen on some birds, the study says, which also argues for a deep genetic root linking dinosaurs to birds.

Two earlier ornithischian dinosaur discoveries, both from China, had hinted that featherlike bristles had covered dinosaurs, notes paleontologist Stephen Brusatte of the United Kingdom's University of Edinburgh. "But the new Siberian fossils are the best example yet that some ornithischian [beaked] dinosaurs had feathers, so it wasn't only the theropods that had downy coats," Brusatte says. "This does mean that we can now be very confident that feathers weren't just an invention of birds and their closest relatives, but evolved much deeper in dinosaur history," he adds. "I think that the common ancestor of dinosaurs probably had feathers, and that all dinosaurs had some type of feather, just like all mammals have some type of hair."

Even so, Godefroit suggests that the largest dinosaurs likely had the fewest feathers, as they wouldn't have needed them for insulation. "Just like elephants in Africa don't need fur," he says.

Sunday, July 20, 2014

Setting the Record Straight on Penguins

by Claire Christian

The way climate change research is reported in the media can be confusing, even if it’s part of your job to keep up with the latest findings. As many, many commentators, scientists, and fake news anchors have noted, this unfortunately means that people think that climate change, if it exists, is some sort of scam cooked up by environmentalists who want to stop doing fun things like removing mountaintops and dumping them into streams so we can get more coal to burn. The truth is that climate change is a complex phenomenon. If you don’t understand this, you are likely to run into trouble when you read news stories about scientific research, sometimes even when those stories are really not about proving or disproving climate change. Take this post, for example. The writer completely misrepresents the results of a recent global Adélie survey by Lynch and LaRueand fans the flames of climate denialism.

The post suggests that this research and other studies indicate that penguins are doing super great under climate change, so why can’t we all stop worrying? In fact, these studies don’t say that at all. We know this because we actually talked to the researchers involved. To clarify a few technical points, the survey by Lynch and LaRue demonstrates that the known breeding population of Adélie penguins is 53% larger than was previously estimated in 1993. As the paper points out, this increase in known breeding population is roughly divided between growth at known populations and the discovery of several new populations, the latter of which include some populations that were so remote that they may have simply been missed in previous surveys. Nevertheless, the survey results do suggest that the populations of breeding Adélie penguins in East Antarctica and in the Ross Sea have grown over the last several decades, and these increases in abundance have more than offset the losses previously reported on the Antarctic Peninsula (and confirmed by this recent study).

These kinds of results are not particularly surprising to people who follow Antarctic scientific research closely. Antarctica is a big place, and climate change affects different regions of the continent differently. The Antarctic Peninsula is warming more rapidly than other Antarctic areas, and more rapidly than the rest of the world, save, perhaps, for the Arctic. So although the total number of Adélie penguins has not declined, climate change is still having a measurable impact on Antarctica. This may be good for penguins in some areas like East Antarctica and the Ross Sea, but it doesn’t mean that warmer temperatures are necessarily a Good Thing for Adélies, the continent as a whole, or the planet.

In fact, the authors note that one climate-related explanation for increasing populations may be glacial retreat (not happy news if you live in a coastal city), which opens up new habitat for Adélie penguin breeding. Study author Heather Lynch also notes, “That climate change may cause both increases and decreases in Adélie penguin populations is a tribute to its utility as a biomonitor, and highlights the Adélie’s important role as an early warning system for ecological change. Adélie penguin increases have previously been linked to a growing toothfish fishery, which itself presents concerns over the influence of Southern Ocean fisheries on the Antarctic food web.” Therefore, what’s important about this study is that it establishes a “baseline for understanding future changes in abundance and distribution”, not that it proves that all is well with penguins now and forever.

Another penguin researcher (not connected with the global Adélie survey study) who was also quoted in the National Review’s blog post, Ron Naveen, told me that “To suggest that Adélies are booming or that all penguins globally are booming is bad reporting. The only way to really know that, of course, would be to compare the latest numbers with a previous survey using the same technology — and that's not possible. Rather, the big story is that we humans know more than we did because we now have more sophisticated tools in our kit. And, as a result, we have much improved baselines for detecting and assessing change.”

Species-threatening decreases in abundance, such as those projected to occur for emperor penguins within the next century (see Jenouvrier et al.'s recent paper in Nature Climate Change), remain a grave concern. Other rapid changes in abundance and distribution, including the increasing abundance reported by Lynch and LaRue, provide a reminder that both climate change and resource extraction can upset the natural ecological balance of the Southern Ocean. While the warning signs in this case represent good news for the Adélie penguin as a species, they nevertheless reflect major changes in Southern Ocean ecosystems that will have enormous consequences. Thus the Adélie penguin can be both be helped and hurt by climate change. It’s not the kind of simple message the media likes, but it’s a scientific reality.

Claire Christian
Director, Secretariat
Antarctic and Southern Ocean Coalition


King Penguin Chicks Use Collective Decision Making to Find Home Spot

king penguin chicks

King penguin chicks form groups to navigate to their home spot and they need to make collective decisions as they move along their way. As with humans or any animal, when behaving in a group, decisions have to be made. Some will be leaders, some followers. Sometimes there will be cooperation and sometimes conflict. A recent study, published in the journal Animal Behavior, provided some empirical data on how well king penguin chicks work in pairs to navigate. The study was carried out by scientists from the University of Oxford in the United Kingdom, the University of Amsterdam in The Netherlands and CFE-CNRS Montpellier in France.

King penguins live in Antarctica and an entire colony of adult king penguins may consist of a half a million breeding pairs. The colony moves in groups of different sizes on land and in the water. After eggs are hatched and chicks are born, the parents at first split up and one parent makes a very long trip (up to 400 km, which is about 250 miles) traveling to the sea in winter for food. An interesting thing to note is that when the parents return from their long trip, they can identify their own chick’s voice among the crowd, even though the crowd may consist of about 500,000 penguins. When the chicks are a bit older, then both parents leave to get food and the younger chicks are left in the care of other juveniles.

The chicks form crèches, which are chick groups, to keep warm and avoid predators, and each crèche has a specific location. Being able to navigate to the location of the crèche is crucial for a chick’s survival. When parents eventually return with food, they need to return to the locality of the home crèche to feed their young. If the chicks are not in the right place, they will not get food.

The chicks must move together to get to their home spot. The researchers in the study aimed to determine how king penguin chicks make collective decisions about which direction to move in to find the crèche. They considered the trade-off between group cohesion and individual preferences. The aim of the study was to collect empirical data on conflict resolution during navigation.

In the study, they chose to look at pairs of chicks. The scientists manipulated the levels of conflict by pairing individuals from either the same crèche (no conflict) or different crèches (conflict over desired destination). They then observed the “homing” behavior of both types of pairs. 15 pairs of same- crèche chicks and 16 pairs of different crèche chicks were studied. Each chick had a GPS system attached to their body.

The results showed whether the chicks were better at navigating to their crèche in pairs or when moving alone. The results also determined whether conflict over the desired destination changed the navigation and how the chicks resolve conflicts. Chicks from the same crèche were more precise in getting to their home crèche. Each of the king penguin chicks in a pair took turns being the leader and following. Chicks that were from different crèches were more likely to split up the pair than those pairs that were from the same crèche. The results showed that king penguin chicks use collective decision making when traveling long distances to get to their home spot.

The Scientist
BBC Nature
final source

Wednesday, July 16, 2014

Animal foraging tactics unchanged for 50 million years

July 15, 2014
University of Southampton
Animals have used the same technique to search for food that's in short supply for at least 50 million years, a new study suggests. Researchers analyzed fossilized sea urchin trails from northern Spain and found the tracks reflect a search pattern still used by a huge range of creatures today.

Fossilized sea urchin tracks at Zumaia.
Credit: Richard Twitchett / Trustees NHM

Animals have used the same technique to search for food that's in short supply for at least 50 million years, a University of Southampton-led study suggests.

Researchers analysed fossilised sea urchin trails from northern Spain and found the tracks reflect a search pattern still used by a huge range of creatures today. But this is the first example of extinct animals using such a strategy. The findings could explain why so many modern animals use the technique, and suggest the pattern may have an even more ancient origin.
Creatures including sharks, honeybees, albatrosses and penguins all search for food according to a mathematical pattern of movement called a Lévy walk -- a random search strategy made up of many small steps combined with a few longer steps. Although a Lévy walk is random, it's the most efficient way to find food when it's scarce.

David Sims, Professor of Marine Ecology at the University of Southampton and lead author of the study, says: "How best to search for food in complex landscapes is a common problem facing all mobile creatures. "Finding food in a timely fashion can be a matter of life or death for animals -- choose the wrong direction to move in often enough and it could be curtains. But moving in a random search pattern called a Lévy walk is mathematically the best way to find isolated food."

Even though a wide range of modern creatures search for food according to this pattern, scientists had no idea how the pattern came about, until now. Professor Sims and colleagues from the University of Southampton, NERC's National Oceanography Centre, Rothamsted Research, VU University Amsterdam and the Natural History Museum analysed the fossilised Eocene-era tracks that were made by sea urchins that lived on the deep sea floor around 50 million years ago. The long trails are preserved in rocky cliffs in a region called Zumaia in northern Spain.

"Finding the signature of an optimal behaviour in the fossil record is exceedingly rare and will help to understand how ancient animals survived very harsh conditions associated with the effects of dramatic climate changes," says Professor Sims, who is currently seconded to the Marine Biological Association in Plymouth. "Perhaps it's a case of when the going got tough, the tough really did get going." "The patterns are striking, because they indicate optimal Lévy walk searches likely have a very ancient origin and may arise from simple behaviours observed in much older fossil trails from the Silurian period, around 440 million years ago," he adds.
Professor Richard Twitchett of the Natural History Museum and co-author of the study adds: "It's amazing to think that 50 million-year-old fossil burrows and trails have provided us with the first evidence of foraging strategies in animals that live on and in the deep-sea floor -- studies which would be nearly impossible and very expensive to do in modern oceans. "Trace fossils are remarkable and beautiful records of the movements of ancient animals, which have been frozen in time and tell us so much about the evolution of life on Earth and the environments of the past."

The researchers think the collapse of primary producers, such as phytoplankton, and widespread food scarcity caused by mass extinctions, which show up in the fossil record, could have triggered the evolution of Lévy-like searches.

The Eocene lasted from 56 to 33.9 million years ago, and began as a time of global warming, with temperatures soaring across the planet.

Lévy walks aren't just confined to animals; our ancient hunter-gatherer ancestors used exactly the same approach, as do modern hunter-gatherers in northern Tanzania.

The study is published in The Proceedings of the National Academy of Sciences.

Story Source:
The above story is based on materials provided by University of Southampton. Note: Materials may be edited for content and length.

Journal Reference:
  1. D. W. Sims, A. M. Reynolds, N. E. Humphries, E. J. Southall, V. J. Wearmouth, B. Metcalfe, R. J. Twitchett. Hierarchical random walks in trace fossils and the origin of optimal search behavior. Proceedings of the National Academy of Sciences, 2014; DOI: 10.1073/pnas.1405966111

University of Southampton. "Animal foraging tactics unchanged for 50 million years." ScienceDaily. ScienceDaily, 15 July 2014. <>.

Friday, July 11, 2014

Researchers use genome analysis to understand how King Penguins came to breed on Crozet Islands

Jun 11, 2014 by Bob Yirka report
Researchers use genome analysis to understand how King Penguins came to breed on Crozet Islands
Past demographic trend of the king penguin colony of ‘La Baie du Marin’ on Possession Island, Crozet archipelago: median value (red) and 95% confidence interval ( pale red). Credit: Proceedings of the Royal Society B, DOI: 10.1098/rspb.2014.0528
( —A team made up of researchers from several European countries has used DNA analysis to better understand how it was that King Penguins came to breed on the Crozet Islands. In their paper published in Proceedings of the Royal Society B, the team describes how they managed to gather DNA samples from King Penguins without disturbing them and how analyzing what they found helped to reveal how the penguins came to colonize the Crozet Islands.

King Penguins are the second largest penguins and live and breed on islands north of Antarctica—most predominantly the Crozet Islands in the southern Indian Ocean. In this new effort the researchers sought to learn more about the history of the penguins on the islands, which they hoped would help in discovering what might happen to them as global warming causes changes to their environment.

The research team ventured to one of their island breeding grounds and snuck chicks out from under their watchful parents, replacing them temporarily with fake eggs. In addition to taking physical measurements, blood samples were taken from each of the chicks before they were returned to their parents, apparently none the worse for the wear. The team then analyzed over 65,000 snippets of DNA obtained from eight of the chicks. Their genomes revealed that the penguins had existed as a small group until about 15,000 years ago—after that, their population soared. This time period, the researchers note, coincides with the end of the last ice age.

As the ice abated, conditions for the penguins became ideal. When taking care of their young, adults swim 250 miles offshore to what is known as the polar front—a place where cold polar water collides with warm tropical waters. There the penguins fill up on lanternfishes, returning every three to five days to feed their chicks. In the winter, the adults swim even farther, traveling over 600 miles to find food.

Unfortunately, for the penguins, as the planet heats up, some climate models suggest it's likely the site of the polar front will move farther south, perhaps taking food out of reach of adults who need to return to breeding grounds to feed their offspring. Thus, the fate of King Penguins, could very well be in doubt.

More information: Paper: rspb.royalsocietypublishing.or… .1098/rspb.2014.0528
Journal reference: Proceedings of the Royal Society B search and more info


Rise and fall of prehistoric penguin populations charted

Jun 12, 2014
Rise and fall of prehistoric penguin populations charted
A pair of Gentoo penguins. Credit: Gemma Glucas
A study of how penguin populations have changed over the last 30,000 years has shown that between the last ice age and up to around 1,000 years ago penguin populations benefitted from climate warming and retreating ice. This suggests that recent declines in penguins may be because ice is now retreating too far or too fast.

An international team, led by scientists from the Universities of Southampton and Oxford, has used a genetic technique to estimate when current genetic diversity arose in and to recreate past population sizes. Looking at the 30,000 years before human activity impacted the climate, as Antarctica gradually warmed, they found that three species of penguin; Chinstrap, Adélie and southern populations of Gentoo penguins increased in numbers. In contrast, Gentoo penguins on the Falkland Islands were relatively stable, as they were not affected by large changes in ice extent.
A report of the research is published in the journal Scientific Reports.

Lead author of the paper, Gemma Clucas, from Ocean and Earth Sciences at the University of Southampton comments: "Whereas we typically think of penguins as relying on ice, this research shows that during the last there was probably too much ice around Antarctica to support the large populations we see today. The penguins we studied need ice-free ground to breed on and they need to be able to access the ocean to feed. The extensive ice-sheets and sea ice around Antarctica would have made it inhospitable for them.
Rise and fall of prehistoric penguin populations charted
A Chinstrap penguin. Credit: Dr Tom Hart
"What is particularly interesting is that after the ice age, all of these were climate change 'winners', that is to say the warming climate allowed them to expand and increase in number. However, this is not the pattern we're seeing today. Adélie and Chinstrap penguins appear to be declining due to climate change around the Antarctic Peninsula, so they've become 'losers'. Only the Gentoo penguin has continued to be a 'winner' and is expanding its range southward."

Dr Tom Hart of the University of Oxford's Department of Zoology, an author of the paper, continues: "We are not saying that today's warming climate is good for penguins, in fact the current decline of some penguin species suggests that the warming climate has gone too far for most penguins.
"What we have found is that over the last 30,000 years different penguin species have responded very differently to a gradually warming world, not something we might expect given the damage current rapid warming seems to be doing to penguins' prospects."
Rise and fall of prehistoric penguin populations charted
A group of Adélie penguins. Credit: Dr Tom Hart
To estimate changes in penguin genetic diversity, the researchers collected feathers and blood samples from 537 penguins in colonies around the Antarctic Peninsula. The scientists then sequenced a region of mitochondrial DNA that evolves relatively quickly. Using the rate of mutation of this region of DNA as a calibration point, the researchers were able to chart how the size of these populations has varied over time. The team working on the project included scientists from the British Antarctic Survey and also US scientists from Oceanites Inc, Woods Hole Oceanographic Institution, and the University of North Carolina, Wilmington.

"During the last ice age Antarctica was encircled by 100 per cent more winter sea ice than today," says Dr Tom Hart. "As ice retreated, these penguins had access to more breeding sites and more open ocean to feed."

More information: A reversal of fortunes: climate change 'winners' and 'losers' in Antarctic Peninsula penguins, Scientific Reports, 2014.


Adélie penguin population actually on the rise

July 9, 2014
Stony Brook University
The first global census of the Adélie penguin, long considered a key indicator species to monitor and understand the effects of climate change and fishing in the Southern Ocean, has revealed its population (3.79 million breeding pairs) to be 53 percent larger than previously estimated. By using high-resolution satellite imagery, researchers have applied a new method that permits regular monitoring of Adélie penguins across their entire breeding range, and by extension the health of the Southern Ocean ecosystem.

Adélie penguin incubating chicks.
Credit: Philip McDowall 


The first global census of the Adélie penguin, long considered a key indicator species to monitor and understand the effects of climate change and fishing in the Southern Ocean, has revealed its population (3.79 million breeding pairs) to be 53 percent larger than previously estimated. By using high-resolution satellite imagery, Stony Brook University ecologist Heather Lynch, PhD, and conservation biologist Michelle LaRue, PhD, of the University of Minnesota, have applied a new method that permits regular monitoring of Adélie penguins across their entire breeding range, and by extension the health of the Southern Ocean ecosystem. Their findings are published in The Auk, Orinthological Advances.
Ecologists have been tracking Adélie penguin population declines on the Antarctic Peninsula for decades but have found conflicting trends elsewhere in their breeding range. Lynch and LaRue's new paper, titled "First global census of the Adélie Penguin," finally puts all of these scattered pieces of information into a global perspective, finding that Adélie populations at the global scale appear to be growing. Key to identifying the colonies -- including the discovery of 17 populations not known to exist -- was use of satellite imagery to pinpoint the spectral characteristics of the excrement (called guano) of Adélies, a way to clearly identify the species' breeding grounds. The research has implications to better inform policy makers and scientists regarding Marine Protected Areas and climate change.

"We believe this is a landmark study with data that provides not only information on the population dynamics of Adélie penguins but injects critically needed information into the ongoing negotiations regarding the implementation of Marine Protected Areas in the Southern Ocean," said Dr. Lynch, Assistant Professor of Ecology & Evolution at Stony Brook University and a leading researcher using the increasingly popular technique of high-resolution satellite imagery to map the presence and abundance of Antarctic seabirds.

Over the past several years, the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) has discussed the establishment of a series of Marine Protected Areas surrounding Antarctica and the sub-Antarctic islands. Dr. Lynch explained that Adélie penguins are not only themselves a species of conservation concern, but their distribution and abundance globally also reflect the distribution of their marine prey -- primarily krill and fish.

"Our finding of a 53 percent increase in Adélie penguin breeding abundance compared to 20 years ago suggests that estimates of krill consumption by this species may be seriously underestimated. Leaving enough prey for natural krill predators is an important element in ensuring fisheries proceed sustainably, and for the first time we have a global map of Adélie abundance that can be used by CCAMLR," added Dr. Lynch. "Not only do we have a comprehensive baseline that can be updated and improved in the future, but we've identified a method for monitoring this important species at a global scale."

Other key findings from the global census include:
  • High-resolution satellite imagery can be effectively used to get near real-time information about penguin populations and their distribution.
  • The 53 percent increase in known abundance is roughly equally divided between genuine growth of known colonies and the discovery of, or first population estimates at, previously unknown or unsurveyed colonies.
  • Stable or growing populations of Adélie penguins in Eastern Antarctica and the Ross Sea more than offset the rapid declines witnessed on the Antarctic Peninsula, where climate change has significantly changed the timing and decreased the extent of sea ice.
  • The researchers discovered 17 previously unknown Adélie colonies. The survey did not find 13 previously known colonies, 8 of which were declared extirpated.
While we celebrate the news that Adélie penguin populations are thriving, learning of these population booms reinforces the need to protect the Antarctic food web," said Andrea Kavanagh, director of The Pew Charitable Trusts' global penguin conservation campaign. The project's aim is to restore and protect penguin breeding and feeding grounds in coastal waters throughout the Southern Hemisphere, and to create large no-take marine reserves in the Southern Ocean. "We call on CCAMLR to implement a strong ecosystem management plan for the Antarctic krill, so that all penguin species have access to abundant protein and can continue to thrive."

Drs. Lynch and LaRue used high-resolution satellite imagery, recent ground counts and other techniques to identify Adélie Penguin colonies over the 5,500 kilometer Antarctic coastline in the lowest regions of the Antarctic Ocean, or Southern Ocean -- a distance 40 percent longer than from New York to Los Angeles.

There has been an exploding interest among scientists internationally in using satellites to survey Antarctic species such as penguins, seals and whales. The relative simplicity of the landscape makes satellite-based surveys an exciting way to look at Antarctic biology at scales not previously thought possible, paving the way for Antarctica to become an unlikely hotbed of discovery for understanding the population dynamics of seabirds and marine mammals.

Story Source:
The above story is based on materials provided by Stony Brook University. Note: Materials may be edited for content and length.

Stony Brook University. "Happy Feet III: Adélie penguin population actually on the rise." ScienceDaily. ScienceDaily, 9 July 2014. <>.

Birdlike fossil challenges notion that birds evolved from ground-dwelling dinosaurs

July 9, 2014
The re-examination of a sparrow-sized fossil from China challenges the commonly held belief that birds evolved from ground-dwelling theropod dinosaurs that gained the ability to fly. The birdlike fossil is actually not a dinosaur, as previously thought, but much rather the remains of a tiny tree-climbing animal that could glide.

This is a skeletal reconstruction of Scansoriopteryx with outlines to indicate the extent of the feathers.
Credit: Stephen A. Czerkas

The re-examination of a sparrow-sized fossil from China challenges the commonly held belief that birds evolved from ground-dwelling theropod dinosaurs that gained the ability to fly. The birdlike fossil is actually not a dinosaur, as previously thought, but much rather the remains of a tiny tree-climbing animal that could glide, say American researchers Stephen Czerkas of the Dinosaur Museum in Blanding, Utah, and Alan Feduccia of the University of North Carolina. The study appears in Springer's Journal of Ornithology.

The fossil of the Scansoriopteryx (which means "climbing wing") was found in Inner Mongolia, and is part of an ongoing cooperative study with the Chinese Academy of Geological Sciences. It was previously classified as a coelurosaurian theropod dinosaur, from which many experts believe flying dinosaurs and later birds evolved. The research duo used advanced 3D microscopy, high resolution photography and low angle lighting to reveal structures not clearly visible before. These techniques made it possible to interpret the natural contours of the bones. Many ambiguous aspects of the fossil's pelvis, forelimbs, hind limbs, and tail were confirmed, while it was discovered that it had elongated tendons along its tail vertebrae similar to Velociraptor.
Czerkas and Feduccia say that Scansoriopteryx unequivocally lacks the fundamental structural skeletal features to classify it as a dinosaur. They also believe that dinosaurs are not the primitive ancestors of birds. The Scansoriopteryx should rather be seen as an early bird whose ancestors are to be found among tree-climbing archosaurs that lived in a time well before dinosaurs.

Through their investigations, the researchers found a combination of plesiomorphic or ancestral non-dinosaurian traits along with highly derived features. It has numerous unambiguous birdlike features such as elongated forelimbs, wing and hind limb feathers, wing membranes in front of its elbow, half-moon shaped wrist-like bones, bird-like perching feet, a tail with short anterior vertebrae, and claws that make tree climbing possible. The researchers specifically note the primitive elongated feathers on the forelimbs and hind limbs. This suggests that Scansoriopteryx is a basal or ancestral form of early birds that had mastered the basic aerodynamic maneuvers of parachuting or gliding from trees.

Their findings validate predictions first made in the early 1900's that the ancestors of birds were small, tree-dwelling archosaurs which enhanced their incipient ability to fly with feathers that enabled them to at least glide. This "trees down" view is in contrast with the "ground up" view embraced by many palaeontologists in recent decades that birds derived from terrestrial theropod dinosaurs. "The identification of Scansoriopteryx as a non-dinosaurian bird enables a reevaluation in the understanding of the relationship between dinosaurs and birds. Scientists finally have the key to unlock the doors that separate dinosaurs from birds," explained Czerkas.

Feduccia added, "Instead of regarding birds as deriving from dinosaurs, Scansoriopteryx reinstates the validity of regarding them as a separate class uniquely avian and non-dinosaurian."

Story Source:
The above story is based on materials provided by Springer. Note: Materials may be edited for content and length.

Journal Reference:
  1. Stephen A. Czerkas, Alan Feduccia. Jurassic archosaur is a non-dinosaurian bird. Journal of Ornithology, 2014; DOI: 10.1007/s10336-014-1098-9

Springer. "Birdlike fossil challenges notion that birds evolved from ground-dwelling dinosaurs." ScienceDaily. ScienceDaily, 9 July 2014. <>.

Sunday, July 6, 2014

Why Some Penguins Thrive in Climate Change

PHOTO: A Gentoo Penguin is seen in Antartica.
Penguins are on the front line of climate change, as rising global temperatures melt the ice the iconic and lovable creatures call home. Scientists who count the birds are finding that penguins are beginning to feel major impacts from the drastic changes to their habitat. 

But, perhaps surprisingly, the breeding populations of three brush-tailed species of penguins inhabiting the Western Antarctic Peninsula, where the temperatures are warmest, are not all falling as the ice is quickly melting. "We know two of the three penguin species in the peninsula, chinstrap and Adélie, are declining significantly in a region where, in the last 60 years, it's warmed by 3 degrees C. (5 degrees F.) annually and by 5 degrees C. (9 degrees F.) in winter," said Ron Naveen, the founder of Oceanites, a U.S. based non-profit and scientific research organization. He oversees the Antarctic Site Inventory which monitors penguin populations. 

A third species, however, has not been losing numbers and in fact has even been expanding its range.
Counting penguins in the wild is a complicated art. Naveen's team makes repeated visits every year to the Antarctic Peninsula from November to February when egg-laying and chick creching are at their peak. 

Since 1994, he has conducted 1,421 visits to the peninsula and collected data from 209 sites.
Naveen and fellow penguin counter Heather Lynch of Stony Brook University say the warming climate and the consequent loss of sea ice are contributing to the decline in Adelie and chinstrap, because the two species are dependent on the ice. Warming temperature is only one part of the whole story, however, according to the Naveen. "There are a number of possibilities," he said. 

Adelies and chinstrap nest primarily near the ice and rely on krill as their main food source. These shrimp-like vertebrates live underneath the ice, feeding on the algae that grows there. As the ice retreats, the krill disappear. 

PHOTO: A Gentoo Penguin is seen in Antartica.
Darci Amundson Photography
PHOTO: A Gentoo Penguin is seen in Antarctica.
Other factors such as commercial overfishing and the expanding population of humpback whales, which also feed on krill, may also contribute to the loss of their main food source. By contrast, Gentoo penguins, the third of these species, are expanding both in numbers and in geographical range, according to Naveen and Lynch's research. There are an estimated 387,000 Gentoo breeding pairs and their populations are moving southward along the peninsula. "Gentoos are an open water species and can move southward as the declining ice concentration makes new habitat available to them," Lynch said. 

Gentoos, the most flexible of the three species, will eat anything, not just krill, and can adjust their life cycle more easily in response to variable conditions. If the snow melts early, for example, they can breed earlier or relay their eggs. 

PHOTO: A Chinstrap Penguin is seen in Antartica.
Darci Amundson Photography
PHOTO: A Chinstrap Penguin is seen in Antarctica.
Naveen uses simple tools to conduct his field work -- a handheld counting device known as a tally counter, a pencil, and a notebook -- and combines the data with Lynch's work with remote sensing to ascertain as complete a count as possible. 

Lynch analyzes hi-res satellite images to help her map out and analyze contours of breeding colonies, look at biological and physical data sets to determine breeding pairs, and assess breeding populations in remote places too difficult to get to, such as some locations in the South Sandwich Islands. 

The team's combination of field work and remote sensing allowed them to get the first site-wide inventory of Penguins at Deception Island. For example, Naveen found 79,849 breeding pairs of chinstrap penguins, including 50,408 breeding pairs at Baily Head. That 2012 census, combined with data from Lynch's satellite imagery, also indicates the chinstrap population has declined 50 percent as compared to previous population estimates conducted in 1987.

PHOTO: A Chinstrap Penguin is seen in Antartica.
Darci Amundson Photography
PHOTO: A Chinstrap Penguin is seen in Antarctica.
Monitoring penguin populations in the western Antarctic Peninsula, how they shrink and grow in response to changing conditions, not only provides critical clues to how to manage the environment down there, but perhaps for us as well, Naveen said. "Are they sending us a message we should be thinking about?" he said. "Are we canaries in the coal mine?"