Friday, November 28, 2014

Ancient penguin was a giant of NZ birdlife

Jamie Morton is science reporter at the NZ Herald.


Dr Daniel Thomas holds a thigh bone from the fossil penguin which would have stood 30cm taller than an emperor penguin today (left).
Dr Daniel Thomas holds a thigh bone from the fossil penguin which would have stood 30cm taller than an emperor penguin today (left).
A giant ancient penguin far taller than any species alive today has been described for the first time after its fossil remains sat for decades inside an Auckland storage shed.

The fossilised bones of the penguin, yet to be named, were found in North Waikato in 1971, but had been largely ignored until recently rediscovered by Massey University zoologist Dr Daniel Thomas.
The unusual features of the 28-million-year-old specimen have convinced Dr Thomas it is a new species, and the first of its kind to be discovered in the North Island.

Dr Thomas estimates the bird would have stood at 1.3m - slightly taller than the ancient Kairuku penguin discovered in 2012, and about 30cm taller than today's largest penguin, the emperor. "I imagine an emperor would have run away scared," said Dr Thomas, when asked how the two birds would compare. It was likely the bird would have been a deep-diving penguin, like the emperor, and been preyed upon by sharks and dolphins.

He learned about the remains shortly after returning to New Zealand from overseas and searching through old research papers. Because there was little to compare the remains against when they were discovered, the specimens were not fully classified and were eventually shelved in a Tamaki storage shed operated by the University of Auckland. "It turned out there was a raft of other specimens as well - it was a treasure trove of some really incredible stuff."

It was when he came upon the right leg bone of the penguin - enough to immediately tell him much about the bird - that the significance of the discovery struck him. "I couldn't stop grinning, to be honest ... I was looking at this thing and thinking, how has no one worked on this for 40 years?"

Dr Thomas had the bones 3-D-scanned and sent the prints to colleague Dr Dan Ksepka in the United States for further analysis. Features in the bones of the fossil penguin were different from any of the 50 discovered so far, and Dr Thomas and his colleagues now have only to confirm its status as a juvenile or adult before they can prepare a paper for peer review.

The find was especially exciting for Dr Thomas as the fossil was recovered near where he grew up, and he sees potential for many more new discoveries to be made in the North Island. He is keen to hear from Waikato and King Country farmers with limestone quarries who could help with the hunt.

3 Penguin facts


1. An unnamed ancient penguin whose fossilised bones were recently rediscovered in an Auckland storage shed lived 28 million years ago when most of New Zealand was underwater. 2. It is likely to have stood just over 1.3m tall - slightly taller than the recently discovered ancient Kairuku penguin and 30cm taller than the largest existing penguin, the emperor.
3. It is believed to be the first specimen of its type discovered in the North Island and raises exciting possibilities of what other wonders may lie preserved inside the North Island's hills and limestone quarries.

source

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Fossil find reveals new giant penguin

Olivia Allison, Environment/Science Reporter 
28 November 2014
Scientists have discovered a new species of giant penguin that lived in waters around Waikato about 27 to 28 million years ago
Dr Daniel Thomas with  the fossil.
Dr Daniel Thomas with the fossil.
Photo: RNZ / Olivia Allison

Fossils were found in the 1970s, but scientists could not say for sure if it was a new species of penguin, so they stayed in storage at Auckland University. That is, until the invention of 3D printing.
This has allowed Massey University's Dr Daniel Thomas to scan the bones to American paleontologist Dr Daniel Ksepka. Both were then able to determine that they are "almost certain" it was a new type of giant penguin.

The penguin was dated by taking a fragment of the rock the bones were encased in and looking at fossil plankton. Records of fossil plankton are vast, so Dr Thomas said it was easier to determine the date.

Dr Thomas said penguin fossils become accessible as parts of the North Island that were once under water rose up over time. He could tell it was a giant penguin by comparing the thigh bone of the fossil to other penguins.

Emperor penguins are about 1 metre tall and have a thigh bone half the size of the fossil bone. Dr Thomas said it had been compared with another fossil giant penguin also, allowing them to guess that it was about 1.3 metres tall.

Dr Thomas said it did not appear to have any links to emperor penguins, other than the fact they were both penguins. "Because it lived so far back in time, it's not a close link - they'd be very distant relatives. Definitely not a cousin or step-cousin."

As researchers only have one leg bone and other fragments, they could not tell what body shape the penguin had or its weight. But they could guess with near certainty that it was black and white, just like penguins today.

Dr Thomas said it was likely the penguin would have been a deep diver, travelling offshore to find fish. He said the discovery was very big, as it was the first North Island fossil giant penguin to be discovered. "Africa has fossil humans, America has fossil dinosaurs, we have a few dinosaurs, but I like to think of New Zealand as a place with giant penguins. It feeds into the idea that New Zealand is really special."

source

Thursday, November 6, 2014

Taking a deeper look at 'ancient wing'

Date:

November 5, 2014

Source:

Society of Vertebrate Paleontology

Summary:


In order to determine the feather color of ancient organisms such as Archaeopteryx, microscopic melanin-containing structures called melanosomes have been compared in a variety of living and fossil birds. However, might there be another explanation for the presence of these structures? This research uses scanning electron microscopy and high-sensitivity molecular techniques to respond to alternative interpretations and shed light -- and color -- on Jurassic feathers.

The fossil feather and skeleton of the iconic dinosaur Archaeopteryx.
Credit: Copyright Museum für Naturkunde Berlin



Reconstructing ancient life has long required a certain degree of imagination. This is especially true when considering the coloration of long-extinct organisms. However, new methods of investigation are being incorporated into paleontology that may shed light (and color) on fossils. Research presented at the recent Society of Vertebrate Paleontology meeting shows the importance of using new imaging technologies in reconstructing the color of Archaeopteryx, one of the most famous and important fossils species.
Ryan Carney of Brown University incorporated scanning electron microscopy in a 2012 study to identify melanosomes (melanin-containing pigment structures) in modern feathers to reconstruct the feather color of the iconic Archaeopteryx, the so-called "missing link" -- or more appropriately, evolutionary intermediate -- between non-avian dinosaurs and birds. Archaeopteryx has also been referred to as the "Mona Lisa of paleontology," a fossil taxon with great scientific, historical, and cultural importance.

However, after Carney's original publication, there has been some recent controversy with respect to two competing papers that offer alternative interpretations. The first was that the Archaeopteryx feather was both black and white, based on the distribution of organic sulfur imaged via synchrotron. The second was that the fossilized microbodies in the feather represent bacteria instead of melanosomes, given their similarities in size and shape.

The results of Carney's new research address these alternative interpretations and provide new insights into the Archaeopteryx feather. "The inner vane of the Archaeopteryx feather, which they claimed was white, we instead found to be packed with black melanosomes," said Carney. "This is critical because white feather color is only produced in the absence of melanosomes."

Furthermore, Carney and his Swedish colleagues have investigated the preservation of melanosomes in a variety of other fossils, utilizing additional new analytical methods such as Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS). Carney added, "We are not contending that every fossilized microbody is a melanosome. However, this new chemical method has allowed us to detect actual melanin molecules, which are associated with the melanosome-like microbodies in fossilized feathers and skin, from both terrestrial and marine environments. This integrated structural and direct chemical evidence provides the definitive proof that melanosomes can indeed be preserved in the fossil record."

Together, this new research paints the final picture of the famous wing feather as matte black with a darker tip, coloration that would have provided structural advantages to the plumage during this early evolutionary stage of dinosaur flight.

The application of such high-sensitivity analytical techniques is ushering in a new age of paleontological investigations. What once was artistic license, such as the appearance of ancient organisms, is now revealing itself in living color. As analytical methods in paleontology keep a pulse on technological advancements, we will continue to gain understanding of how fossil animals once lived and looked.

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


Society of Vertebrate Paleontology. "Taking a deeper look at 'ancient wing'." ScienceDaily. ScienceDaily, 5 November 2014. <www.sciencedaily.com/releases/2014/11/141105084824.htm>.

How the shape of eggs can help explain the evolutionary history of birds

Date:
November 5, 2014
Source:
University of Lincoln
Summary:
The eggs of amniotes - mammals, reptiles and birds – come in a remarkable variety of shapes and sizes. Evolutionary biologists have now addressed shape variety in terrestrial vertebrates' eggs, pinpointing morphological differences between the eggs of birds and those of their extinct relatives, the theropod dinosaurs.








Theropod Troodon clutch.
Credit: Charles Deeming


The eggs of amniotes -- mammals, reptiles and birds -- come in a remarkable variety of shapes and sizes.
Evolutionary biologists have now addressed shape variety in terrestrial vertebrates' eggs, pinpointing morphological differences between the eggs of birds and those of their extinct relatives, the theropod dinosaurs.

Researchers from the University of Lincoln, UK, examined eggshell geometry from the transition of theropods -- a sub-order of the Saurischian dinosaurs -- into birds, based on fossil records and studies of their living species.

The results suggest that the early birds from the Mesozoic (252 to 66 million years' ago) laid eggs that had different shapes to those of modern birds. This may suggest that egg physiology and embryonic development was different in the earliest birds and so this may have implications for how some birds survived the Cretaceous-Palaeocene extinction event that wiped out the dinosaurs.

Their findings are published in the journal Royal Society Open Science.

Author Dr Charles Deeming, from Lincoln's School of Life Sciences, explained: "These results indicate that egg shape can be used to distinguish between different types of egg-laying vertebrates. More importantly they suggest Mesozoic bird eggs differ significantly from modern day bird eggs, but more recently extinct Cenozoic birds do not. This suggests that the range of egg shapes in modern birds had already been attained in the Cenozoic."

The origin of the amniotic egg (an egg which can survive out of water) is one of the key adaptations underpinning vertebrates' transition from sea to land more than 300 million years ago. Modern amniotic eggs vary considerably in shape and size and it is believed this variety may reflect the different patterns of egg formation and development in these taxa.
Dr Deeming added: "From a biological perspective, it is self-evident that different egg shapes by birds, both past and present, might be associated with different nesting behaviours or incubation methods. However, hardly any research has been carried out on this topic and fossil data are insufficient to draw firm conclusions. We hope that future discoveries of associated fossil eggs and skeletons will help refine the general conclusions of this work."

Dr Deeming and co-author Dr Marcello Ruta, also from the University of Lincoln, are now investigating how the highly variable amounts of yolk and albumen (egg white) in eggs of different species could be a possible determinant of bird egg shape.

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

Journal Reference:
  1. D. Charles Deeming and Marcello Ruta. Egg shape changes at the theropod-bird transition, and a morphometric study of amniote eggs. Royal Society Open Science, 2014 DOI: 10.1098/rsos.140311

University of Lincoln. "How the shape of eggs can help explain the evolutionary history of birds." ScienceDaily. ScienceDaily, 5 November 2014. <www.sciencedaily.com/releases/2014/11/141105084724.htm>.

Wednesday, November 5, 2014

Could hand-reared penguins help seed new colonies?


Along the Western Cape of South Africa lives a group of endangered African penguins. These penguins breed from February through September, and then moult sometime between September and January. During the moulting period, the penguins are deprived of their waterproof feathers. That’s 21 days in which they’re prevented from diving for food and must rely on stored up fat for nutrition until their new feathers grow in. But if they begin the moult while they still have penguins in the nest, the chicks – who rely on their parents for food – could go hungry.

To help guard against starvation, the Southern African Foundation for the Conservation of Coastal Birds (SANCCOB) rescues these so-called “abandoned” penguins chicks whose parents just went and started moulting, leaving their precious babies to slowly starve to death. Once the penguin chicks grow up a bit, SANCCOB releases them back into their breeding colonies. In 2007, they cared for more than 480 such chicks, and nearly twice as many the year before.

What University of Cape Town animal demographer Richard B. Sherley wanted to know was whether the birds who wound up being released back into the wild fared at least as well as those who were raised by their parents, as nature intended.

In both 2006 and 2007, SANCOBB rescued a number of orphaned Africa penguin chicks. Many of them were starving because their parents began to moult, others were abandoned by their parents after their nest sites became flood, and still others were left alone after their parents themselves had to be rehabilitated due to oiling. Of those brought in for care, 91% were released in 2006, and 73% were healthy enough to release in 2007.

Before being released, many of the birds were banded so that researchers could track their progress. The researchers estimated that 11% of rehabilitated and released penguins were recruited into breeding populations, with around 14% surviving to breeding age.

These may seem like low odds, but they compare favorably to both the likelihood of penguin survival following oil spill-related rehabilitation, and even to the likelihood of survival when penguin chicks are reared by their own parents, free of human intervention.

Half of those who were confirmed breeders had returned to their birth colony, while half had joined other colonies. That suggests that hand-rearing is a viable, if labor-intensive and costly, means to bolster the size of individual penguin colonies. It also suggests that abandoned chicks could be a useful way to help establish new breeding colonies, in better areas. “As the situation for African penguin has continued to deteriorate on the West Coast, plans have been developed to use conservation translocations to establish new breeding colonies in areas of higher prey availability along the South African coast,” write the researchers.

Despite the fact that half of penguins in the current study found their way back to their birth colony, penguins aren’t stupid. “Translocated individuals will take some prospecting behaviour to evaluate the quality of their new habitat,” Sherley explains. If they’re released into a high-quality site with lots of prey, they might just stay.

It’s not just that penguins are adorable, iconic critters. As a group, seabirds are some of the most endangered birds on the planet. Nearly half of seabird species are declining, with nearly a third having earned a spot on the IUCN Red List. African penguins in particular declined by some seventy percent in the last 15 years, mainly owing to declines in their preferred prey, small baitfish like sardine and anchovy. By combining the hand-rearing of malnourished chicks with the establishment of new colonies at more optimal locations, researchers and conservationists might be able to help ensure a bright, fishy future for these most charismatic of seabirds. 

– Jason G. Goldman | 05 November 2014

Source: Sherley R.B., Venessa Strauss, Deon Geldenhuys, Les G. Underhill & Nola J. Parsons (2014). Hand-Rearing, Release and Survival of African Penguin Chicks Abandoned Before Independence by Moulting Parents, PLoS ONE, 9 (10) e110794. DOI: http://dx.doi.org/10.1371/journal.pone.0110794

Header image: shutterstock.com

source 

Saturday, November 1, 2014

Seeing dinosaur feathers in a new light

Date:
October 30, 2014
Source:
Universität Bonn
Summary:
Why were dinosaurs covered in a cloak of feathers long before the early bird species Archaeopteryx first attempted flight? Researchers postulate that these ancient reptiles had a highly developed ability to discern color. Their hypothesis: The evolution of feathers made dinosaurs more colorful, which in turn had a profoundly positive impact on communication, the 
selection of mates and on dinosaurs’ procreation.


Feathers close up (stock image). The researchers' hypothesis: The evolution of feathers made dinosaurs more colorful, which in turn had a profoundly positive impact on communication, the selection of mates and on dinosaurs' procreation.
Credit: © thawats / Fotolia
Why were dinosaurs covered in a cloak of feathers long before the early bird species Archaeopteryx first attempted flight? Researchers from the University of Bonn and the University of Göttingen attempt to answer precisely that question in their article "Beyond the Rainbow" in the latest issue of the journal Science. The research team postulates that these ancient reptiles had a highly developed ability to discern color. Their hypothesis: The evolution of feathers made dinosaurs more colorful, which in turn had a profoundly positive impact on communication, the selection of mates and on dinosaurs' procreation.
The suggestion that birds and dinosaurs are close relatives dates back to the 19th century, the time when the father of evolutionary theory, Charles Darwin, was hard at work. But it took over 130 years for the first real proof to come to light with numerous discoveries of the remains of feathered dinosaurs, primarily in fossil sites in China. Thanks to these fossil finds, we now know that birds descend from a branch of medium-sized predatory dinosaurs, the so-called theropods. Tyrannosaurus rex and also velociraptors, made famous by the film Jurassic Park, are representative of these two-legged meat eaters. Just like later birds, these predatory dinosaurs had feathers -- long before Archaeopteryx lifted itself off the ground. But why was this, particularly when dinosaurs could not fly?

Dinosaurs' color vision

"Up until now, the evolution of feathers was mainly considered to be an adaptation related to flight or to warm-bloodedness, seasoned with a few speculations about display capabilities" says the article's first author, Marie-Claire Koschowitz of the Steinmann Institute for Geology, Mineralogy and Paleontology at the University of Bonn. "I was never really convinced by any of these theories. There has to be some particularly important feature attached to feathers that makes them so unique and caused them to spread so rapidly amongst the ancestors of the birds we know today," explains Koschowitz. She now suggests that this feature is found in dinosaurs' color vision. 

After analyzing dinosaurs' genetic relationships to reptiles and birds, the researcher determined that dinosaurs not only possessed the three color receptors for red, green and blue that the human eye possesses, but that they, like their closest living relatives, crocodiles and birds, were probably also able to see extremely short-wave and ultraviolet light by means of an additional receptor. "Based on the phylogenetic relationships and the presence of tetrachromacy in recent tetrapods it is most likely that the stem species-of all terrestrial vertebrates had photo receptors to detect blue, green, red and uv," says Dr. Christian Fischer of the University of Göttingen.

This makes the world much more colorful for most animals than it is for human beings and other mammals. Mammals generally have rather poor color vision or even no color vision at all because they tended to be nocturnal during the early stages of their evolution. In contrast, numerous studies on the social behavior and choice of mates among reptiles and birds, which are active during the day, have shown that information transmitted via color exerts an enormous influence on those animals' ability to communicate and procreate successfully.

Feathers allowed for more visible signals than did fur

We know from dinosaur fossil finds that the precursors to feathers resembled hairs similar to mammals' fur. They served primarily to protect the smaller predatory dinosaurs -- which would eventually give rise to birds -- from losing too much body heat. The problem with these hair-like forerunners of feathers and with fur is that neither allow for much color, but tend instead to come in basic patterns of brown and yellow tones as well as in black and white. Large flat feathers solved this shortcoming by providing for the display of color and heat insulation at the same time. Their broad surface area, created by interlocked strands of keratin, allows for the constant refraction of light, which consequently produces what is referred to as structural coloration. This refraction of light is absolutely necessary to produce colors such as blue and green, the effect of metallic-like shimmering or even colors in the UV spectrum. "Feathers enable a much more noticeable optical signaling than fur would allow. Iridescent birds of paradise and hummingbirds are just two among a wealth of examples," explains Koschowitz.

This work means we must see the evolution of feathers in a whole new light. They provided for a nearly infinite variety of colors and patterns while simultaneously providing heat insulation. Prof. Dr. Martin Sander of the University of Bonn's Steinmann Institute summarizes the implications of this development: "This allowed dinosaurs to not only show off their colorful feathery attire, but to be warm-blooded animals at the same time -- something mammals never managed."

Story Source:

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

Journal Reference:
  1. M.-C. Koschowitz, C. Fischer, M. Sander. Beyond the rainbow. Science, 2014; 346 (6208): 416 DOI: 10.1126/science.1258957


Universität Bonn. "Seeing dinosaur feathers in a new light." ScienceDaily. ScienceDaily, 30 October 2014. <www.sciencedaily.com/releases/2014/10/141030100714.htm>.

Friday, October 24, 2014

U of Delaware study connects penguin chick weights to local weather conditions


UD researchers have reported a connection between local weather conditions and the weight of Adélie penguin chicks.

Penguin chicks

Oct. 24, 2014--Adélie penguins are an indigenous species of the West Antarctic Peninsula (WAP), one of the most rapidly warming areas on Earth. Since 1950, the average annual temperature in the Antarctic Peninsula has increased 2 degrees Celsius on average, and 6 degrees Celsius during winter.
As the WAP climate warms, it is changing from a dry, polar system to a warmer, sub-polar system with more rain.

University of Delaware oceanographers recently reported a connection between local weather conditions and the weight of Adélie penguin chicks in an article in Marine Ecology Progress Series, a top marine ecology journal.

Penguin chick weight at the time of fledgling, when they leave the nest, is considered an important indicator of food availability, parental care and environmental conditions at a penguin colony. A higher chick mass provides the chick a better likelihood of surviving and propagating future generations.

In the study, Megan Cimino, a UD doctoral student in the College of Earth, Ocean, and Environment and the paper’s lead author, compared data from 1987 to 2011 related to the penguin’s diet, the weather and the large-scale climate indices to see if they could correlate year-to-year penguin chick weight with a particular factor. She also evaluated samples from the penguin’s diet to determine what they were eating. “The ability of a penguin species to progress is dependent on the adults’ investment in their chicks,” said Matthew Oliver, an associate professor of marine science and policy and principal investigator on the project. “Penguins do a remarkable job of finding food for their chicks in the ocean’s dynamic environment, so we thought that the type and size distribution of food sources would impact chick weight.”

Impact of weather and climate

Instead, the study revealed that weather and overall atmospheric climate seemed to affect weights the most. In particular, local weather —  including high winds, cold temperatures and precipitation, such as rain or humidity — had the largest impact on penguin chick weight variations over time. For example, westerly wind and air temperature can cause a 7-ounce change in average chick weights, as compared to 3.5-ounce change caused by wind speed and precipitation.  A 7-ounce decrease in chick weight could be the difference between a surviving and non-surviving chick.

Cimino explained that while penguins do build nests, they have no way of building nests that protect the chicks from the elements. This leaves penguin chicks unprotected and exposed while adult penguins are away from the nest. Precipitation, while not considered a key variable, can cause chick plumage to become damp or wet and is generally a major factor in egg and chick mortality and slow growth. “It’s likely that weather variations are increasing the chicks’ thermoregulatory costs; and when they are cold and wet, they have to expend more energy to keep warm,” she said.

The wind can also affect the marine environment, she continued, mixing up the water column and dispersing the krill, a penguin’s main source of food, which may cause parent penguins to remain at sea for longer periods of time and cause chicks to be fed less frequently. “This is an interesting study, because it calls into question what happens to an ecosystem when you change climate quickly: Is it just large-scale averages that change the ecosystem or do particular daily interactions also contribute to the change,” Oliver said.

Research team

Other co-authors on the paper include William Fraser and Donna Patterson-Fraser, from the Polar Oceans Research Group, and Vincent Saba, from NOAA National Marine Fisheries Service. Fraser and Patterson have been collecting data on Adélie penguins since the late 1970s, creating a strong fundamental data set that includes statistics collected over decades, even before rapid warming was observed.

By correlating the relevant environmental variables through analysis of data from sources such as space, weather stations, etc., the researchers were able to scientifically validate a potential cause for chick weight variation over time. Using big data analyses to statistically sift through the possible causes allowed the researchers to take a forensic approach to understanding the problem.

“Climate change strikes at the weak point in the cycle or life history for each different species,” Oliver said. “The Adélie penguin is incredibly adaptive to the marine environment, but climate ends up wreaking havoc on the terrestrial element of the species’ history, an important lesson for thinking about how we, even other species, are connected to the environment.” 
Cimino will return to Antarctica next month to begin working with physical oceanographers from University of Alaska and Rutgers, through funding from the National Science Foundation. Using robotics, she will investigate what parent penguins actually do in the ocean in order to gain a broader perspective on how the penguins use the marine environment. In particular, she hopes to explore other possible contributing factors to chick weight variation such as parental foraging components that were not part of this study. “It’s important for us to understand what’s going on, especially as conditions are getting warmer and wetter, because it may give us an idea of what may happen to these penguins in the future,” Cimino said.

The work reported here is supported in part through funds from the National Marine Fisheries Service, NASA and the National Science Foundation.

Article by Karen B. Roberts
Photos by Megan Cimino

Source: University of Delaware

Thursday, October 23, 2014

Upper Cretaceous Antarctica


Upper Cretaceous Antarctica, 1994, William Stout

Rescued 'abandoned' penguin chicks survival similar to colony rates -more information

Date:
October 22, 2014
Source:
PLOS
Summary:
Abandoned penguin chicks that were hand-reared and returned to the wild showed a similar survival rate to their naturally-reared counterparts.







Abandoned penguin chicks that were hand-reared and returned to the wild showed a similar survival rate to their naturally-reared counterparts, according to a study published October 22, 2014 in the open-access journal PLOS ONE by Richard Sherley from University of Cape Town and colleagues.
The Endangered African penguin population has been rapidly decreasing since 2001. In the Western Cape of South Africa, penguins breed from February to September and moult between September and January, once chicks have fledged. If adult penguins begin the moulting process, a 21 day period where they no longer have the waterproofing necessary to dive for food, with chicks in the nest, the chicks may starve. Southern African Foundation for the Conservation of Coastal Birds (SANCCOB) recovers 'abandoned' penguin chicks that are no longer being fed and cares for them until they can be reintroduced into breeding colonies. Researchers documented the care, release, and survival of over 840 and 480, in 2006 and 2007 respectively, hand-reared chicks.

Of those admitted, 91% and 73% respectively were released into the wild. Post-release juvenile and adult survival rates were similar to recent survival rates recorded for naturally-reared birds. By December 2012 researchers observed that 12 birds had bred, six at their colony of origin. The authors suggest that hand-rearing of 'abandoned' penguin chicks may be a useful conservation tool to limit mortality and to strengthen the population at specific colonies. "Over the last decade, food availability has decreased dramatically for penguins breeding in Western South Africa and many birds now struggle to rear their chicks before they need to initiate moult. Hand-reared chicks can sustain populations in the short-term and help us understand how we might create new breeding colonies in areas of higher food availability," said Dr. Sherley.

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

Journal Reference:
  1. Richard B. Sherley, Lauren J. Waller, Venessa Strauss, Deon Geldenhuys, Les G. Underhill, Nola J. Parsons. Hand-Rearing, Release and Survival of African Penguin Chicks Abandoned Before Independence by Moulting Parents. PLoS ONE, 2014; 9 (10): e110794 DOI: 10.1371/journal.pone.0110794


PLOS. "Rescued 'abandoned' penguin chicks survival similar to colony rates." ScienceDaily. ScienceDaily, 22 October 2014. <www.sciencedaily.com/releases/2014/10/141022143630.htm>.

Wednesday, October 22, 2014

Rescued 'abandoned' penguin chicks survival similar to colony rates

Posted By News On October 22, 2014
Abandoned penguin chicks that were hand-reared and returned to the wild showed a similar survival rate to their naturally-reared counterparts, according to a study published October 22, 2014 in the open-access journal PLOS ONE by Richard Sherley from University of Cape Town and colleagues.

The Endangered African penguin population has been rapidly decreasing since 2001. In the Western Cape of South Africa, penguins breed from February to September and moult between September and January, once chicks have fledged. If adult penguins begin the moulting process, a 21 day period where they no longer have the waterproofing necessary to dive for food, with chicks in the nest, the chicks may starve.

Southern African Foundation for the Conservation of Coastal Birds (SANCCOB) recovers 'abandoned' penguin chicks that are no longer being fed and cares for them until they can be reintroduced into breeding colonies. Researchers documented the care, release, and survival of over 840 and 480, in 2006 and 2007 respectively, hand-reared chicks.

Of those admitted, 91% and 73% respectively were released into the wild. Post-release juvenile and adult survival rates were similar to recent survival rates recorded for naturally-reared birds. By December 2012 researchers observed that 12 birds had bred, six at their colony of origin. The authors suggest that hand-rearing of 'abandoned' penguin chicks may be a useful conservation tool to limit mortality and to strengthen the population at specific colonies. "Over the last decade, food availability has decreased dramatically for penguins breeding in Western South Africa and many birds now struggle to rear their chicks before they need to initiate moult.

Hand-reared chicks can sustain populations in the short-term and help us understand how we might create new breeding colonies in areas of higher food availability," said Dr. Sherley.

Source: PLOS via Science Codex

Thursday, October 9, 2014

Antarctic sea ice reaches new record maximum

Date:
October 8, 2014
Source:
NASA/Goddard Space Flight Center
Summary:
Sea ice surrounding Antarctica reached a new record high extent this year, covering more of the southern oceans than it has since scientists began a long-term satellite record to map the extent in the late 1970s.









On Sept. 19, 2014, the five-day average of Antarctic sea ice extent exceeded 20 million square kilometers for the first time since 1979, according to the National Snow and Ice Data Center. The red line shows the average maximum extent from 1979-2014.
Credit: NASA's Scientific Visualization Studio/Cindy Starr



Sea ice surrounding Antarctica reached a new record high extent this year, covering more of the southern oceans than it has since scientists began a long-term satellite record to map sea ice extent in the late 1970s. The upward trend in the Antarctic, however, is only about a third of the magnitude of the rapid loss of sea ice in the Arctic Ocean.
The new Antarctic sea ice record reflects the diversity and complexity of Earth's environments, said NASA researchers. Claire Parkinson, a senior scientist at NASA's Goddard Space Flight Center, has referred to changes in sea ice coverage as a microcosm of global climate change. Just as the temperatures in some regions of the planet are colder than average, even in our warming world, Antarctic sea ice has been increasing and bucking the overall trend of ice loss.

"The planet as a whole is doing what was expected in terms of warming. Sea ice as a whole is decreasing as expected, but just like with global warming, not every location with sea ice will have a downward trend in ice extent," Parkinson said.

Since the late 1970s, the Arctic has lost an average of 20,800 square miles (53,900 square kilometers) of ice a year; the Antarctic has gained an average of 7,300 square miles (18,900 sq km). On Sept. 19 this year, for the first time ever since 1979, Antarctic sea ice extent exceeded 7.72 million square miles (20 million square kilometers), according to the National Snow and Ice Data Center. The ice extent stayed above this benchmark extent for several days. The average maximum extent between 1981 and 2010 was 7.23 million square miles (18.72 million square kilometers).

The single-day maximum extent this year was reached on Sept. 20, according to NSIDC data, when the sea ice covered 7.78 million square miles (20.14 million square kilometers). This year's five-day average maximum was reached on Sept. 22, when sea ice covered 7.76 million square miles (20.11 million square kilometers), according to NSIDC.

A warming climate changes weather patterns, said Walt Meier, a research scientist at Goddard. Sometimes those weather patterns will bring cooler air to some areas. And in the Antarctic, where sea ice circles the continent and covers such a large area, it doesn't take that much additional ice extent to set a new record.
"Part of it is just the geography and geometry. With no northern barrier around the whole perimeter of the ice, the ice can easily expand if conditions are favorable," he said.
Researchers are investigating a number of other possible explanations as well. One clue, Parkinson said, could be found around the Antarctic Peninsula -- a finger of land stretching up toward South America. There, the temperatures are warming, and in the Bellingshausen Sea just to the west of the peninsula the sea ice is shrinking. Beyond the Bellingshausen Sea and past the Amundsen Sea, lies the Ross Sea -- where much of the sea ice growth is occurring.

That suggests that a low-pressure system centered in the Amundsen Sea could be intensifying or becoming more frequent in the area, she said -- changing the wind patterns and circulating warm air over the peninsula, while sweeping cold air from the Antarctic continent over the Ross Sea. This, and other wind and lower atmospheric pattern changes, could be influenced by the ozone hole higher up in the atmosphere -- a possibility that has received scientific attention in the past several years, Parkinson said.

"The winds really play a big role," Meier said. They whip around the continent, constantly pushing the thin ice. And if they change direction or get stronger in a more northward direction, he said, they push the ice further and grow the extent. When researchers measure ice extent, they look for areas of ocean where at least 15 percent is covered by sea ice.

While scientists have observed some stronger-than-normal pressure systems -- which increase winds -- over the last month or so, that element alone is probably not the reason for this year's record extent, Meier said. To better understand this year and the overall increase in Antarctic sea ice, scientists are looking at other possibilities as well.

Melting ice on the edges of the Antarctic continent could be leading to more fresh, just-above-freezing water, which makes refreezing into sea ice easier, Parkinson said. Or changes in water circulation patterns, bringing colder waters up to the surface around the landmass, could help grow more ice.

Snowfall could be a factor as well, Meier said. Snow landing on thin ice can actually push the thin ice below the water, which then allows cold ocean water to seep up through the ice and flood the snow -- leading to a slushy mixture that freezes in the cold atmosphere and adds to the thickness of the ice. This new, thicker ice would be more resilient to melting.

"There hasn't been one explanation yet that I'd say has become a consensus, where people say, 'We've nailed it, this is why it's happening,'" Parkinson said. "Our models are improving, but they're far from perfect. One by one, scientists are figuring out that particular variables are more important than we thought years ago, and one by one those variables are getting incorporated into the models."

For Antarctica, key variables include the atmospheric and oceanic conditions, as well as the effects of an icy land surface, changing atmospheric chemistry, the ozone hole, months of darkness and more.

"Its really not surprising to people in the climate field that not every location on the face of Earth is acting as expected -- it would be amazing if everything did," Parkinson said. "The Antarctic sea ice is one of those areas where things have not gone entirely as expected. So it's natural for scientists to ask, 'OK, this isn't what we expected, now how can we explain it?'"

Story Source:
The above story is based on materials provided by NASA/Goddard Space Flight Center. Note: Materials may be edited for content and length.


NASA/Goddard Space Flight Center. "Antarctic sea ice reaches new record maximum." ScienceDaily. ScienceDaily, 8 October 2014. <www.sciencedaily.com/releases/2014/10/141008122102.htm>.

Penguins Use Their Personalities to Prepare for Climate Change

Birds’ individual personalities may be among the factors that could improve its chances of successfully coping with environmental stressors. Credit: John F. Cockrem, PhD

Date: October 8, 2014

Source: American Physiological Society (APS)

As the global climate continues to change, the ability of many animal species to adapt is being put to the test. Bird populations may be at particular risk. According to the Audubon Society, nearly half of all North American bird species are severely threatened by shifts in climate. The threat reaches beyond North America and could have similar effects on global bird populations.

John Cockrem of the Institute of Veterinary, Animal and Biomedial Sciences at Massey University in New Zealand suggests that a bird's individual personality may be among the factors that could improve its chances of successfully coping with environmental stressors. He studied differences in the level of the stress hormone corticosterone that native little penguins (Eudyptula minor) secreted when exposed to stressful stimulus.

"There is considerable individual variation in corticosterone responses, and a stimulus that initiates a large response in one bird may initiate a small response in another bird," Cockrem wrote. "Corticosterone responses and behavioral responses to environmental stimuli are together determined by individual characteristics called personality. Birds with low corticosterone responses and proactive personalities are likely to be more successful (have greater fitness) in constant or predictable conditions, whilst birds with reactive personalities and high corticosterone responses will be more successful in changing or unpredictable conditions."

These findings may help in predicting the adaptability of bird species as they face a new normal. Cockrem will present the talk "Corticosterone responses and the ability of birds to cope with environmental change" at the American Physiological Society (APS) intersociety meeting "Comparative Approaches to Grand Challenges in Physiology" on October 8, 2014.

 Story Source:
The above story is based on materials provided by American Physiological Society (APS). Note: Materials may be edited for content and length.

American Physiological Society (APS). "Penguins Use Their Personalities to Prepare for Climate Change." ScienceDaily. ScienceDaily, 8 October 2014. <www.sciencedaily.com/releases/2014/10/141008140933.htm>.



Wednesday, October 1, 2014

How dinosaur arms turned into bird wings

Date:
September 30, 2014
Source:
PLOS
Summary:
Although we now appreciate that birds evolved from a branch of the dinosaur family tree, a crucial adaptation for flight has continued to puzzle evolutionary biologists. During the millions of years that elapsed, wrists went from straight to bent and hyperflexible, allowing birds to fold their wings neatly against their bodies when not flying. A resolution to this impasse is now provided by an exciting new study.










(A) Whole-mount alcian blue staining confirms the ulnare is the first carpal formed in avian embryos, distal to the ulna. Thereafter, a distal carpal 3 (referred to as “element x” in previous embryological descriptions) is formed distal to the ulnare, coexisting with it. Finally, the ulnare disappears, whereas dc3 persists.
Credit: J. Botelho et al.; DOI: 
10.1371/journal.pbio.1001957




Although we now appreciate that birds evolved from a branch of the dinosaur family tree, a crucial adaptation for flight has continued to puzzle evolutionary biologists. During the millions of years that elapsed, wrists went from straight to bent and hyperflexible, allowing birds to fold their wings neatly against their bodies when not flying.
How this happened has been the subject of much debate, with substantial disagreement between developmental biologists, who study how the wings of modern birds develop in the growing embryo, and palaeontologists who study the bones of dinosaurs and early birds. A resolution to this impasse is now provided by an exciting new study publishing on September 30 in PLOS Biology.

Underlying this striking evolutionary transformation change is a halving in the number of wrist bones, but developmental biologists and palaeontologists have different names for most of them, and seldom agree on the correspondence between specific dinosaur bones and those of their bird descendants. Indeed, each field has radically different data sources, methods, and research objectives, talking little to each other.

The critical advance made in the new study involved combining these two strands of research. Using an interdisciplinary approach, the lab run by Alexander Vargas at the University of Chile has re-examined fossils stored at several museum collections, while at the same time collecting new developmental data from seven different species of modern birds. Joao Botelho, a Brazilian student in Vargas' lab, developed a revolutionary new technique that allows him to study specific proteins in 3D embryonic skeletons. By combining these data from both fossils and embryos, the research team has made a major step forward in clarifying how the bird wrist evolved.

From early dinosaur ancestors with as many as nine wrist bones, birds have only kept four during the course of evolution, but which of the original bones are they? The identity of each of these bones was debated. For instance, the late Yale professor John Ostrom famously pointed out in the 1970's that the wrists of both birds and bird-like dinosaurs possess a very similar, half-moon shaped bone called the semilunate, and that this bone resulted from the merging of two bones present in dinosaurs. This formed part of Ostrom's then-controversial argument that birds descended from dinosaurs. However, the failure of developmental biologists to confirm this raised doubts that it was the same bone, and even that birds came from dinosaurs.

Now, the new data obtained by the Vargas lab has revealed the first developmental evidence that the bird semilunate was formed by the fusion of the two dinosaur bones. They go on to show that another bone -- the pisiform -- was lost in bird-like dinosaurs, but then re-acquired in the early evolution of birds, probably as an adaptation for flight, where it allows transmission of force on the downstroke while restricting flexibility on the upstroke. Combined, the fossil and developmental data provide a compelling scenario for a rare case of evolutionary reversal.

The study by the Vargas lab also settled the identity of the other two bones of the bird wrist, which were commonly misidentified in both fields. This emphasizes the downsides of not integrating all data sources, and reveals a situation perhaps akin to that of astronomy and experimental physics in the pursuit of cosmology: Together, palaeontology and development can come much closer to telling the whole story of evolution -- this integrative approach resolves previous disparities that have challenged the support for the dinosaur-bird link and reveals previously undetected processes, including loss of bones, fusion of bones, and re-evolution of a transiently lost bone.

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

Journal Reference:
  1. João Francisco Botelho, Luis Ossa-Fuentes, Sergio Soto-Acuña, Daniel Smith-Paredes, Daniel Nuñez-León, Miguel Salinas-Saavedra, Macarena Ruiz-Flores, Alexander O. Vargas. New Developmental Evidence Clarifies the Evolution of Wrist Bones in the Dinosaur–Bird Transition. PLoS Biology, 2014; 12 (9): e1001957 DOI: 10.1371/journal.pbio.1001957


PLOS. "How dinosaur arms turned into bird wings." ScienceDaily. ScienceDaily, 30 September 2014. <www.sciencedaily.com/releases/2014/09/140930144157.htm>.