Sunday, September 29, 2013

The Victory Squawk of the Little Blue Penguin

Apr. 03, 2012
by Kara Rogers
Little Penguin (Eudyptula minor) family exiting burrow, Bruny Island, Tasmania, Australia. Photo by Noodle snacks.

Victory is sweet, so much so that we often feel compelled to rejoice with a cry of triumph. For some animals, that cry not only announces a win to all those within earshot but also serves surprisingly complex social functions. Take, for instance, the call of the victorious little blue penguin (Eudyptula minor), which a recent study in the journal Animal Behavior revealed has a direct effect on the behavior of “social eavesdroppers” -- penguins who, from the safety of their burrows, assess the quality of fighting individuals based solely on their vocalizations.

Male little blue penguins are fierce defenders of their territories and frequently become engaged in flipper-slapping territorial disputes. At the conclusion of a scuffle, the winner celebrates with a so-called triumph display, in which he delivers a victory bray -- a distinctive squawk that according to the new study serves as a sort of warning signal to other males in the colony, potentially mitigating future confrontations for the winner and preventing embarrassing defeats for lesser male challengers.
Little blue penguins, which are the smallest penguins in the world, are social animals that use vocalization during activities such as courtship and foraging and as a way of announcing their arrival at their home burrows. However, while much is known about the various functions of many of the penguins' calls, the social significance of vocalization associated with victory calls had remained unclear.

To assess the impact of triumph brays on the behavior of eavesdropping penguins, the scientists played a recording of a vocal exchange and flipper-slapping fight between territorial males and then played recordings of both the victor's triumph call and the loser's call. They then measured the heart rates of eavesdroppers in response to the sounds using heart monitors hidden in artificial eggs that were placed in the penguins' nests. The team found that eavesdropping males' heart rates increased in response to the victor's call when compared with the loser's call. In addition, in simulated approach experiments in which the loser's or winner's call was played just outside the entrance of an eavesdropper's burrow, the scientists discovered that eavesdropping males challenged the loser's call with vocalizations of their own but fell silent when the triumph call was played.

Triumph displays and other forms of postconflict signaling have been documented in a variety of species, including birds such as the Canada goose (Branta canadensis), the greylag goose (Anser anser), and the bell shrike (Laniarius aethiopicus), as well as animals such as the green frog (Rana clamitans) and an insect known as the Wellington tree weta (Hemideina crassidens). Postconflict signaling in these species appears to function either as a form of advertising, in which the winner's display communicates his dominance to eavesdroppers, or as a form of intimidation, in which the winner's display serves to reduce the chance that the loser will initiate a future challenge. Thus, in many ways, by showing off a little after a victory, these animals are simply establishing their reputation as winners. In other words, they're behaving very much like humans.


Wednesday, September 18, 2013

Ten-Year Project Redraws the Map of Bird Brains

A revised map of the bird brain shows cortical areas organized in columns, as in mammals and humans. (Credit: Image courtesy of Duke University)

Sep. 17, 2013 — Explorers need good maps, which they often end up drawing themselves.

Pursuing their interests in using the brains of birds as a model for the human brain, an international team of researchers led by Duke neuroscientist Erich Jarvis and his collaborators Chun-Chun Chen and Kazuhiro Wada have just completed a mapping of the bird brain based on a 10-year exploration of the tiny cerebrums of eight species of birds.

In a special issue appearing online in the Journal of Comparative Neurology, two papers from the Jarvis group propose a dramatic redrawing of some boundaries and functional areas based on a computational analysis of the activity of 52 genes across 23 areas of the bird brain.

Jarvis, who is a professor of neurobiology at Duke, member of the Duke Institute for Brain Sciences, and a Howard Hughes Medical Institute investigator, said the most important takeaway from the new map is that the brains of all vertebrates, a group that includes birds as well as humans, have some important similarities that can be useful to research.

Most significantly, the new map argues for and supports the existence of columnar organization in the bird brain. "Columnar organization is a rule, rather than an exception found only in mammals," Jarvis said. "One way I visualize this view is that the avian brain is one big, giant gyrus folding around a ventricle space, functioning like what you'd find in the mammalian brain," he said.

To create different patterns of gene expression for the analysis, the birds were exposed to various environmental factors such as darkness or light, silence or bird song, hopping on a treadmill, and in the case of migratory warblers, a magnetic field that stimulated their navigational circuits.

The new map follows up on a 2004 model, proposed by an Avian Brain Nomenclature Consortium, also lead by Jarvis and colleagues, which officially changed a century-old view on the prevailing model that the avian brain contained mostly primitive regions. They argued instead that the avian brain has a cortical-like area and other forebrain regions similar to mammals, but organized differently.

"The change in terminology is small this time, but the change in concept is big," Jarvis said. For this special issue, the of Journal of Comparative Neurology commissioned a commentary by Juan Montiel and Zoltan Molnar, experts in brain evolution, to summarize the large amount of data presented in the studies by the Jarvis group.

One of the major findings is that two populations of cells on either side of a void called the ventricle are actually the same cell types with similar patterns of gene expression. Earlier investigators had thought of the ventricle as a physical barrier separating cell types, but in development studies led by Jarvis' post doctoral fellow Chun-chun Chen, the Duke researchers showed how dividing cells spread in a sheet and flow around the ventricle as they multiply.

The new map simplifies the bird cortex, called pallium, from seven populations of cells down to four major populations. Humans have five populations of cells in six layers.

Part of this refinement is simply that the tools are getting better, says Harvey Karten, a professor of neurosciences at the University of California-San Diego who proposed a dramatic re-thinking of bird cortical organization in the late 1960s. The best tools in that era were microscopes, specific cell stains and electrophysiology. Karten and colleagues are authors of a fourth paper in the special issue which announces a database of gene expression profiles of the avian brain containing some of the data that the Jarvis group used.

Jarvis said having a more specific map is necessary for properly sampling cell populations for gene expression analysis to do even more functional analysis of how the brain operates. As a next step, his team is considering doing an even more detailed bird map with "several hundred" genes rather than the 52 used to make this map.

Jarvis and colleagues are working now on a similar mapping of the crocodile brain with the ultimate goal of being able to say something about how dinosaur brains were organized, since both birds and crocs are descended from them. At a Society for Neuroscience conference in November, they'll be presenting some early findings from that project.

Though the specifics of this newest map may only be of interest within the bird research community, Jarvis said, it builds the awareness that birds can be a useful model for many questions about the human brain.

"Where does the mammalian brain come from?" Karten asks. "And what's the origin of these structures at the cellular and molecular level?" Some neuroscientists have argued that the mammalian cortex -- the one we have -- is something apart from the brains of other vertebrates. Jarvis and Karten now think vertebrate brains have more commonalities than differences.

That awareness is making birds an ever more useful model for questions about the human brain. "There are very few animal models where you can learn -- at the molecular level -- what's going on in vocal learning," Karten said. Birds are also being used as models for research on Parkinson's, Huntington's, deafness and other degenerative conditions in humans.

The work was supported by grants from Human Frontiers in Science Program, The National Science Foundation, NIMH (R01-MH62803), NIDCD (R01-DC007218), NIH ARRA Supplement 3DP10D000448-04S1 and the Howard Hughes Medical Institute.

Story Source:
The above story is based on materials provided by Duke University.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal References:
  1. Erich D. Jarvis, Jing Yu, Miriam V. Rivas, Haruhito Horita, Gesa Feenders, Osceola Whitney, Syrus Jarvis, Electra R. Jarvis, Lubica Kubikova, Ana E. P. Puck, Connie Siang-Bakshi, Suzanne Martin, Michael McElroy, Erina Hara, Jason Howard, Henrik Mouritsen, Chun-Chun Chen, Kazuhiro Wada. A global view of the functional molecular organization of the avian cerebrum: Mirror images and functional columns. Journal of Comparative Neurology, 2013; DOI: 10.1002/cne.23404
  2. Chun-Chun Chen, Candace M. Winkler, Andreas R. Pfenning, Erich D. Jarvis. Molecular profiling of the developing avian telencephalon: regional timing and brain subdivision continuities. Journal of Comparative Neurology, 2013; DOI: 10.1002/cne.23406

Duke University (2013, September 17). Ten-year project redraws the map of bird brains. ScienceDaily. Retrieved September 18, 2013, from­ /releases/2013/09/130917093924.htm

How Birds Got Their Wings: Fossil Data Show Scaling of Limbs Altered as Birds Originated from Dinosaurs

Archaeopteryx lithographica, specimen displayed at the Museum für Naturkunde in Berlin. Believed to be a transitional species between theropod dinosaurs and birds, Archaeopteryx had longer forelimbs and shorter hind limbs than its ancestors. (Credit: By H. Raab (User:Vesta) (Own work) [CC-BY-SA-3.0 or GFDL], via Wikimedia Commons)

Sep. 17, 2013 — Birds originated from a group of small, meat-eating theropod dinosaurs called maniraptorans sometime around 150 million years ago. Recent findings from around the world show that many maniraptorans were very bird-like, with feathers, hollow bones, small body sizes and high metabolic rates.

But the question remains, at what point did forelimbs evolve into wings -- making it possible to fly?
McGill University professor Hans Larsson and a former graduate student, Alexander Dececchi, set out to answer that question by examining fossil data, greatly expanded in recent years, from the period marking the origin of birds.

In a study published in the September issue of Evolution, Larsson and Dececchi find that throughout most of the history of carnivorous dinosaurs, limb lengths showed a relatively stable scaling relationship to body size. This is despite a 5000-fold difference in mass between Tyrannosaurus rex and the smallest feathered theropods from China. This limb scaling changed, however, at the origin of birds, when both the forelimbs and hind limbs underwent a dramatic decoupling from body size. This change may have been critical in allowing early birds to evolve flight, and then to exploit the forest canopy, the authors conclude.

As forelimbs lengthened, they became long enough to serve as an airfoil, allowing for the evolution of powered flight. When coupled with the shrinking of the hind limbs, this helped refine flight control and efficiency in early birds. Shorter legs would have aided in reducing drag during flight -- the reason modern birds tuck their legs as they fly -- and also in perching and moving about on small branches in trees. This combination of better wings with more compact legs would have been critical for the survival of birds in a time when another group of flying reptiles, the pterosaurs, dominated the skies and competed for food.

"Our findings suggest that birds underwent an abrupt change in their developmental mechanisms, such that their forelimbs and hind limbs became subject to different length controls," says Larsson, Canada Research Chair in Macroevolution at McGill's Redpath Museum. Deviations from the rules of how an animal's limbs scale with changes in body size -- another example is the relatively long legs and short arms of humans -- usually indicate some major shift in function or behaviour. "This decoupling may be fundamental to the success of birds, the most diverse class of land vertebrates on Earth today."

"The origin of birds and powered flight is a classic major evolutionary transition," says Dececchi, now a postdoctoral researcher at the University of South Dakota. "Our findings suggest that the limb lengths of birds had to be dissociated from general body size before they could radiate so successfully. It may be that this fact is what allowed them to become more than just another lineage of maniraptorans and led them to expand to the wide range of limb shapes and sizes present in today's birds."

"This work, coupled with our previous findings that the ancestors of birds were not tree dwellers, does much to illuminate the ecology of bird antecedents." says Dr. Dececchi. "Knowing where birds came from, and how they got to where they are now, is crucial for understanding how the modern world came to look the way it is."

Funding for the research was provided by the Fonds de recherche du Québec -- Nature et technologies, the Canada Research Chairs program, and the National Sciences and Engineering Research Council of Canada.

Story Source:
The above story is based on materials provided by McGill University.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:
  1. T. Alexander Dececchi, Hans C. E. Larsson. Body and Limb Size Dissociation at the Origin of Birds: Uncoupling Allometric Constraints Across a Macroevolutionary Transition. Evolution, 2013; 67 (9): 2741 DOI: 10.1111/evo.12150

McGill University (2013, September 17). How birds got their wings: Fossil data show scaling of limbs altered as birds originated from dinosaurs. ScienceDaily. Retrieved September 18, 2013, from­ /releases/2013/09/130917123613.htm

Sunday, September 8, 2013

Worldwide Researchers Flock to Penguin Meeting

Originally published on Fri September 6, 2013


This is SCIENCE FRIDAY. I'm Ira Flatow. Just about everybody loves penguins, right? They're funny on land. They're amazing underwater, and they're very photogenic, so they show up in lots of ads and movies. But beyond the screen, prospects for the birds are not entirely good. This week, over 200 researches from around the world met in the U.K. to talk penguins, from the prospects of conservation of species to how penguins are able to stay under water so long, to the properties of penguin poop.

Joining me now to talk about it is Peter Barham. He's a professional teaching fellow in physics at the University of Bristol. He's also the chair of the organizing committee for the Eighth International Penguin Conference, which wrapped up today. Welcome to SCIENCE FRIDAY.

PETER BARHAM: Good afternoon, I think it must be, Ira.

FLATOW: Thank you. First let me ask you: What's a physicist doing studying penguins?

BARHAM: Oh, physicists, of course, we turn our hands to anything. But I have had, through my wife, an obsession with penguins for quite some time. And a while back, must be - it was about 15, 16 years ago now, I went to the Third International Penguin Conference for fun and discovered that there were things to with tagging and marking and following penguins which a physicist's skills were helpful for, and got involved then, and it's since become a major part of my research career.

FLATOW: Yeah. You know, we see penguins in so many ads on TV and the movies, cute little fellows. We don't think of them as endangered at all, but they are, according to...

BARHAM: They are very much endangered, yes. There are 18 or maybe 19 species of penguin. It depends on how you do the genetics. and of those, all but three are listed on the IUCN red listed as being at least threatened, and three - no, four now are listed as being actually endangered. And of those, I would be surprised if any are still around at the end of this century.

FLATOW: Wow. And where is the endangerment coming from?

BARHAM: It's a mixture of causes. Principally, it is down to the inability of the penguins to find sufficient food in the localities where they're situated. Penguins, because when they're breeding and their raising young, have to go return to the colony where the young are, they can only swim for - depending on the species - one day or maybe three or four days before they have to return with food for the young.

And if there is no easily accessible food within that distance that they can find in the time, then they can't breed. So that's one of the major causes. Those, of course, are caused by the changing locations of fish because of a global change in ocean currents and the rising temperatures in the Antarctic of melting the ice, and also by the fact of where the fish are in large quantities is also where our fishing vessels are. And so there's competition with fisheries.

FLATOW: Wow. Is there some tool that the penguin research community really needs now?

BARHAM: There are lots of tools we need, and we've invested a lot of effort into managing to find great deal of information by remote sensing technologies. We had quite a lot of talks at the conference on using satellite imagery to locate penguin conferences(ph). But we still don't have a good technology for really understanding what they're doing on the longer trips away from the colonies between breeding seasons, when, actually, we know now that how well fed they are at the onset of breeding, then it has a great influence on how they breed. There's no technology which will last that long.

FLATOW: Because of the climate down there is so harsh.

BARHAM: People think of penguins coming from cold places. That's a fallacy. Penguins do breed all over the Southern Hemisphere, anywhere there is cold water. So there are penguins breeding in the Galapagos Islands - not many left, but they're there. And there actually are a few pairs of penguins that breed in the Galapagos Islands just north of the equator. Very few of those, probably three or four pairs in total.

But you'll find penguins breeding with their nest sites in the Atacama Desert in the west coast of Chile and Peru. You'll find penguins in Southern Africa. That's where I work, in around the Cape Town area, where the temperatures can easily reach 30 degrees. So the idea that penguins are limited to Antarctica is not true. And, in fact, the most endangered species are the temperate species, the species that are not in Antarctica.

FLATOW: So what's the course of action? How can - first, I guess you would have to get the public to realize how endangered they are.

BARHAM: That's a really key point: getting people involved and on all sides. And then the sort of measures you have to employ are things like habitat reconstruction, because we have effectively destroyed nearly all the penguin habitats in the temperate regions, because penguins live in sea bird colonies. Sea birds poop, and sea bird poop is guano, which is a fantastic fertilizer, and it's all being taken away. So they haven't got anywhere to nest any longer. So we have to put out artificial nests for them, and determining what the best sort of nest is.

That's one thing we can do. Other things we can do is try to influence fishery policy in those areas where penguins live, to sway the policymakers to ensure that the fishermen are not operating the same areas in direct competition with the penguins. And we know where the penguins - well, we have a good idea where the penguins are foraging, and we actually put tracking devices on them so we know where they are, and we can get some information that way.

FLATOW: Well, there are all kinds of treaties for fishing all kinds of different things in the oceans. There's nothing for penguins yet?

BARHAM: Well, there are no local treaties. These treaties that exist are largely global scale. So whilst there are maximum allowable catches in certain areas, they normally do not give escapement in the local area under penguin colony. So penguin colonies can be on a small island, or it may just be a 40-mile area around that island that's important, whereas the fishing (unintelligible) vast tracts of the oceans.

FLATOW: Right. You said one of the real problems you have is collecting data from these penguins. How could you - what kind of technology could...

BARHAM: Well, technology is fairly getting better. But what we need at the moment - and this came up quite a lot in our discussions - is the things we can't found out about are in detail what the penguins are doing when they are fishing. We can put GPS loggers, the time-depth recorders, so we can see when they're diving, how deep they're diving. But we can't really tell when they're eating and what they're eating.

And then if we do that, typically, those devices will only last with the battery power we have for up to a few weeks. Or you can put them on - they switch on. So we don't know what happens through - most penguin species will spend about three or four months away feeding up between breeding seasons, and that is a crucial part. We don't know where they're doing it. So we can't say to the fishing industries please don't fish there at that time of year, because we don't know where to say.

FLATOW: And you don't have any money to study it, I'll bet?

BARHAM: The sort of money you're talking about for those sorts of things would be quite high, but, you know, a -I mean, a typical tracking device which you'd put on at that stage would be lost because the bird would molt and it would leave the device behind. So it has to be a satellite that dumps the information back to the satellites. Those things work out at around about 3 to $5,000 each. You would need to take maybe several hundred tracts to get any real data. So you're looking at several hundreds of thousands of dollars to get one season's worth of data. Not cheap.

FLATOW: That's not really a lot of money, either, in, you know, when you think - compared to other things.

BARHAM: Well, it's not a lot of money, but it's not the sort of money that gets given out for these sorts of conservation projects. They're not sexy. They don't attract high sums of money from funders, by and large.

FLATOW: Yeah. You need a TV show.

BARHAM: That's a good thought, yes. The TV shows tend to be on the nice, cuddly side of penguins. It doesn't mention, oh by the way, they're on the way down. The other thing you said, by the way, penguins being cute. I can assure you they are not cute. They are vicious things, generally speaking. They hurt. They bite and scratch and everything else. So, yeah.

FLATOW: Yeah. Years ago, I had a few Emperor Penguins friendly to me when I was in Antarctica, but...

BARHAM: Yeah, I mean, Emperor Penguins are so unaccustomed to people that they will generally wander up to you and ignore you. But if you were, however, to want to put a tracking device on one, you would need to constrain it. You would need to hold it, and then you'd probably feel how powerful its flippers are. Species I work with, the African Penguin, they have - a best description from a colleague of mine was: They're a pair of razorblades on legs.


FLATOW: Wow. Now I know why you've fallen in love with penguins. It's fascinating. Listen, when I was in Antarctica, I fell in love with them, too, down there. So I wish you good luck. I wish now you get the amount of money you need to do your research. Money's tight. It doesn't seem like a lot of money. Good luck to you.

BARHAM: OK. Thank you very much.

FLATOW: Peter Barham is a professional teaching fellow in physics at the University of Bristol and chair of the organizing committee for the Eighth International Penguin Conference, which took place this week in Bristol, U.K. Transcript provided by NPR.


Saturday, September 7, 2013

Novel Method to Identify Suitable New Homes for Animals Under Threat from Climate Change

Emperor penguins. (Credit: Copyright Dr. Paul Ponganis, National Science Foundation)

Sep. 5, 2013 — Scientists at the Zoological Society of London (ZSL) have devised a novel method to identify suitable new homes for animals under threat from climate change.

Conservation scientists used their knowledge on species ecology to create habitat suitability maps and correctly identify sites that will remain viable in the future regardless of changing climate. However, the key for success is to understand, and account for, the link between variation in species population size, climate and how the climate may change.

Almost half of all bird and amphibian species are believed to be highly vulnerable to extinction from climate change. Species in extreme or rare habitats such as the emperor penguin in the Antarctic and American pika in the USA have already experienced drastic declines in populations due to the impact of climate change on their home.

As climate changes, many species will need to move to a different location in order to survive. For species that aren't able to do this naturally, the only chance of survival is a helping hand through the use of translocations.

The research is published today (6 September) in the Journal of Applied Ecology.

Dr Nathalie Pettorelli, ZSL's climate change coordinator and senior author on the paper, says: "Climate change poses a worrying threat to many animals, and relocating vulnerable species to new and more suitable habitats may be the only way to protect them. However, this is an extreme conservation action, which needs to be thoroughly justified, and requires clear guidance on where threatened populations should be moved. Our research shows how these key requirements can be met."

The team used the hihi bird as an example because of the conservation success which came after efforts put into its relocation since the 1980s. Yet, despite large investments into its protection, climate change is now posing a significant threat to its future survival.

Dr Alienor Chauvenet, lead author of the study, says: "All current hihi populations are surrounded by either a large stretch of water or unsuitable habitat such as farmland or cities with plenty of non-native predators. This isolation makes it very perilous for them to move and individuals attempting to relocate naturally are unlikely to survive.

"Our work shows that assisted colonisation may be the only way to guarantee the survival of this unique species under climate change," Dr Chauvenet added.

Translocations will continue to be an important part of conservation as climate changes. ZSL's novel method shows how these interventions can be planned to be successful even under the influence of a changing environment. The method can be applied to any species threatened by climate change, and is likely to contribute to the success of future translocations.

Story Source:
The above story is based on materials provided by Zoological Society of London, via EurekAlert!, a service of AAAS.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Zoological Society of London (2013, September 5). Novel method to identify suitable new homes for animals under threat from climate change. ScienceDaily. Retrieved September 7, 2013, from­ /releases/2013/09/130905203018.htm

Tuesday, September 3, 2013

How Emperor Penguins stay underwater for 27 minutes

New research has revealed how the Emperor Penguin is able to dive to depths of over 500m and stay under water for up to 27 minutes – deeper and longer than any of its fellow avian species.
Researchers from the University of California will be presenting their new findings at the International Penguin Conference (IPC) which begins in Bristol today [02 September].

It's the first time the conference has been held in Europe, with 200 delegates from 30 countries sharing their latest research and knowledge at the University of Bristol and Bristol Zoo Gardens between 2 and 6 September.

Alexandra Wright and Dr Paul Ponganis investigated the heart rate response of Emperor Penguins as they made foraging trips to sea from the Cape Washington Colony in Antarctica.

Emperor Penguins also have unusually structured hemoglobin to allow it to function at low oxygen levels, solid bones to reduce barotrauma - physical damage to body tissues caused by a difference in pressure between a gas space inside, or in contact with the body, and the surrounding fluid, and the ability to reduce metabolism and to shut down non-essential organ functions.

The profound decline in heart rate - known as bradycardia – decreases oxygen consumption, conserves the respiratory and blood oxygen stores, and isolates muscle, which must rely instead on its own oxygen store which is bound to the muscle protein, myoglobin.

Although this heart rate response contrasts with other birds and terrestrial mammals, it is similar to the dive response of marine mammals.

Archbishop Desmond Tutu recorded a special video message to launch the event, which will see delegates sample papers on everything from “monitoring global penguin population change” to “the power of poo.”

The public are also invited to get involved thanks to two public events this week. Bristol University graduate Elizabeth White, one of the directors of the popular Frozen Planet series, will be part of a free panel discussion entitled ‘Penguins on Film’ being held in the Wills Memorial Building on Wednesday, 4 September.

Footage from the BBC Natural History Unit, captured by a crew who spent four months with a penguin colony in the Antarctica, will show how Adelie penguins steal stones from its neighbours’ nests to elevate and protect their eggs from run-off when the Antarctic ice melts.

Captivating slow motion footage will illustrate that penguins can ‘fly’, showing how Emperor penguins – the largest of all penguins, reaching up to 120cm tall – manage to get airborne by swimming at speed towards the surface of the water and landing back on the ice.
  • For further details about the ‘Penguins on Film’ event, please see here. It’s free but booking is required.
There will also be an opportunity to learn more about the African penguin at Bristol Zoo Gardens on Saturday, 7 September, with activities for all the family and the chance to meet scientists and conservationists who work with African penguins in South Africa and Namibia.