Thursday, June 24, 2010

Penguin Beaks: Why So Small

Evolution of Bird Bills: Birds Reduce Their 'Heating Bills' in Cold Climates

ScienceDaily (June 24, 2010) — The evolution of bird bills is related to climate according to latest research by the University of Melbourne, Australia and Brock University, Canada.

By examining bill sizes of a diverse range of bird species around the world, researchers have found that birds with larger bills tend to be found in hot environments, whilst birds in colder environments have evolved smaller bills.

The study led by Dr Matt Symonds of the Department of Zoology at the University of Melbourne and Dr Glenn Tattersall of the Department of Biological Sciences at Brock University provides evidence that maintaining body temperature in a bird's natural environment may have shaped the evolution of bird bills.
The size and shape of these distinctive structures are usually explained by their role in feeding and mate attraction. However, previous research shows bird bills have a third, less appreciated function, as organs of heat exchange.

Dr Glenn Tattersall says we know, from our thermal imaging studies that birds like toucans and geese can lose a large amount of their body heat through their bills.

"Unlike humans they don't sweat but can use their bills to help reduce their body temperature if they overheat."
"We then wondered whether this function had evolutionary consequences, and sought to compare bill sizes across a whole range of species," says Dr Tattersall.

The 214 species examined comprised diverse groups including toucans, African barbets and tinkerbirds, Australian parrots, grass finches, Canadian gamebirds, penguins, gulls and terns.

"Across all species, there were strong links between bill length and both latitude, altitude and environmental temperature," Dr Matt Symonds says. "Species that have to deal with colder temperatures have smaller bills."
"This suggests that there is an evolutionary connection between the size of the birds' bills and their role in heat management," he says.

Although it's possible that large bills have evolved to help shed heat loads and prevent overheating in hot climates, we think it's more likely that cold temperatures impose a constraint on the size of bird beaks," Dr Tattersall says.

"It simply might be too much of a liability to carry around a big radiator of heat energy in a cold environment."
The research validates a 133-year-old ecological theory called Allen's rule, which predicts that animal appendages like limbs, ears, and tails are smaller in cold climates in order to minimize heat loss.

Dr Symonds says Allen's rule has never been tested with this large a group of animals and was more anecdotal.

"This is the first rigorous study of its kind to test this theory and to show that bird bills have evolved in this manner."

The paper is published online this week in the journal American Naturalist and will be in the journal's August 2010 edition.

Story Source:
The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of Melbourne.

University of Melbourne. "Evolution of Bird Bills: Birds Reduce Their 'Heating Bills' in Cold Climates." ScienceDaily 24 June 2010. 24 June 2010 <­ /releases/2010/06/100623104428.htm>.

Saturday, June 5, 2010

SF-Based Court Settlement Mean New Protections For Seven Penguin Species

SF-Based Court Settlement Mean New Protections For Seven Penguin Species

penguin1.jpgSeven species of penguins in the Southern Hemisphere will receive protection under the U.S. Endangered Species Act as a result of a settlement reached in federal court in San Francisco.
U.S. District Judge Samuel Conti on Thursday signed off on a settlement reached between the U.S. Interior Department and two conservation groups.
The groups are the Center for Biological Diversity, based in Tucson, Ariz., and the Turtle Island Restoration Network, based in Olema, which sued the government earlier this year.
Catherine Kilduff, a lawyer in the center's San Francisco branch office, said, "Penguins are poster children for the devastating effects of climate change."
Center scientists say that warming oceans, melting sea ice and commercial fishing have wreaked havoc on penguins' food supply.
Turtle Island Restoration Network biologist Todd Stein said, "Finally the government is throwing penguins a lifeline to recovery by protecting them under the Endangered Species Act."
The Center for Biological Diversity's bid to protect the penguins began with the filing of a petition with the Interior Department's Fish and Wildlife Service in 2006.
In December 2008, the service concluded that the seven species should be listed as either threatened or endangered under the Endangered Species Act because of threats from climate change and commercial fishing.
When the service failed to complete the listing process within one year as required by the law, the two groups filed their lawsuit.
The settlement provides that the Fish and Wildlife Service will publish final listing determinations for five of the species by July 30, and for the other two in September and January.
The seven species are African, Humboldt, yellow-eyed, white-flippered, Fiordland crested and erect-crested penguins and a population of the southern rockhopper penguins.
The two groups said they plan to file another lawsuit against the Interior Department for denying listing protection to two other species, the emperor and northern rockhopper penguins.