Birds are shapeshifting in response to climate change, researchers report

Sept. 7 (UPI) -- Animals are changing their bodies to adapt to rising global temperatures. Among shape-shifters, birds are leading the charge.

According to a new survey, published Tuesday in the journal Trends in Ecology and Evolution, bird species are altering their physiology -- growing bigger beaks or longer legs -- in response to climate change.

In the news, climate change is often framed as a problem for humans. Climate change is indeed caused by humans, but it is just as much a problem for animals.

"It's high time we recognized that animals also have to adapt to these changes, but this is occurring over a far shorter timescale than would have occurred through most of evolutionary time," lead study author Sara Ryding said in a press release.

"The climate change that we have created is heaping a whole lot of pressure on them, and while some species will adapt, others will not," said Ryding, a bird researcher at Deakin University in Australia.

Like so many of climate change's consequences, the precise impact of rising temperatures or shifting weather patterns on any one animal species is hard to detect. According to Ryding, there are likely a range of factors influencing changes in animal bodies.

But the global nature of shapeshifting suggests climate change as the primary driver. Body changes among species all over the globe -- birds from a wide range of distinct ecosystems -- correspond with rising temperatures.

For example, several parrot species in Australia have increased their beak size between 4% and 10% since 1871. Beak size increases among the parrots corresponds with rises in average summer temperatures.

Birds aren't getting bigger exclusively. Separate studies have shown that migrating birds have been steadily shrinking as global temperatures rise.

It's not the first time climate change has driven physiological and evolutionary changes among bird species. Previous research suggests a period of widespread cooling trends that began 91 million years ago led to rapid diversification among the earliest modern birds.

Though shapeshifting has been most evident among birds, researchers have also measured body changes among mammals. Wood mice have lengthened their tails as temperatures rise, as have masked shrews.

"The increases in appendage size we see so far are quite small -- less than 10% -- so the changes are unlikely to be immediately noticeable," said Ryding. "However, prominent appendages such as ears are predicted to increase -- so we might end up with a live-action Dumbo in the not-so-distant future."

In a followup study, Ryding plans to analyze body size changes among Australian bird species by 3D-scanning specimens from a variety of science museums.

"Shapeshifting does not mean that animals are coping with climate change and that all is 'fine,'" says Ryding. "It just means they are evolving to survive it -- but we're not sure what the other ecological consequences of these changes are, or indeed that all species are capable of changing and surviving."