Birds have more than one way of adapting to extreme temperatures

    By Kathleen Berger, Executive Producer for Science and Technology

    Photographing birds around the world is not just a hobby for Justin Baldwin.  Baldwin is PhD candidate in the Ecology & Evolutionary Biology program at Washington University in St. Louis. Baldwin’s enthusiasm for birds and photography is helping researchers around the world.

    “I contribute all these images to platforms that allow researchers to discover new things about how they (birds) live, why they’re so weird, why we have different communities of them in different places, and how they’ve adapted to the natural world, to their habitats that they’re founded.”

    Baldwin isn’t just standing back letting other scientists do all the research.  His work, in fact, took flight reaching biologists around the world! The study involved a collaboration between Washington University in St. Louis and The University of Texas at Austin. It reveals clues about the relationship between temperatures and changes in the size of warm-blooded animals and their body parts.

    “We just published a paper, I’m first author and corresponding author of a very collaborative effort. It’s a study where we examined how birds have evolved to deal with extreme temperatures, both hot and cold, over really long timescales. So, starting from the dinosaurs up until today.”

    The new research offers important clues about the way that animals, particularly birds, have adapted to changes in ambient temperatures.

    “All birds have been getting smaller, as the climate has warmed, and their appendages have been getting a little bit longer. Birds are going to be changing their sizes, they’re going to be changing their shapes,” said Baldwin. “And what our study did was essentially confirmed that these processes are occurring across 7,000 of the world’s 10,000 bird species at a longer timescale, and at the level of bird families.”

    Two widely accepted “rules” in biology — Allen’s and Bergmann’s rules — indicate that as local temperatures change, animals are likely to adjust their heat transfer capabilities by changing the size of their bodies or the length of their extremities. But Baldwin and his team’s research is first to show how families of birds are not just changing only their body size or only their bill size.

    “These two long, well-known modes of adaptation – the change in body size and the change in bill size – have been known for about 175 years, and biologists have been bickering with each other for the last 175 years about which is right,” said Baldwin. “But if you actually just look at both at the same time, they do both! They’re not changing only the body size, they’re not changing only the bill size, they’re doing a little bit of both at the same time.”

    “There are two complimentary pathways that birds can choose from, as they meet the challenges of extreme temperatures,” explained Baldwin. “Our study is unique in the sense that when you consider how birds have been adapting via these two pathways at the same time, most families of birds appear to do a little bit of both kinds of changes.”