Figure 1: A bay-breasted warbler with a relatively small brain size
Source Credit: CNN (LINK)
Climate change affects every bit of society. Animals are not an exception. They migrate to higher elevations or adapt to crises by changing their body sizes and shapes. For instance, their beaks, legs, and ears become larger to regulate body temperature better. Another phenotypic response is their decreasing body size. Although its reason is not entirely clear, it can be presumed that it is because of its advantage in dissipating heat; there is an observation that highlights how birds living in warmer areas are smaller than those living in the range of low temperature. Living on a warming planet, it is critical to find ways of losing heat.
However, there are fatal consequences to altering their body size. Birds have a higher risk of getting hunted by predators and failing to obtain necessary resources in competition with other species. So is changing body size advantageous? Are there any alternatives? Fortunately, researchers from Washington University in St.Louis have found an explanation.
In Chicago, thousands of birds die when they collide with skyscrapers during their spring and fall migrations. However, their deaths have been recorded and collected by the city’s museum, and by analyzing 70,000 birds between 1978 and 2016, researchers were able to observe their physical changes. According to their new study, not all bird species develop smaller body sizes. Justin Baldwin, an author of a news release “Brainy birds may fare better under climate change” stated, “As temperatures warm, body sizes are decreasing. But larger-brained species are declining less strongly than small-brained species.” For example, Parulidae in Figure 1 tend to shrink more due to their small brains.
Baldwin’s article demonstrates that a bird's brain size correlates with its change in body size. If so, how are big-brained birds adapting differently to climate change? "In this case, a bigger-brained species of bird might be able to reduce its exposure to warming temperatures by seeking out microhabitats with cooler temperatures, for example," Baldwin said. This is possible because big-brained birds have better learning abilities. Although this is not true for many animals, he says that for birds, "relative brain size correlates with increased learning ability, increased memory, longer lifespans, and more stable population dynamics."
However, other explanations do exist. For example, some argue that since some species have longer lives, evolution might be slower. Also, even if the research explained above is true, it does not mean brainy birds are not affected by climate change at all. But as Carlos Botero, assistant professor of biology at Washington University, said, the significance is that “we can already see that climate change is having a disproportionate effect on species that have less capacity to deal with environmental change through their behavior."
Sunmin Lee
Q&A:
Hannah: You mentioned in your article that birds with small brains tend to decrease in body size more. Why does this correlation exist? What does the size of the brain have to do with surviving climate change and decreasing body size?
-As I mentioned in my article, big-brained birds have better learning abilities. Therefore, they can find an alternative to changing their body size.
John: What adaptations other than decreasing body size do you expect to occur as the effects of global warming continue to ravage Earth’s environments and its avian inhabitants?
-As birds with big brains do currently, birds may seek other habits with cooler temperatures or find places in other altitudes.
Wooseok: Considering how bird species with larger brain sizes are less vulnerable to climate change according to the article, can it be assumed that there will be an increase in the average brain size of bird species in the future?
-Presumably, yes. Since small brained birds fail to find solutions to adapting to climate change other than decreasing their body sizes, their population size will become smaller, resulting in an increase in the average brain size of bird species.
Works Cited:
Doug Johnson - Feb 14, 2022 6:45 pm UTC. “Weathering Climate Change May Be Easier for Birds with Big Brains.” Ars Technica, 14 Feb. 2022, arstechnica.com/science/2022/02/weathering-climate-change-may-be-easier-for-birds-with-big-brains/.
Hunt, Katie. “How Birds Are Adapting to Climate Crisis.” CNN, Cable News Network, 11 Feb. 2022, edition.cnn.com/2022/02/11/americas/birds-brains-climate-change-scn/index.html#:~:text=Larger body size helps animals,migration, researchers have also found.
WUSTLnews. “Brainy Birds May Fare Better under Climate Change.” EurekAlert!, www.eurekalert.org/news-releases/942288.
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