(ORDO NEWS) — For the first time, scientists have linked the cognitive abilities of birds to changes in their bodies in response to global warming.
It turned out that species with a larger brain decrease in size more slowly than relatives with a small brain, and this allows them to more effectively adapt to new conditions.
The body size of many species of migratory birds has decreased markedly over the past 40 years, the reason for this was global warming.Now, scientists at Washington University in St. Louis have found that birds with large brains relative to body size are less likely to experience this trend.
The study, published in the journal Ecology Letters, shows for the first time a direct relationship between the cognitive abilities of birds and changes in their size caused by climate warming.
Scientists analyzed information about approximately 70,000 birds that died in a collision with buildings in Chicago from 1978 to 2016.
This extensive dataset has been supplemented with new brain volume measurements and lifespan information for 49 North American migratory species.As it turned out, in birds with a large brain, the body size decreased three times less than in counterparts with a small brain.
Relative brain size is often considered a proxy for cognitive ability. Such a hypothesis is not applicable to many animals, but it has been proven for birds.
Birds with large brains are better learners, have better memories and longer lifespans, and their populations tend to be more stable. In the case of global warming, high cognitive abilities allow animals to look for more suitable habitats.
Changes in body size are observed in a huge number of species, and scientists consider this a universal adaptation to global warming.
The heat leads to heat stress, and the smaller size allows the body to cool more efficiently. This hypothesis is consistent with observations that birds living in warmer parts of their ranges tend to be smaller than those living in colder regions.
However, size reduction requires new adaptations, as it makes birds more vulnerable to predators and reduces their competitiveness. Thus, a large brain and high cognitive abilities make it possible to adapt to a warming climate through behavioral changes. This alternative is not available to small-brained birds forced to shrink in size.
The results of the study are also important for the conservation of birds. Since the 1970s, their numbers have fallen by three billion in North America (about 33%).
According to scientists, birds with small brains can suffer much more from the effects of global warming, and this must be taken into account when developing conservation strategies.
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