Global warming may cause birds to shrink.

ISLAMABAD -- As the planet continues to warm, researchers are increasingly pointing out the ways in which global warming will affect our health and that of the species around us. For example, some species of fungi that are resistant to existing treatments may be on the rise as a result of global warming, one study showed. Also, several species of fish may become more toxic as a result of warming waters, and malaria may spread to an unprecedented extent.

Now, new research appearing in the journal Ecology Letters explores the ways in which birds may have been affected by rising global temperatures. Benjamin Winger, Ph.D., of the Department of Ecology and Evolutionary Biology and the Museum of Zoology at the University of Michigan, in Ann Arbour, is the senior author of the new study. Studying over 70,000 birds As Winger and colleagues explain in their paper, existing research supports the idea that increasing global temperatures will cause reductions in animals' sizes. In fact, a premise in ecogeography known as Bergmann's rule states that animals tend to be smaller in warmer parts of the world, compared with their counterparts of the same species that live in colder climates.

To determine whether this effect is already noticeable in birds as a result of global warming, the researchers analysed 70,716 dead migratory birds of 52 North American species. The researchers obtained these birds from the Field Museum of Natural History, in Chicago, IL, which had been collecting them from building collisions since 1978. So, Winger and the team were able to examine changes in the birds' body sizes over a 38-year period ending in 2016. The scientists measured and...