Climate change is causing birds to become smaller – study

PanARMENIAN.Net - For almost four decades, ornithologist David Willard has collected and measured Chicago's dead bird population. His data shows a concerning trend: North America's migratory birds have been shrinking over time.

According to a study published in the journal Ecology Letters, birds' legs are getting shorter, their wings are getting longer and they've been losing weight. Willard and his colleagues say climate change is to blame, CBS reports.

The scientists believe that as temperatures rise, the birds are shrinking to adapt. Animals that live in cold climates tend to be larger than animals that live in warmer areas, because they use the extra weight to stay warm.

"As the breeding grounds of these birds are getting warmer, it may be advantageous to be smaller," Willard said.

Willard has been studying the Windy City's birds in a Field Museum lab since 1978. All of the birds he and volunteers have collected died after flying into buildings. Hundreds of millions of birds are estimated to die in building collisions every year.