Global heating causes birds to become smaller

BIRDS are getting smaller due to climate change, scientists have claimed after examining the bodies of those that collided with skyscrapers over four decades.

The study which looked at 70,000 birds which had died after collisions with highrise buildings in Chicago found that birds have been decreasing in size while their wings have become longer.

Scientists from the University of Michigan said this was due to global warming, adding evidence to the longheld theory that climate change is impacting the size of creatures on Earth.

The study, published today in the journal, Ecology Letters, found that between 1978 and 2016 the body size of 49 of the 52 species studied significantly decreased.

During the same period the wing length had increased significantly in 40 species. The scientists claimed this was in order to adjust for the changing weight of the birds.

Study leader, Assistant Professor Brian Weeks, said: “We had good reason to expect that increasing temperatures would lead to reductions in body size, based on previous studies.

“The thing that was shocking was how consistent it was. I was incredibly surprised that all of these species are responding in such similar ways.”

The study is the largest specimen-based analysis of body size in response to global warming ever conducted.

“Periods of rapid warming are followed really closely by periods of decline in body size, and vice versa,” said Prof Weeks.”

The research was completed in conjunction with the Field Museum in Chicago where ornithologists had collected tens of thousands of dead birds from the local area.

Dave Willard, the collection manager who assembled more than 100,000 dead birds from the city’s streets, killed while migrating between Canada and South America in the spring and autumn, added: “The results from this study highlight how essential longterm data sets are for identifying and analysing trends caused by changes in our environment.”

Chicago is situated on a major migration path.