Giving Compass' Take:

• Jim Erickson explains how climate change is causing migratory birds in North America to shrink while their wings grow longer. 

• How can funders help to clarify the consequences of climate change on wildlife? How can these effects be mitigated? 

• Learn how nature can help can combat climate change. 

In what appears to be a response to climate change, migratory birds in North America have been shrinking, report researchers.

Their wings have also gotten a bit longer over the past four decades.

The study involves a dataset of some 70,000 North American migratory birds from 52 species that died when they collided with buildings in Chicago.

Since 1978, Field Museum personnel and volunteers have retrieved dead birds that collided with Chicago buildings during spring and fall migrations. They take multiple body measurements of each specimen.

The research team analyzed this remarkably detailed dataset to look for trends in body size and shape. The biologists found that, from 1978 through 2016, body size decreased in all 52 species, with statistically significant declines in 49 species.

Over the same period, wing length increased significantly in 40 species. The findings appear in the journal Ecology Letters.

“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,” says study lead author Brian Weeks, an assistant professor at the University of Michigan School for Environment and Sustainability.

The new study is the largest specimen-based analysis of body-size responses to recent warming, and it shows the most consistent large-scale responses for a diverse group of birds, Weeks says.

Read the full article about climate changes and migratory birds by Jim Erickson at Futurity.