Environmental Progress Seen Through Bird Specimen Collections


Grasshopper sparrow specimens from 1907, top, and 1996. Credit Carl Fuldner and Shane DuBay

A fascinating story appears in the Science section of the New York Times this week. It is a reminder of the progress made over the last century in cleaning up the air in North America. Birds are key to the evidential trail in telling the story. The title is one of the most unappealing we have seen in ages, but science is not all sweetness and light:

The Dirty Secrets Saved in Dead Birds’ Feathers

Tucked away in the drawers of natural history museums across America’s Rust Belt, thousands of dead birds carry dirty secrets from America’s polluted past.

The specimens that were put away around the start of the 20th century are far grimier than the ones from more recent decades. And now, climate scientists and historians can thank museum curators for not having tidied them up before storing them.

That’s because the soot preserved on their feathers contains missing pixels in a picture of urban air pollution over 135 years, according to a study published Monday in Proceedings of the Natural Academy of Sciences. Their feathers reveal historical air quality in Pennsylvania, Ohio, Indiana, Michigan, Illinois and Wisconsin, dating back more than 70 years before federal monitoring standards were established.

When two graduate students at the University of Chicago measured black carbon clinging to the chests and bellies of more than 1,300 birds in collections at museums in America’s Rust Belt, they found that the dirt on their plumage contained a record of America’s coal use over time.

Between 1880 and 2015, the filth on their feathers undulated with social changes and environmental policy. The dirtiest birds flew through the skies just before 1910, at the height of industrialization. But during the Great Depression and after the middle of the 20th century, birds soared with brighter feathers as people burned less coal and home heating switched from fossil fuels to natural gas.

“We can estimate how much smoke was actually in the atmosphere,” said Shane DuBay, a graduate student in evolutionary biology at The Field Museum and the University of Chicago and co-author of the study. “It might have been worse than the best estimates have predicted.”…

Read the whole story here.

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