Common eiders are seen floating in a group in this undated file photo. Credit: Courtesy of Bob Duchesne

Winter bird numbers are declining rapidly in and around Acadia National Park. That’s the takeaway from new research published Friday.

The paper published in Northeastern Naturalist analyzes 50 years of data from Christmas bird counts on Mount Desert Island and the Schoodic Peninsula. The authors found that overall bird numbers have declined by 43 percent since 1971. They say this matches larger patterns of bird declines across North America.

Waterfowl abundance showed big changes. Common eiders, long-tailed ducks, and white-winged scoters decreased, but harlequin ducks and hooded mergansers increased.

Nick Fisichelli, president and CEO of the Schoodic Institute, is one of the authors of the paper. He says some of the declines are consistent with a warming climate.

“Some of the northern species that are at the southern edge of their range limits here in Acadia like the boreal chickadee have essentially dropped out of the Christmas bird counts,” he says. “We don’t see it most years anymore.”

He says the Canada jay, or gray jay, is another northern species now rare in the area. But southern species like tufted titmouse and northern cardinal are increasing as they shift their ranges north.

Christmas bird counts are happening nationwide through Jan. 5. To find a count near you, visit Audubon.org.

This story appears through a media partnership with Maine Public.