A Purple Sandpiper. Credit: Courtesy of Bob Duchesne

Not all Christmas gifts are happy ones. Schoodic Institute released a report over the holidays that revealed an alarming decrease in the number of birds wintering in the Acadia area.

The researchers compiled data from 50 years of Christmas Bird Counts on Mount Desert Island and Schoodic Point. While some species are doing better, many of Maine’s bird populations are doing worse. Some are doing much worse. Overall, numbers are down 43 percent.

I fear the numbers will look even worse once this year’s Christmas Bird Count results are tabulated. Anecdotally, I was already aware that sea ducks seemed sparse and harder to find this winter. I don’t remember a worse year. Or maybe I just haven’t been paying attention.

Any year can be good or bad. Variation is normal. But the declining numbers along a 50-year trend line are shocking, and hard to argue with. Bad things are happening, but what exactly?

It could be that sea duck populations are crashing. Or it could be that the populations are healthy, and the birds have simply gone elsewhere. Or both.

It probably varies by species. Common eider numbers appear to be way down, but maybe they just went farther south. The eider’s favorite food, the blue mussel, is declining in Maine from human harvesting, green crab predation and ocean acidification. For a while, it looked like many eiders had merely moved to greener pastures, nearer to Cape Cod and Martha’s Vineyard. However, eiders are showing signs of distress there, too.

I’m seeing far fewer scoters around Acadia this winter. Black scoters, surf scoters and white-winged scoters are still present, but not in the numbers I’m used to. We’ll see if this year’s Christmas Bird Count results are consistent with my observations. Buffleheads and long-tailed ducks also seem less numerous to me. Did they go somewhere else, or die off?

Climate change has certainly forced changes. Southern birds are moving north, and so are northern birds. Historically, Canada jays and boreal chickadees were present in the Acadia area. Nowadays, you’d be hard-pressed to find one anywhere along the coast south of the Canadian border.

Birds coming down from the Arctic show significant declines. American tree sparrow numbers have plummeted. It could be that the warmer climate simply means they don’t have to migrate as far south. Or perhaps changes in weather are disrupting the food supply on their breeding grounds. Purple sandpipers breed farther north than any other shorebird, and they are suffering the same fate as the sparrows.

American Tree Sparrow Credit: Courtesy of Bob Duchesne

Meanwhile, birds that are comfortable around people are doing better. No surprise, northern cardinals, wild turkeys and American crows are increasing. Oddly, blue jay numbers have dropped. I’m not aware of changes in their summer populations, so it may be that more of them are leaving Maine in winter.

Studies such as this one underscore the value of Christmas Bird Counts. The counts were started 123 years ago. The accumulated data over such a long period shape our understanding of environmental changes across the entire continent.

Birds are sensitive to small changes and they’re mobile enough to relocate in response. Such trends can foreshadow impending problems for people, such as changes in water supplies, bigger storms, poorer growing conditions and invasive species.

I’ll share a few more observations. I spent part of last week along the Realty Road west of Ashland, conducting surveys for the Maine Bird Atlas. This is the fifth and final year of research spearheaded by the Maine Department of Inland Fisheries and Wildlife. I walked the same sections of road last March and the year-to-year difference is dramatic.

Last winter, there was a finch explosion in the north woods. I have never seen so many white-winged crossbills, pine grosbeaks, evening grosbeaks, purple finches, pine siskins and common redpolls. This year, meh. I enjoyed a couple small flocks of redpolls, but not much else. Even many of the resident red-breasted nuthatches opted to spend the winter elsewhere.

This variation is normal. Forests go through cycles, producing more food some years, more growth in others. This year, the crop of cones and catkins is unimpressive, so most seed-eating birds have gone elsewhere to find food.

Alert readers have notified me that they are seeing the same trends at their bird feeders. Pine siskins are gone. Many American goldfinches have departed. Only evening grosbeaks seem to be on the upswing. With all these changes going on, at least winter birding in Maine isn’t boring.

Long-tailed Ducks. Credit: Courtesy of Bob Duchesne

Avatar photo

Bob Duchesne, Good Birding

Bob Duchesne serves as vice president of Maine Audubon’s Penobscot Valley Chapter. He developed the Maine Birding Trail, with information at mainebirdingtrail.com. He can be reached at duchesne@midmaine.com.