Scientists are puzzled by increasingly abundant bird species in Maine’s North Woods
By Susan Sharon, Maine Public
Amid the bleak reports about a precipitous loss in numbers and types of birds around North America and the rest of the world is a glimmer of hope in Maine’s North Woods. A new study has found something unexpected and scientists aren’t yet sure how to explain it.
More than three decades ago, a team of researchers undertook a project near Moosehead Lake to document how songbirds were being affected by commercial forest practices including clearcutting. They found that birds and logging can coexist as long as there are different ages and types of trees present across a large landscape. That was encouraging.
But, then, in 2019 concern about birds reached a fever pitch.
A study published in the journal Science set off alarm bells about the state of birds in the U.S. and Canada, finding North America had lost nearly 3 billion birds since 1970, including sparrows, blackbirds and finches. Researchers found a 29 percent decline over the past 50 years, with habitat loss the primary driver. And the main cause? Humans.
And, of course, climate change. The startling findings prompted the researchers to head back to the North Woods of Maine, at 10 million acres, the largest contiguous tract of undeveloped forest east of the Mississippi River.
They wanted to replicate their original study to see how birds in this region were faring. So, in 2021, crews began monitoring 300 sites in different forest habitats across nearly 600,000 acres.
The work continued the following year when Maine Public accompanied a team to several survey sites on the West Shore of Moosehead Lake. It was raining, it was just after sunrise and the dense woods were dripping wet.
Once in place, Jonah Levy and Jalen Winstanley carefully listened for distinct bird calls. For ten minutes they recorded and then compared notes on species they identified inside and outside a 50-meter radius.
The data they gathered were then used to compare to the previous study and to bird populations in the rest of the country. And now, the results are in.
“So, you know, scientists — we’re supposed to come on the radio and say ‘We can explain this. We don’t understand this. And sometimes science just does that to you,'” said John Hagan, an ornithologist and project director at Our Climate Common.
Hagan and others thought they’d find widespread declines of bird species. But that’s not what they found.
“Lo and behold, it’s mostly good news, you know, two thirds of the species that we encountered were increasing over the last 30 years,” Hagan said. “Some were decreasing, too, but we didn’t expect to see any increases.”
Thirty-three out of 47 species showed an increased abundance over 30 years. This is in sharp contrast to findings in the Breeding Bird Survey during the same timeframe. Those showed 35 of the same species declined regionally and across the continent. Hagan said it’s not clear why there is an increased abundance in Maine’s North Woods but he and other researchers have some theories.
“One is it’s a big, blank space on the map,” Hagan said. “And our hypothesis is: It’s functioning like a bird sanctuary. It’s producing birds. Those birds tend to come back to where they were born. I just think it’s bizarre and unexpected. And really good news given all the dire news we always get about biodiversity.”
Despite the widespread increases, 14 bird species show a decline in abundance in the study area and Hagan said that merits closer examination. There may be forest practices that could help aid their recovery. The study could also have implications for bees and other insects as well as for overall forest management. Hagan said the search for answers will continue, but for now he’s taking some time to celebrate.
This article appears through a media partnership with Maine Public.