JUANA SUMMERS, HOST:
As winter loosens its cold grip on New England, morning bird song fills the air even before the sun comes up. But as the climate warms, backyard birds once seen as signs of spring, are now year-round residents. Maine Public Radio's Peter McGuire takes us out on a chilly morning to witness the change.
(SOUNDBITE OF BIRDS CHIRPING)
DOUG HITCHCOCK: These birds we're hearing right now are males. It tends to be males that do most of the singing.
PETER MCGUIRE, BYLINE: Maine Audubon's Doug Hitchcock cranes his head to catch sight of red-winged blackbirds bobbing and diving in the woods outside the group's headquarters. It's a bitter morning, and the blackbirds are getting ready for nesting season.
HITCHCOCK: They're making a ton of noise. They're fighting amongst each other so that then when the females show up, the males will already have their territories claimed.
MCGUIRE: Red-winged blackbirds are a sure sign spring is coming, or at least they used to be.
HITCHCOCK: It was always, you know, kind of the first week of March red-wing blackbirds would come back. And then, you know, a couple years later, it was, like, one of the last weeks of February, then a couple years later, mid-February.
MCGUIRE: Then two years ago, he says, Maine birders reported seeing red-winged blackbirds every single week of the year.
HITCHCOCK: These are still, you know, a small number of birds, but it's definitely, I think, kind of an early indicator of some of the changes that are going on here.
MCGUIRE: Climate change accelerated by fossil fuel pollution is tempering New England's notoriously fierce winters. That's helped alter the kinds of birds people see in their neighborhoods. Take the eastern bluebird, which used to migrate north as the weather warmed up. Now they're common and abundant in southern parts of Maine all winter long. And there's newcomers to get acquainted with. Less than a generation ago, sighting a red-bellied woodpecker sent a buzz through the birding community. Now, the historically southern birds are commonplace. Hitchcock says Carolina wrens, little brown birds with an outsized song, frequently generate midwinter calls from birders misled by out-of-date field guides.
HITCHCOCK: Up until, like, the '80s or so, Carolina wrens were barely into southern New England. So a lot of people see, you know, an old map like that and just think like, oh, this bird - it shouldn't be here. But that's really what the change has been.
MCGUIRE: This move north is happening across the country. According to the Environmental Protection Agency, the center of the winter range for hundreds of common bird species has moved north 40 miles since the 1960s. But it's also hard to pin expanding bird ranges on just one thing. John Garrett is from the Cornell Lab of Ornithology in Ithaca, New York.
JOHN GARRETT: What's really tricky is it's often really hard to disentangle what's climate change versus, you know, all of these other things that humans do that affect bird populations.
MCGUIRE: So habitat changes like regrown woodlands and suburban development give expanding species toeholds in new areas. Eastern bluebirds, in particular, got a boost from a birdhouse-building program. And feeders full of seeds, suet and mealworms help backyard birds weather the ever-shortening cold season.
For NPR News, I'm Peter McGuire. Transcript provided by NPR, Copyright NPR.
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