ARI SHAPIRO, HOST:
Sometimes what we call the slug for a story turns heads all day long. The slug is the short phrase that identifies a story on our show board. Well, the slug for this next piece is eagles killing other rare birds. Here's the background.
Since the 1970s, when the pesticide DDT was banned and the Endangered Species Act took effect, the American bald eagle's population has roared back from near extinction. In Maine, the eagle population has surged from a low of 40 nesting pairs to more than 700. More eagles means they need more food. So for some other struggling bird species, the eagle's success has a menacing side. Maine Public Radio's Fred Bever reports.
JOHN DRURY: See, there's one.
FRED BEVER, BYLINE: Bird tour operator and scientific researcher John Drury pilots his old lobster boat in Penobscot Bay, about 15 miles off Maine's coast. He's been visiting a stony archipelago of seabird colonies here for decades. He watches a black-headed juvenile eagle ark into the air, and two gulls rising to chase it off.
DRURY: There's one. They're after him right now. See him?
BEVER: Around the bend, a handful of great cormorants - big, dark birds with long, hooked beaks - guard their nests. And out on a nearby ledge, several more young eagles loaf and watch.
DRURY: They've moved out here to forage close to the rich, delicious birds.
BEVER: From Drury's perspective, that's a problem. Those great cormorants living under the eagles' gaze are some of the last to breed in the U.S. Once extirpated here, the great cormorants have made a comeback, too, reaching a peak of 240 nesting pairs in the early 1990s.
DRURY: And there are 40 pairs this year. And the eagles have been attacking every colony every year, pretty much.
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BEVER: About 50 miles southwest in Casco Bay, state biologist Brad Allen is documenting declines in several avian species. This day, he's looking for great blue heron.
BRAD ALLEN: There's one right there.
BEVER: Is that an eagle or a great blue heron?
It's a great blue, a majestic, prehistoric-looking bird. When Allen last studied the species in the 1990s, he counted roughly 1,200 nesting pairs along the coast. Now the coastal heron population is a third of that.
ALLEN: So it's down quite a bit because, you know, we've actually witnessed some subadult bald eagles and the heron are getting in there, and it's just catastrophic.
BEVER: Allen says eagles are responding to a big drop in their traditional coastal prey - cod, salmon and other fish whose populations have been hurt by overfishing, dams and warming ocean temperatures. Seabirds face other threats, as well, but the eagles are putting real pressure on. And with their population growing around the country, it's an emerging issue for wildlife managers.
BRYAN WATTS: We are headed into a golden age for eagles. We haven't had this many eagles in the Chesapeake since colonial times.
BEVER: Bryan Watts directs The Center for Conservation Biology at Virginia's College of William and Mary. He says he can foresee a time when the issue becomes acute enough to force a new approach to eagle management.
WATTS: In terms of eagles, because of their status within our society, it's a discussion that's been put off, but ultimately we're going to have to face.
BEVER: Right now, the only real strategy to deal with rising eagle predation is to scare them off. Maine hosts the only U.S. population of Atlantic puffins, a clown-faced little avian popular with birders. During the nesting season, when the young are most vulnerable, volunteers are posted at some of their colonies here to wave off marauding eagles. But when humans aren't around, puffins, like other seabirds, may have to fend off a growing number of eagles on their own. For NPR News, I'm Fred Bever in Portland, Maine. Transcript provided by NPR, Copyright NPR.
