STEVE INSKEEP, HOST:
OK, the bald eagle is no longer endangered but it is, apparently, cranky. Our national symbol has made a tremendous comeback. This means that growing numbers of bald eagles see other bald eagles nearby, who may be rivals for territory. NPR's Elizabeth Shogren has our report.
ELIZABETH SHOGREN, BYLINE: Biologist Bryan Watts motors along the James River south of Richmond, Va., surveying for eagles.
BRYAN WATTS: Another bird around the corner up here; another four birds around the corner there.
SHOGREN: I just counted 16, 17, 18 - 19, wow. There are so many, you can't even count them.
Young eagles with mottled, brown feathers; mature ones with bright-yellow beaks and white heads; eagles soaring in groups, squabbling with osprey, and snatching up fish with their legendary talons. Forty years ago, you probably wouldn't see a single bald eagle here. Watts, who's a professor at nearby William and Mary, says a prime reason was just upriver.
WATTS: That's the mouth of Bailey's Creek, and that's the place where kepone was dumped into the bay.
SHOGREN: Kepone is a pesticide.
WATTS: It was dumped out on the ground, and made its way into Bailey's Creek and from there, it went throughout the Chesapeake.
SHOGREN: DDT was a more infamous culprit. Eagles kept reproducing, but their eggs didn't hatch. By the 1970s, there were no eagle nests on the James River and fewer than 500 nests in the whole country. [POST-BROADCAST CORRECTION: There were fewer than 500 nests in the lower 48 states.] Watts says that grim reality woke up Americans.
WATTS: We, as a society, decided when the population was declining, that that's not what we wanted.
SHOGREN: The U.S. banned the pesticides. The eagle went on the endangered species list; their nests became protected. That was enough to let the eagles flourish. They rebounded without the major struggles that still face wolves, condors and grizzlies. Now, more than 10,000 bald eagle pairs nest each year across the country. And nowhere is the bald eagle comeback more dramatic than on the James River, where they're clearly the dominate bird. But Bryan Watts says ironically, the more eagles there are, the tougher it is to be an eagle.
WATTS: It's a jungle, if you're an eagle right now on the Chesapeake Bay. You have to watch your back.
SHOGREN: For decades, as soon as an eagle reached maturity, it got to hook up and have babies. But now, Watts says, only about 1 in 5 does. That means hundreds of adult birds without mates or territory.
WATTS: Why don't we tie up here? And I can take you up to a nest that's right by this little road here.
SHOGREN: One of more than 200 nests now on the James River. It's 80 feet up in a loblolly pine.
WATTS: Eagles have long wing spans, and so they have a hard time flying through trees.
SHOGREN: So they build nests high in trees, at the edge of forests. The breeding season's over, but Watts can learn a lot from empty nests. The bones on the forest floor under this one tell him what these eagles fed their chicks.
WATTS: So these are from the heads of catfish.
SHOGREN: Watts says eagle pairs return to the same nest every year, and defend them fiercely. Nests like this one are coveted by all those adult birds without territory.
WATTS: And so it's like a game of musical chairs, but with bayonets. The thing is that eagles have tremendous weaponry. And so when they fight, it can oftentimes be to the death.
SHOGREN: When the interlopers win, they sometimes break up nests, and the chicks die. So these days, eagle parents have a new job. One parent has to stand guard while the other gets food. Back in the boat, Watts looks through binoculars at an especially striking eagle.
WATTS: Large female.
SHOGREN: He says it's clearly one of those young adults on the prowl for territory.
WATTS: Do you see how dull its bill is? That bill will turn to a real brilliant orange-yellow as it matures.
SHOGREN: Watts puts a positive spin on the challenges she'll probably face in the coming years. The extra time she'll likely spend as a single adult will give her the experience she needs to be a better hunter and provider for her chicks.
WATTS: To see these species adapting to the different situations, you know, and how they solve these different problems that they're faced with, I think it's way more interesting than what our static view of them has been in the past.
SHOGREN: Now that bald eagles are our nation's best conservation success story, Watts says it's a great time to see what they're really like, and maybe get some hints about why early Americans were so captivated by them that they chose the bird as their symbol more than 200 years ago.
Elizabeth Shogren, NPR News.