As the federal government gears up to take the bald eagle off the endangered species list, biologists worry that the fast pace of waterfront development in key eagle habitat could make the majestic bird's robust numbers fleeting.
Just as the eagle is returning to its riparian roosts, people are snapping up waterfront properties at record numbers, experts say.
"There's a thin ribbon of land that both populations are really vying for," says Bryan Watts, a biologist at the College of William and Mary's Center for Conservation Biology. "Everybody wants to live along the waterfront. That's true of us — that's also true of eagles."
To get a close-up view of the problem, Watts takes to the skies on an aerial tour of eagle habitat. In a four-seater Cessna, Watts hugs the shorelines of the Potomac River south of Washington, D.C., at a low altitude of 200 to 300 feet.
Near the Chesapeake Bay, the Potomac is wide — four miles across in some places. Watts says this is some of the most important habitat for bald eagles in the country. The eagles that live here represent a large portion of the 7,000 eagle pairs that currently breed in the lower 48 states.
Eagles are everywhere along the rural and sparsely populated stretches of the river and its tributaries. In addition to a vibrant population of resident birds that breed here annually, thousands of other eagles use the area as an essential feeding ground.
Birds from Florida fly up in the summer and birds from Canada and New England fly south in the winter. The Chesapeake Bay region provides a comfortable climate and plenty of food. Below, Watts spots a solitary eagle standing on the frozen river, finishing a meal of duck.
For 20 years, Watts has been flying over this area, studying the return of the eagle to the Chesapeake Bay. The number of nesting pairs has soared to nearly 1,000, from a low of 60.
During his flights, Watts sees hundreds of eagles. Many adults — with chocolate wings and bright white heads and tails — sit on nests, incubating eggs. Eagles are territorial when they're brooding, but some of the nests are as close as only a quarter-mile apart. Watts points out the very high breeding density in rural areas close to large creeks.
Unfortunately for the eagles, they aren't the only ones who want to build their homes along this waterfront.
"It's just point after point being consumed by development here," Watts says. "It's just like a wave that's running right down the Potomac. And the land values are just going out of sight here. Look at all of the open patches here that have just been cleared in the last year for new development... thousands of units that are going to go in shortly here."
Watts says that when people move in, eagles move out. Only 4 percent of the eagles in Virginia nest close to developed areas.
Below, a new development high on a bluff overlooks the Potomac. Watts says eagles used to nest here. He points out a few vacant lots at the end of a cul-de-sac. Watts says the developer was restricted from building on these lots because they were close to an eagle nest.
The nest has been abandoned for two years since the development went in, Watts says, and the developer now will be able to build houses on those lots.
Watts worries that the pace of construction will pick up if the eagle loses the protection of the Endangered Species Act, as expected. Another law, the Bald and Golden Eagle Protection Act, would take over but there is concern that it won't do as much to protect nests and may not protect feeding areas at all.
Decisions about whether to develop private land will be crucial to the eagle's future because very little of the eagle's habitat is protected within wildlife refuges or parks. Watts says about 80 percent of the eagles in the Chesapeake Bay region nest on private property.
Without the safeguards of habitat, Watts predicts that the Chesapeake Bay eagle population will decline in the next three or four decades.
Changes in the Chesapeake Bay habitat will not just affect local eagles, Watts warns. Because eagles from the whole Atlantic Coast use this area, fewer eagles in the Chesapeake Bay will mean fewer eagles from Canada to Florida.