OXON HILL - Like a lot of people, it seems, bald eagles enjoy watching construction work.
Defying biologists' expectations, a pair of the threatened species has built a home here on the Maryland shore of the Potomac River, in the very midst of the construction of the new $2.5 billion Woodrow Wilson Bridge. The noise and commotion do not bother the birds.
In fact, they seem to like it.
The eagles spend their days watching hundreds of workers labor over the new bridge, thousands of cars and trucks zoom (or inch) by on the Capital Beltway and planes swoop in for landings at nearby Reagan Washington National Airport. They do occasionally break away from the action for some hunting.
"There are planes right here. The Beltway's right here. The bridge work is right here," said Mike Baker, the bridge project's environmental manager. "This pair could have taken any other area. But they choose this. They knew we were here."
First spotted six years ago in a nest several thousand feet from the Potomac, the two eagles have nested progressively closer to the river - and the construction - since then. They have hatched 13 eaglets in that time, including two this spring that have kept their parents busy delivering food to the nest.
The babies fledged over the Fourth of July weekend, getting the plumage necessary for flight, and over the past month have been in a flight training of sorts all over the construction site. They are particularly fond of several metal fences covered by a thick black felt and can often be seen perched on one not 40 yards from the Beltway.
"These young don't know any different," Baker said. "This is where they were born."
Wildlife experts say that as the bald eagle population makes a comeback, their natural nesting areas are reaching a saturation point and the eagles are seeking out more unconventional homes. The bald eagle's status was upgraded from endangered to threatened in 1995.
The number of nesting pairs in Maryland surged from 41 in 1977 to 338 this year, state officials say, and eagles in Virginia have seen a similar resurgence, to 410 pairs this year.
"What we're seeing now is some birds that have moved a little bit closer to that fringe of suburbia," said Craig Koppie, an endangered species biologist in the Chesapeake Bay field office of the U.S. Fish and Wildlife Service. He has studied the Wilson Bridge eagles since 1997 and says they're especially adaptable.
"These birds as parents have witnessed and are accustomed to this mosaic of the landscape - that being human activity on the water, air traffic and major highways," Koppie said. "They're here all year round, so they're identifying with the change."
The adult eagles - affectionately named George and Martha by the bridge workers (for the first U.S. president and his wife) - have thrived despite some poor luck when it comes to nests. Their first nest that officials noticed was in a thickly forested area off Oxon Hill Road, several thousand feet from the river.
In 1999, they moved to the shore of a cove off the river. But shortly after they finished building that nest, the tree holding it was illegally cut down by a contractor working on the National Harbor development nearby. The contractor was fined, and the eagles moved back to their first nest.
In 2001, they moved a few thousand feet south of the beltway. Three eaglets hatched there in the spring of 2002 before the nest came down in a storm. So last fall the eagles were at it again, building a new nest - this time on Rosalie Island, the closest they have ever been to the new bridge.
"This pair is very tolerant of the activity, and they're raising very tolerant offspring," said Stephanie Spears, an environmental specialist with the bridge project who has monitored the eagles. "I've personally grown attached to this pair, and I want to see them succeed."
They seem to be doing just fine. Their reproductive rate of 2.17 offspring per year is beating the Maryland average, which this year was 1.09 young per pair. The Wilson Bridge eagles don't seem to have much trouble finding food in the waters of the Potomac. They eat shad, catfish, American eel, snakes, ducks and goslings.
Work on the new 12-lane Wilson Bridge, meanwhile, is coming along nicely. The foundation work was finished in early June, and contractors are now building V-shaped support piers that will hold up the bridge deck. Officials expect the first six-lane span to open by early 2006 and the second two years later.
The Wilson Bridge eagles aren't the only ones who have moved closer to civilization. A pair was observed at Norfolk International Airport last year, having built a nest about 1,200 feet from the runway. One of the eagles was killed this spring when it collided with a plane, but a baby successfully hatched a few months ago and was cared for by the remaining parent.
Airport officials are planning to build a new 8,000-foot runway, which would be even closer to the nest, and they're thinking about taking down the tree with the nest in it to prevent future encounters.
"For the safety of the birds and the safety of the aircraft, it's probably best to encourage the birds to nest somewhere else," said Wayne Shank, the airport's deputy executive director.
The home of George and Martha and their babies, Woody and Spike, has been preserved forever under agreements with the Fish and Wildlife Service. While the new bridge will touch down on Rosalie Island not far from the eagles' nest, the southern tip of the island is off limits for development. And 84 acres on the north of the island have also been preserved for eagles.
But so far, they have preferred their noisier perch next to the construction.
"It is something to the imagination that a pair of bald eagles could possibly adapt to a workload like this," Koppie said. "It's like the land's in turmoil. But they seem not to be infringed by this at all."