Janeas Munden Bradley held her breath for a long moment considering the peril at hand. Four huge crows, potential predators of small or defenseless wildlife, were circling the massive bald eagle nest high up in the crotch of a loblolly pine tree.

An hour earlier, while the adult eagle couple was temporarily away, Bradley had climbed the 80 feet to the nest, removing the 8-week-old chick she found there and replacing it with two 3-week-old eaglets.

The 8-week-old bird, which had to be moved because it might endanger the two younger eagles, was then shifted to another next that it would share with a baby eagle the same age.

The reason for the transplant, the first in the Chesapeake Bay are bald eagle habitat located in Westmoreland County, Va., was to bolster the region's failing bald eagle population.

The bald eagle is the country's national bird and its population has been dwindling rapidly in recent years. The transplant project, headed by Stanley N. Wiemeyer, a biologist at the Patuxent Wildlife Research Center in Laurel, Md., is designed to increase the eagle population by placing chicks born in captivity in the nests of adult eagle couples in the hope that they will be adopted. But the presence of the crows in the eagles' absence threatened the project.

Bradley's transplant was the first one attempted in this area. Ideally, the eagles in the next, which weighs in excess of one ton, would adopt the 3-week-old chicks and the eagles in the second nest would adopt the 8-week-old chick when it was placed there.

In the meantime the eagle couple which had produced the 3-week-olds at the research center would be free to produce more chicks. In effect, they are being used as breeders.

Wiemeyer has a total of four breeding pairs at Patuxent currently and they have produced seven chicks this year. One of the other five has already been transplanted successfully in upstate New York and the other four will be sent there later in the year.

At one point in the 1930s there were several thousand eagle couples in the U.S. Wiemeyer estimates the current population to be between 1,000 and 1,200. In the Chesapeake Bay area the population, once estimated at 250 couples, is down to about 80.

"There are a number of reasons why the eagle population has dwindled," Wiemeyer said. "DDT and other pesticides are certainly a major factor. And, believe it or not, people still shoot eagles even thought it's been illegal since the 1940s. Destruction of habitat is also a problem: people clearing away trees for housing projects."

Wiemeyer hopes someday to bring the eagle population in the Chesapeake area back up to 175 couples. He is hoping for an eventual 75 percent transplant success rate. Right now though, his first concern is the initial transplant, which took place Friday.

"We'll be monitoring both nests during the week," he said. "Right now it's too soon to tell if the adults will accept the chicks, but the first indications are good."

Friday, as Bradley crouched watching the nest, it appeared that the adult eagles might not return. "I just know they'll be back," she said nervously. Bradley knew that because the couple had been scared out of the nest by humans twice already this season, they might not want to return to the nest area to defend the chicks.

But just when it seemed the crows would swoop down on the nest, one of the eagles returned. As the eagle glided toward the crows, they scattered.

Bruised in several places from her climb into the nest, Bradley got up to leave. The first step had been taken in a project those at Patuxent hope will take the bald eagle off the endangered species list.

"People have known that the eagle was in danger since the 1950s," Wiemeyer said. "But it wasn't until the '60s that anyone took any action. Now we're hoping to make some progress in the other direction."