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Researchers place a band on the leg of one chick so the eagle may be identified if it is later captured or found dead.
Bart Paxton jots down data while Catherine Markham examines an eagle chick taken briefly from the nest along the river.
Paxton, of the Center for Conservation Biology, gently lowers a bag containing two eaglets. The nest along the Rappahannock River
The smaller of two eagle chicks awaits its turn to be weighed. The bird is covered with patches of down, and feathers are just beginning to emerge.
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IGHTY FEET ABOVE the ground in a crook of a swaying pine tree, Bryan Watts gingerly arched his hand over the rim of a 4-foot-wide nest, gently placing two downy, dull-gray bald eagle chicks into a cloth sack.
The 18-day-old birds chirped with alarm as their nervous parents circled high overhead. On one end of Watts' climbing rope hung the sack--a blue-and-white laundry bag from Target fashioned into a chick-tote.
"Here they come," Watts called down to biologist Bart Paxton and graduate student Catherine Markham, who were waiting at the base of the tree to receive the precious cargo.
Markham cradled the eaglets as Paxton measured their beaks, feet and wings with a caliper, jotting numbers in a spiral notebook. The measurements will help them determine the chicks' sex, which is not readily evident at this age.
The difference between the firstborn chick and its sibling was striking when it came time to weigh them on a portable scale. The larger of the two was a hefty 4.4 pounds--larger than your average roasting chicken--and the smaller, about half that.
Paxton banded the larger chick, then both birds were briefly admired by a gaggle of volunteers before being returned to the bag for the trip back up to the nest. Watts and his crew will return for another climb and more measurements in about three weeks.
The eagles have chosen some prime real estate: Their nest has a commanding view of a small marsh off the tidal Rappahannock above Tappahannock, in a grove of trees overlooking a small farmhouse and red hay barn.
Eagle parents are remarkably tolerant of the intrusion, Markham said. "They won't come down and hit the climber, but they will call and perch in a nearby tree." Having humans handling the chicks doesn't seem to bother them either, she said.
Real-time video chicks
The nest is one of about a dozen scattered around the Rappahannock, York and James rivers that are part of an innovative video-monitoring project by the Center for Conservation Biology at the College of William & Mary. Its exact location was omitted from this story to protect the eagles.
The project is unusual because it gives researchers real-time video images of what's happening in the nest. A cable attached to a small, bullet-shaped security camera installed above the nest runs down the tree, across the forest floor to a green plastic container about 100 feet away containing a video monitor and a VCR. A car battery supplies power for the equipment.
Watts, director of the Center for Conservation Biology, wants to know why some stretches of the Rappahannock, York and James rivers are producing so many more eagle chicks than others.
The varying salinity of tidal rivers and the availability of fish--eagles' food of choice--may have something to do with it.
"There's a stretch between a certain salinity zone and the fall line that seems to be where the highest breeding density is," Watts said. "If you look at chicks produced in the past few years, most of those come out of those parts of the river."
On the Rappahannock, that sweet spot runs from Tappahannock up to the fall line; on the James, above Williamsburg; and on the Potomac above the U.S. 301-Harry W. Nice Memorial Bridge.
As part of the effort, Markham is studying the influence of salinity on the birds' diet, how much food chicks are getting and what kinds of fish the eagles are catching.
Eagles need lots of fish in the early spring to feed their hungry brood. It's no coincidence that shortly after eagles hatch in late February and early March, shad and herring begin their annual spawning runs upriver.
"We've always thought that these runs were fueling those eagles," Watts said. Several dried-up gizzard shad carcasses littered the ground around the nest visited by Watts and his researchers on Sunday.
The video monitors will make the investigation that much easier. Technological advances have made the cameras and equipment more compact and less obtrusive.
Reaching new heights
Last year, the Center for Conservation Biology installed nine cameras at nests on the James and Rappahannock rivers; this year, 12 cameras will be operating on the York, Rappahannock and James.
Markham and Watts take turns climbing. It's dangerous, physically demanding and requires concentration. Before arriving at the Rappahannock site, Markham climbed to a nest on the York River. In that nest, she said, was a chick banquet: the remains of "the biggest catfish I've ever seen."
On one climb last year, Markham had a more scary encounter: A raccoon had taken over the nest and wasn't exactly happy to see her.
The center also enlists help from volunteers such as Judy Allen and Kevin Goff--both teachers--who recover and change videotapes at the monitoring sites. The nonprofit conservation center was founded in 1991. In 2001, the latest year for which figures are available, it conducted 25 wildlife research projects in seven states.
Eagles usually return to their nests year after year, arriving in late winter to make repairs with sticks and twigs. As the nesting time approaches, they line the center of the nest with soft grasses. A clutch of one to three oval, off-white eggs about a third larger than a jumbo chicken egg appears in early March.
On average, there is about one nest per mile of shoreline in prime areas. "But they're way in excess of that up here," Watts said of the Rappahannock.
Nesting pairs soar
Once a rare sight in Virginia, eagles have made a stunning comeback. In the early 1970s, there were an estimated 66 pairs in coastal Virginia. Aerial surveys this year indicate the number is close to 500 pairs, Watts said.
Cindy Hoffman, a spokeswoman for the Fish and Wildlife Service in Washington, said that bald eagles have made great strides in recent years and that some areas have been key.
"The Chesapeake Bay is a tremendous area for bald eagles," she said. The estuary supports not only resident eagles, but as many as 2,000 others that migrate up from Southern states during the year.
Bald eagles once thrived in every state except Hawaii. When America adopted the bird as its national symbol in 1782, as many as 50,000 nesting pairs lived in the lower 48 states. By 1963, according to the Fish and Wildlife Service, there were only 417.
Pesticides such as the now-banned DDT worked through the food chain and into eagles' diets. The bug-killer caused the birds to lay eggs with thinner shells, which tended to break during incubation.
In 1966, the Endangered Species Preservation Act was enacted; bald eagles were designated endangered the following year.
The eagles' recovery began slowly in the early 1980s and picked up momentum until July 1995 when they were reclassified from endangered to threatened.
The agency in July 1999 recommended that bald eagles had rebounded so well that they be dropped from the endangered-threatened list altogether, and put under the purview of the Bald and Golden Eagle Protection Act. This would still protect the birds, but there would be more flexibility for property owners.
The delay is over administrative issues. "We're still grappling with how to manage the species under that other law," Hoffman said.
Preserving habitat is also a concern in fast-developing coastal areas such as the Rappahannock and Potomac basins. That could be one of the biggest factors in limiting the birds' range, environmentalists say.
Watts said that scientists must know more about why so many eagle pairs choose certain areas for nesting sites.
"If we had to fall back and focus on some geographic areas at the expense of other areas, what would those be?" Watts said.
