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A bald eagle soars over the Potomac River near - |
By RUSTY DENNEN
A rare sight not long ago, bald eagles have made such a comeback that seeing one soaring overhead in much of the Fredericksburg area is almost ho-hum.
The Rappahannock River has its share of resident and migrating eagles, but another sweet spot is a stretch of the Potomac River from the U.S. 301 bridge north to Pohick Bay, a regional park on the river at Lorton.
Over two days in July, Jeff Cooper, a wildlife biologist and non-game birds project coordinator for the Virginia Department of Game and Inland Fisheries, and two colleagues counted 598 of the majestic birds of prey.
Cooper drove the boat while Sergio Harding, an avian biologist, and Jeannette Parker, assistant wildlife biologist, counted and logged the location of the birds.
After the trip, Cooper crunched the numbers and called Harding.
Cooper laughed, "He said he didn't believe me and wanted a recount."
Cooper spent three hours recounting the results, which were the same: 598, an incredible number and 88 more eagles than during a count in June.
It's the largest number of bald eagles ever documented in a summering area east of the Mississippi River.
Cooper has been doing surveys for eight years, but standardized the procedure and study area in 2006. Maximum counts for the past three summer surveys were 334 eagles in 2008, 375 in 2007 and 445 in 2006.
"The department used to focus on Mason Neck and Caledon," two areas along the river known for eagle concentrations. "But everywhere in between and below Caledon were not surveyed," Cooper said.
Caledon Natural Area in King George County is an eagle sanctuary; Mason Neck State Park is on the Potomac east of Occoquan.
"There was one notable place in Caledon, behind Jones Pond, where there's a communal roost," Cooper said. "We hit it in mid-morning and there were 60, 70, maybe 80 birds there."
Cooper said that while the count is not exact, it is carefully controlled and,
Cooper said the Chesapeake Bay region now supports about 1,000 nesting pairs of bald eagles. But their numbers are swollen at certain times of the year--in late summer and late winter--by eagles from Florida to Maine that are drawn to the bay's bounty of fish and waterfowl.
"Usually in the mid- to late spring, juvenile birds and [young] adults make a northern migration from Florida, the Southeast and Gulf states," Cooper said. "Food is driving all this, and they spend their summer here."
Adults, he said, come up after the breeding season, and numbers peak in June and July.
Then in December, "We start to see juveniles and adults from the Northeast and Canada." That peaks in January and February.
Hundreds of eagles have been counted in similar seasonal surveys by the Chesapeake Bay Foundation and the Center for Conservation Biology at the College of William & Mary.
Cooper said eagle numbers vary from year to year.
"A few years ago, we had low abundance in the concentration areas due to warm winters up north," which prompted migrants to stay closer to home, he said.
Cooper said the research is important in understanding where eagles congregate.
"One of our concerns is shoreline development," particularly along the Virginia shore of the Potomac where development has been chipping away at habitat. The highest concentrations, he noted, tend to be in undeveloped spots, such as Caledon.
The bald eagle population was decimated by pesticides in the 1960s and '70s, but has rebounded to the point that the birds were removed from the federal endangered-species list in 2007.
Rusty Dennen: 540/374-5431
Email: rdennen@freelancestar.com
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RANGE: Bald eagles are found over most of North America, from Alaska and Canada to northern Mexico. Nearly half the world's population of about 70,000 live in Alaska.
DIET: Eagles are especially fond of fish, but they also eat small mammals, waterfowl, seabirds and carrion.
BREEDING: During nesting, they prefer coasts, rivers and large lakes and return to the same nest year after year. Nests can be several feet across and weigh as much as 2 tons. Females lay an average of two eggs; incubation is 31 to 45 days.
CHARACTERISTICS: With a wingspan of up to 7 feet, adults develop the characteristic white head and tail by age 4 or 5, with a solid brown body and curved yellow bill. Juveniles have blotchy patches of white on their undersides and tails. Eagles live up to 30 years and are monogamous.
WHY BALD? Bald eagles are not really bald. "Bald" is a derivative of "balde," an old English word meaning "white."
--U.S. Fish and Wildlife Service |
