BALD EAGLES—A Winter Discovery
By John Bendoritis, Seasonal Employee at Lake Accotink Park
Spotting a bald eagle is one of the big winter thrills for birders. Such sightings are a major part of documenting what appears to be the recovery of the bald eagle population. During last year’s December Christmas bird count, an event held throughout the nation, 115 bald eagles were spotted in one day around Ft. Belvoir.
Statewide, a record number of 446 eaglets were tallied, the offspring of 331 breeding pairs in Virginia. This number dramatizes a rebound initially triggered by the 1972 national ban on the use of DDT, a chemical that led to a precipitous drop in successful live eaglet births. The adult bald eagle is regal and familiar as our national symbol: a white feathered head and tail; fierce, hooked yellow beak; and proud piercing eyes almost as large as a human eye. An adult eagle stands nearly three feet tall and its black talons are set on feet about six inches long, large even for a raptor.
If you spot an adult bald eagle in the air from directly below, you should see the white of head and tail against the dark brown plumage of body and a wingspan extending to over six feet. Bald eagles do not develop their distinctive white head and tail plumage until about their fourth year. By then, their bills, legs and feet have turned a deep yellow.
In the air, the bald eagle reigns supreme. While circling several hundred feet above water, a bald eagle can spot a small fish below the surface, sweep into a graceful descent and snatch it with its talons in a routine show of predatory power. Its eye-sight is so sharp (at least four times more acute than a person with perfect vision) that it can identify prey as small as a rabbit from well over a mile away.
While migrating, the eagle can average 30 miles per hour, effortlessly gliding along on columns of air called thermals with occasional slow ponderous beats of its majestic wings. While courting, bald eagles perform breathtaking aerial displays includ-ing rapid dives and turns. Sometimes, where two bald eagles grasp talons in mid-air, they plummet in spiraling cartwheels to within a few feet of the ground before releasing talons. These aerodynamic marvels are rela-tively light and hollow-boned, the males averaging about nine pounds, females a few pounds heavier. Each skeleton weighs about a half-pound, its 7,000 feathers one pound.
Bald eagles often mate for life, and care for their newborn eaglets, which have a low survival rate. In the nest, adult eagles clench their powerful talons into harmless balls to spare chicks and coax them to take shreds of meat from their beaks. If fledglings survive, they will live to an average of 15 to 20 years, although some have been recorded living close to 30 years in the wild.
Bald eagles prefer to nest in trees with large canopies and high perches near water, where they can survey and prey for fish, a staple, but they will also eat waterfowl, mammals and turtles, both live and as carrion. Eagles are notorious for stealing carcasses and injured prey of such fellow scavengers as vultures, ravens and crows.
Usually eagles winter in this area from October through March; however, nesting pairs may stay through summer. Some popular spots for viewing bald eagles locally are Mason Neck State Park, the Accotink Wild-life Refuge on Fort Belvoir, Pohick Bay Regional Park, Riverbend Park on the Potomac and Huntley Meadows. The last two are Fairfax County Park Authority parks.
Article Published in the Winter 2003 ResOURces Newsletter