WILLIAMSBURG (AP) — An aerial survey of Virginia’s bald eagles turned up 485 pairs of the birds and 705 chicks along the lower Chesapeake Bay and its tidal tributaries.
“We’ve far exceeded our wildest expectations,” compared to when the survey began in 1977, said ornithologist Mitchell Byrd, past director of the Center for Conservation Biology at the College of William & Mary.
The center conducts the annual survey along the York, Rappahannock, Potomac and James rivers.
Each March, biologists conduct an aerial inventory of nests and check for nesting activity. They fly over tributaries and shoreline along the lower Bay again between April and mid-May to look for chicks.
Ninety-five percent of the bald eagles in the state nest in the Bay’s tidal tributaries.
Last year’s survey found 429 active nests with 657 chicks, up from 401 nests and 612 chicks in 2004. In 1977, Mr. Byrd counted 33 pairs.
The center’s director, Bryan D. Watts, said Virginia’s bald eagle population has grown between 8 percent and 10 percent annually since 1977, but the growth rate is beginning to decline because of diminishing habitat caused by development.
Mr. Watts said he expects the population to level out between 1,200 and 1,500 pairs in the Virginia-Maryland region in the next decade.
“Space is becoming limited because you have birds competing for territory, fighting for territory,” Mr. Watts said. “They’re starting to fill up available space and we are filling up the rest of the space.”
Nationwide, the U.S. Department of Fish and Wildlife estimates there are 7,000 bald eagle pairs in the continental United States, up substantially since the early 1960s, when the population was slightly below 400 pairs, Mr. Watts said.
The bald eagle has rebounded so strongly that the U.S. Fish and Wildlife Service is weighing whether to remove it from the federal threatened-species list.
The eagle first received federal protection in 1940.
The population stabilized briefly but then plummeted from the 1950s to 1970s primarily because of the pesticide DDT, which accumulated in the fatty tissue of female eagles and other birds, causing females to lay thin-shelled eggs that broke easily.
DDT was banned in 1972.
Over the past few decades, bald eagles have faced increased interaction with humans.
Eagles prefer isolation, but in recent years, nests have been found where they once were never seen, and development has caused them to build nests increasingly closer to one another.
Federal protections establish buffer zones around eagle nests, preventing or restricting construction and other human activities in given areas and at certain times.
Mr. Watts said a 2003 study estimated the land within a quarter-mile of Virginia’s eagle nests — the extent of a less restrictive, secondary buffer — was worth $1.7 billion.
With the increased human population and building demands, Mr. Watts wonders whether federal officials, despite their assurances, would enforce buffers as strictly if eagles no longer are listed as a threatened species.
“The question is not what happens to bald eagles now,” Mr. Watts said. “The question is how do we protect them into the future.”