U.S. Navy photo by Gary Wagner Dr. Bryan Watts (left), NSF Indian Head's Seth Berry and Libby Mojica (right) band eaglet on both legs.

The team, which includes NSF Indian Head Natural Resource Manager Seth Berry, is conducting the survey as part of a vital national drive to ensure the bald eagle will always be available for future generations of Americans.

The American bald eagle will soon celebrate two important anniversaries. It was chosen as the official emblem of the United States because of its long life, great strength and majestic looks June 20, 1782. On June 28, 2007, the Interior Department took it off the Endangered Species list.

Only three decades ago there were genuine fears that the eagle might go extinct, as there were believed to be less than 500 active nesting pairs in the 48 contiguous states — radically down from the more than half-a-million when it was picked as the national bird by Congress. The use of certain chemicals such as the pesticide DDT and also oil, lead and mercury almost proved to be the bald eagle’s undoing. But aggressive conservation efforts and studies, such as this one at Indian Head, helped it make a remarkable comeback.

Dr. Bryan Watts, director of the Conservation Biology Dept. at the College of William and Mary, and Libby Mojica, a research biologist at the college, headed up the cooperative bald eagle survey of the Indian Head and Stump Neck Annex sites.

Berry explained that the survey of the sites was a requirement by the U.S. Fish and Wildlife Service of the Interior Dept. and that ‘‘it is a three-year study designed to look at how bald eagle populations are progressing at Indian Head and Stump Neck. It also includes some aerial surveys,” he said, ‘‘and will take in any new nest sites and numbers of eaglets and eggs. We believe that there are 10 current nesting sites at Indian Head and Stump Neck, and eight of them are active ones.”

The survey meant that the biologists would have to climb up into the high aerie of the eagle, retrieve the eaglets and perform vital examinations to include banding, blood sampling and other general health and physical screening. All would have to be done while the mother eagle soared above, squawking threatening protests. The first site chosen was a natural area off of Roach Road at the Stump Neck Annex.

Watts was particularly pleased with the chicks he retrieved. ‘‘They look well cared for and in good health,” he remarked.

The William and Mary professor said that the bald eagle has made a remarkable comeback, especially in the greater Chesapeake Bay area. ‘‘There were less than 30 nesting sites in Virginia back in the 1970s,” he said. ‘‘Today we believe there are more than 600 in Virginia and about that many in Maryland.”

Again, the pesticide DDT was blamed for the crisis that decimated America’s national symbol. According to biologists, the pesticide itself was not lethal to the bird but it drastically interfered with the eagle’s calcium metabolism, rendering it either sterile or unable to lay healthy eggs. Often the females, largest of the two mating eagle pair, would lay eggs too fragile to withstand her weight, making it impossible to bring eaglets into the world. Other factors impacting on the decline of the bird included loss of habitat, illegal shooting and pollution factors from heavy metals such as lead and mercury. But, thanks to conservation efforts, the bald eagle today need no longer contend with these chemical hazards.

They have, however, increasingly come into deadly contact with a different man-made hazard – high-voltage electrical lines. According to Berry, from 2001 to 2005, the Natural Resources Office at Indian Head recorded 13 bald eagle deaths. Eleven of those deaths were contributed directly to electrocutions or line-strikes.

Accordingly, the office met with the U.S. Fish and Wildlife Service to develop ways to aggressively counter these accidental eagle deaths. In 2005, the office developed the Raptor Electrocution Prevention Study (REPS) as a proactive measure in addressing the problem, which surveyed the electrical distribution system at Indian Head and Stump Neck to determine what was causing the distress to bald eagles and other raptors.

The survey identified five priority zones based on highest risk of negative impact (factors contributing to the determination included presence of a bald eagle nest, previous electrocution or line strike, flight patterns and foraging areas).

‘‘Mitigation for the negative impacts included retrofitting the electrical distribution system by installing flight diverters on the utility lines at 30-foot intervals, installing plastic phase covers on the middle phase to prevent electrocutions and installing 60-inch fiberglass cross-arms,” Berry said, explaining that typical eagle’s wing spans are 60-inches and therefore installing phase covers and new cross-arms will prevent the eagle from making contact with two phases at the same time.

The Natural Resources Office also maintained bald eagle nest protection zones during the nesting season from Dec. 15 to June 15 as recommended by the U.S. Fish and Wildlife Service.

All base activities, MILCONs (military construction) projects, training areas, ranges, grounds maintenance and hunting activities were regulated within these zones. Land use and vegetation removal is also regulated. USFWS was consulted on any action that potentially posed an adverse affect to the nesting bald eagles. The USFWS also reviews the consultation letter and then issues a letter of no adverse effect or letter of adverse effect that would detail restrictions and mitigation, if required.

The Navy, though, is taking the lead in also trying to reduce those kinds of hazards by placing objects of high visibility on installation power lines to ward off accidental meetings with the birds, and using other devices to discourage their nesting in places where high aircraft traffic is hazardous, Berry said.

Watts said that other than man-made ones such as power lines, adult eagles have no other real threats to their lives.

‘‘Raccoons and the Great Horned Owl sometimes will take the chicks,” he said. ‘‘But that’s only when the adults are away.” Eagles, by nature, are very protective of young and share some other characteristics of human beings.

‘‘We have found that some pairs keep their nests clean and tidy but, in other cases, some of the nests are just plain messy,” he said. He also noted that Mr. Eagle is usually the principal bread winner for the family while Mrs. Eagle stays mainly on the nest and ‘‘takes the food away from him” then demands that he go out and search for more. ‘‘The female is the dominant bird,” he said.

But eagles know a thing or two about long marriages. ‘‘There is no divorce rate among eagles,” Watts explained. ‘‘They are monogamous and mate for life. They will not seek or choose another mate unless the other dies.”

The diet of most eagles is seafood; that is why they like to build nesting sites close to water areas. ‘‘Up to 95 percent of their food is fish or other aquatic life,” Watts said, ‘‘but they will also eat squirrels, muskrats, rabbits and they seem to especially love turtles.”

Eagles eat food by holding with its long talons and tearing with its sharp beak. Females grow to between 10 and 12 pounds, with males usually in the 7-9 pound range at adulthood.

‘‘They usually live to about 28 years in the wild,” Watts noted. ‘‘But we believe that they can live quite a bit longer. Our banding program is showing that they are breaking previous records for longevity now.” He added that eagles are believed to be reproductive their entire life.

Mojica said that the young eagles usually are ready to test their wings at about 11 weeks. The young ones, though, still have a lot to learn in hunting and fishing techniques from their parents and, so, hang around the aerie as teenagers most of the summer. After that they are on there own.

Biologists, Watts said, don’t really know a whole lot about eagles between the time they fledge and go out on their own and the time they are sexually mature adults (about 3 years) and are ready to mate and set up housekeeping. ‘‘That’s an area we want to explore,” he pointed out.

When they do begin seeking out mates, the pair will build the largest nests of any North American bird. Limbs as big as 4 inches in diameter will be used in the aerie and the nest will dominate the entire top of the highest trees in a coastal forest.

The nests appear to be as large as a typical family-sized kitchen table in many cases. The nests also appear to be extremely durable, able to withstand any storm. Watts pointed out that the aeries also are constructed ‘‘with outside fences” so that the young eaglets don’t risk falling out. The young ones are pretty content to stay in the nest, mostly sleeping and eating until they get ready to fledge,” he said.

‘‘A typical nest will have about two birds,” Mojica said. ‘‘The number of chicks produced will vary from pair to pair. Sometimes there’s only one but usually two to three chicks are born. It takes them about seven or eight weeks to reach a nominal weight then they are ready to fledge at about 11 or so weeks. They get ready by continually exercising their wings and grow stronger day by day in hopes of a long lifespan.”

Thanks to the conservation and study done at Indian Head that lifetime is not only longer, but more productive.