Millsap says a second round of surveys is occurring right now. The plan is to have surveys take place every three years from now on. Other sources of data can hint at what's going on with Bald Eagles, too. Geological Survey and their counterparts in Canada, dispatches skilled volunteers to count birds along set routes across the continent during the breeding season each spring.
The data showed a 5 percent annual increase in Bald Eagle numbers across the continent. The eagle population boom will almost certainly flatten out eventually. When it does, it may be due to the species naturally hitting its carrying capacity — a term used in ecology to define the maximum population size a region's resources can sustainably support.
But wildlife managers remain on the alert for new threats. While DDT may be a thing of the past, other toxins both new and old continue to worry those charged with ensuring Bald Eagles' continued success.
Although they hunt fish and other prey, Bald Eagles are also frequent scavengers, and a gut pile left behind by a game hunter represents a tempting meal. These carcasses often contain fragments of lead ammunition , which eagles and other scavengers gulp down along with the meat.
Even very small amounts of lead contamination in scavenged meat can be enough to kill an eagle. The lead problem isn't new. It helped motivate the banning of lead shot for waterfowl hunting in , which reduced Bald Eagles' exposure in the wetlands and lakes that are their preferred habitat. However, as populations have grown, more and more individuals have moved into upland areas where the hunting of deer and other large animals is common. Mercury, another heavy metal, is also raising alarms for predator species around the world as it accumulates up food chains.
Immature Bald Eagle with lead poisoning by Marge Gibson. Other pesticides whose effects aren't yet well understood have entered the market, such as brodifacoum, one of a broader class of chemicals known as second-generation anticoagulant rodenticides, or SGARs.
Although there were only five known Bald Eagle deaths from brodifacoum poisoning between and , compared to from lead, it's beginning to show up at chronic low levels in even the most isolated Bald Eagle populations, which wildlife managers are at a loss to explain. While the future is impossible to foretell, people who know Bald Eagles the best are optimistic about what's ahead.
It's impossible to see an adult Bald Eagle soaring overhead without feeling something — a flash of recognition, or maybe even a surge of hope. Thanks to a patchwork of environmental laws and the efforts of scientists, conservationists, and government agencies, more of us have the chance to experience that today than at any time in the past half-century.
There are many more success stories waiting to happen: 41 U. For now, though, the Bald Eagle remains a star. Act by December 31! Donate Now. Toggle navigation. Birds Priority Birds. Watch List. Bird of the Week. The Search for Lost Birds. Bird City Americas. Habitat Loss. During the s and s the use of pesticides, especially DDT, became a major problem. DDT residues accumulated in fish, a major food source of eagles.
The residues then accumulated in the eagles that ate the fish and subsequently caused a thinning of eggshells. DDT is now banned in the United States. Shooting, trapping, poisoning, and human disturbance continue to be a problem. Bald eagles can be electrocuted when perching on power lines. Wounded or sick eagles should be reported immediately to a wildlife agency.
There are many rehabilitation centers throughout the country that can care for eagles. Report new nests to the state wildlife agency. The bald eagle is the national symbol of the United States. Fish and Wildlife Service, If you encounter any problems with the files provided on this page, please contact Webmaster at The following printer-friendly version requires Acrobat Reader.
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