Wildlife experts believe there may have been 25,000 to as many as 75,000 nesting bald eagles in the lower 48 states when the bird was adopted as our national symbol in 1782. Since that time, the bald eagle has suffered from habitat destruction and degradation, illegal shooting, and contamination of its food source, most notably due to the pesticide DDT. By the early 1960s there were fewer than 450 bald eagle nesting pairs in the lower 48 states.
Bald eagles have few natural enemies. But in general they need an environment of quiet isolation; tall, mature trees; and clean waters. Those conditions have changed over much of the bald eagle's former habitat. .
In 1940, noting that the national bird was "threatened with extinction," Congress passed the Bald Eagle Protection Act which made it illegal to kill, harass, possess (without a permit), or sell bald eagles. In 1967, bald eagles were officially declared an endangered species (under a law that preceded the Endangered Species Act of 1973) in all areas of the United States south of the 40th parallel. Federal and state government agencies, along with private organizations, successfully sought to alert the public about the bald eagle's plight and to protect its habitat from further destruction.
The greatest threat to the bald eagle's existence arose from the widespread use of DDT and other pesticides after World War II. DDT was sprayed on croplands throughout the country and its residues washed into lakes and streams. There, they were absorbed by aquatic plants and small animals that were eaten by fish. The contaminated fish, in turn, were consumed by bald eagles.
The chemical interfered with the bald eagle's ability to develop strong shells for its eggs. As a result, bald eagles and many other bird species began laying eggs with shells so thin they often broke during incubation or otherwise failed to hatch. Their reproduction disrupted, bald eagle populations plummeted. As the dangers of DDT became known, in large part due to Rachel Carson's famous book Silent Spring, this chemical was banned for most uses in the U.S. in 1972.
In addition to the adverse effects of DDT, bald eagles also died from lead poisoning as a result of feeding on hunter-killed or crippled waterfowl containing lead shot and from lead shot that was inadvertently ingested by the waterfowl. (In 1991, a 5- year program to phase out the use of lead shot for waterfowl hunting was completed by the U.S. Fish and Wildlife Service.)
With these and other recovery methods, as well as habitat improvement and the banning of DDT, bald eagle populations have steadily increased. From fewer than 450 nesting pairs in the early 1960s, there are now nearly 4,500 adult bald eagle nesting pairs and an unknown number of young and subadults in the conterminous U.S. In the last few years, several states have had breeding bald eagles for the first time in years.
I hear the are pretty busy preparing for their stimulus funded vacation. Might have missed something
