There are several reasons that bald eagles became an endangered species including habitat destruction, hunting, competition with humans for food and exposure to chemical pesticides. The decline of the bald eagle began with European settlement of North America and was made worse by westward expansion.
The U.S. government began taking steps to protect bald eagles in 1940 with the passage of the Bald Eagle Act. In 1974 the U.S. Fish and Wildlife Service officially listed the bald eagle as a national endangered species. From then until 1995, the species was listed as endangered in 43 of the lower 48 states and as threatened in the other five. However, previous conservation efforts led to the status of the bald eagle being changed to a threatened species in all the lower 48 states.
In 2007 the Department of the Interior took the step to delist the bald eagle as either an endangered or threatened species due to the species' dramatic recovery. At that point, there were an estimated 9,700 estimated breeding pairs of bald eagles in the continental United States, compared to the approximately 417 breeding pairs that existed in 1963. Nonetheless, the U.S. Fish and Wildlife Service still considers bald eagles a protected species and has enacted policies to prevent their numbers from suffering another drastic decline.