With the advent of a new pesticide, DDT, in the 1940’s, the United States’ national symbol came under threat. DDT interfered with the eagle’s ability to produce hard eggshells which resulted in eggs that broke during incubation or failed to hatch. According to the U.S. Fish and Wildlife Service, there were only 487 nesting pairs of bald eagles at their lowest point in 1963.
Thankfully, the bald eagle’s listing under the Endangered Species Preservation Act and the banning of DDT helped save this iconic bird. “Based on the most recent population figures,” says the U.S. Fish and Wildlife Service, “the Service estimates that there are at least 9,789 nesting pairs of bald eagles in the contiguous United States.”