The challenge
DDT and related pesticides made bald eagle eggshells so thin that they broke, and shooting and habitat loss had pushed the species close to extinction in the lower 48 states.
The case
By 1963 only 417 nesting pairs of bald eagles were known in the lower 48 states. In 1972, as the dangers of DDT became known, in large part due to Rachel Carson's book Silent Spring, the US Environmental Protection Agency banned DDT and some related pesticides. In 1978 the US Fish and Wildlife Service listed the bald eagle as endangered across most of the lower 48, and worked with partners on captive breeding, reintroduction, law enforcement and protecting nest sites. By 2007 there were at least 9,789 nesting pairs, and the eagle was removed from the endangered species list. Estimates based on 2018–2019 data put the population at 316,700 individuals, including 71,467 breeding pairs.
Why it worked
Removing the main cause of decline, then actively protecting the species, brought a national symbol back from the brink. Bald eagles remain protected under other federal laws after delisting.
Sources
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