Bald Eagle

The bald eagle, with its snowy-feathered (not bald) head and white tail, is the proud national bird symbol of the United States—yet the bird was nearly wiped out there. For many decades, bald eagles were hunted for sport and for the "protection" of fishing grounds. Pesticides like DDT also wreaked havoc on eagles and other birds. These chemicals collect in fish, which make up most of the eagle's diet. They weaken the bird's eggshells and severely limited their ability to reproduce. Since DDT use was heavily restricted in 1972, eagle numbers have rebounded significantly and have been aided by reintroduction programs. The result is a wildlife success story—the U.S. Fish and Wildlife Service has upgraded the birds from endangered to threatened.
http://animals.nationalgeographic.com/animals/birds/bald-eagle/