Biologists celebrate comeback of endangered ferret

Wildlife biologists say the black-footed ferret, once believed to be extinct, has made a comeback in the 30 years since its rediscovery. And celebrations are under way nationwide.Badlands National Park in western South Dakota kicked off its three-day festival by releasing four of the endangered animals into the wild to do what they do best: attack and kill prairie dogs.The ferrets were thought to have died out in the late 1970s. But a ranch dog in Wyoming presented a dead one to his owners in September 1981, which launched a recovery effort. In the three decades since, the ferret population has grown from 18 in the wild to more than 1,000.Conservationists say they hope to be able to remove the ferret from the endangered-species list by 2020.