A history of searches for black-footed ferrets

Studies of wild populations of black-footed ferrets (Mustela nigripes) in South Dakota in the 1960s, in Wyoming in the 1980s, and of captive-bred ferrets reintroduced to unoccupied habitat in Wyoming, South Dakota, and Montana in the 1990s contributed to our understanding of ferret behavior and improved techniques to find ferret populations. We chronicle the efforts of private, State, and Federal institutions that used these techniques to locate remaining populations of ferrets. During the 1980s, a renewed survey effort and solicitation of new sightings, coupled with a monetary reward program, failed to locate ferrets. We believe that the probability of finding ferrets from noncaptive stock is already small and diminishes with each passing year.