Northern Prairie Wildlife Research Center
Description: The peregrine falcon is a crow-sized bird with pointed wings, a narrow tail and a rapid wingbeat. Adults have slate-blue colored backs. The underparts are cream-colored with horizontal bars. This falcon has a black face pattern resembling sideburns.
Habitat and Habits: The peregrine falcon migrates along larger bodies of water, often close to waterfowl and shorebird concentrations, feeding primarily on birds (small to medium sized songbirds, shorebirds and waterfowl) and rarely small mammals, lizards, fish and insects. Peregrines pursue their prey from a perch or while soaring. Suitable nesting habitat is generally rocky cliffs 200-300 feet high, large stick nests of other species, tree hollows and man-made structures.
Distribution: The peregrine falcon has a nearly cosmopolitan distribution, breeding on almost every continent except Antarctica. The peregrine is a rare summer resident of the Black Hills and Slim Buttes, formerly breeding in South Dakota. This species is an uncommon statewide migrant in early spring and fall, with occasional sightings during the winter.
Conservation Measures: Peregrine falcon populations declined drastically between 1940 and 1970, when the species was federally listed as endangered. The pesticide DDT and its breakdown products accumulated in small birds eaten by peregrines. DDT concentration in peregrines caused eggshell thinning and breakage.
Efforts to reestablish peregrine falcons in South Dakota using a cross-fostering method were attempted in 1979 and 1980. Cross-fostering involves substituting chicks of one species for those of a closely related species in hopes that foster parents will successfully raise their adopted chicks. In this case, peregrine chicks were placed into nests of prairie falcons. Two young were successfully fledged in 1979 in the Black Hills using this method, but efforts were unsuccessful in 1980.
Cross-fostering is no longer recommended for raptors. Hacking is the main method now used in peregrine falcon restoration. Hacking involves placing 4-5 five week old peregrine chicks in an artificial structure on a cliff face, tower or building. The birds are cared for by human hack site attendants until released for fledging when they are 42-45 days old. Hacking success depends on safety from predators, minimal human disturbance and the presence of suffcient prey. The desired result of this effort is the return of hacked birds to the general area of the hack site as breeding adults, helping to reestablish a breeding population.
Reintroduction efforts have primarily concentrated on locations within the peregrine's historical range rather than new areas. In addition to hacking, successful peregrine management includes the protection of potential nesting sites from disturbance and development and pesticide monitoring in the peregrine's food supply and aquatic ecosystems.