peregrine falcon

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photo by Anthony Mercieca©

(Falco peregrinus anatum)

Peregrine falcons live mostly along mountain ranges, river valleys and coastlines, especially around mudflats, shores or ponds. By the 1950s, peregrine falcons were extirpated from San Diego County. Starting in 1982, peregrine falcons were released in San Diego County. By 1988 a few breeding pairs had become reestablished, mostly in the coastal regions. Breeding pairs have been identified in the vicinity of San Diego Bay, Point Loma, and National City.

At Sweetwater Reservoir, the peregrine falcon is an uncommon fall and winter visitor; casual in late spring and early summer. Occurrence of the peregrine falcon is generally associated with the arrival of their prey, the seasonal waterfowl population.

Population declines were due to use of organochlorine pesticides (DDT). DDT and its breakdown product, DDE, caused eggshell thinning, resulting in dramatic reductions in reproductive success in the late 1940s up until the 1960s. DDT was banned in Canada in 1970 and the U.S. in 1972.

The falcon was listed as Federally Endangered in 1970, State Endangered in 1971. The American Peregrine Falcon has since been delisted from the federal register in 1999 largely as a result of the nationwide ban on DDT and broad scale captive rearing and reintroduction programs. More than 6,000 American peregrines have been released since 1974. As of 1999, the estimated population of peregrine falcons is 1,650 breeding pairs in the U.S. and Canada, with additional birds in Mexico.