Falco peregrinus anatum
Peregrine falcons (Falco peregrinus) have one of the widest distributions of any falcon species, occurring on all continents except Antarctica. The American subspecies, , F. p. anatum, inhabits western north America, from Mexico to Canada and Alaska. This falcon species was a resident on the Channel Islands in years past, but largely disappeared due to harassment, shooting, egg stealing, and reproductive failure caused by organochlorine pesticides, such as DDT. However, this species has made a comeback due to reintroduction efforts. Peregrines were reintroduced on the islands in the 1980s and as of 2013, there are 45 active peregrine falcons on the eight Channel Islands.
- The peregrine falcon is one of the most widespread birds in the world. It is found on all continents except Antarctica and on many oceanic islands.
- The name "peregrine" means wanderer, and the peregrine falcon has one of the longest migrations of any North American bird.
- People have trained falcons for hunting for over a thousand years, and the peregrine falcon was always one of the most prized birds.
- Formerly called the "duck hawk", peregrines are formidable hunters that prey on other birds (and bats) in mid-flight.
- Peregrines hunt from above and, after sighting their prey, drop into a steep, swift dive, or stooop, that can top 200 miles an hour.
This raptor is identified by its long, pointed wings and a long tail. Its shape as well as its size makes it stand out—the long primary feathers give the peregrine a long-winged shape. As with most raptors, males are smaller than females, so peregrines can overlap with large female merlins or small male gyrfalcons. Adults are blue-gray above with barred underparts and a dark head with thick sideburns. Juveniles are heavily marked, with vertical streaks instead of horizontal bars on the breast. Despite considerable age-related and geographic variation, an overall steely, barred look remains.
The peregrine is found on all continents except Antarctica and on many oceanic islands. Within Channel Islands National Park, a 2011 survey revealed that peregrine falcons are found on all five islands in the park. Although the numbers are not large, historic evidence shows that the peregrine was sparsely distributed on the islands. Owing to factors relating to the imperative of protecting nesting sites, peregrines tend remain in the Channel Islands for life.
Habitat for the peregrine is closely associated with the nest territory and their foraging areas. On the Channel Islands this generally would generally include coastal strands, bodies of water, and shorelines.
Foraging areas are associated with the nest territory. This generally includes coastal strands, bodies of water, shorelines, open grasslands, marshes and wooded areas. Peregrines hunt in the air, and the usual method of hunting prey is by attacking flying birds from above or chasing them from behind (Recovery Plan, 1982). Prey consumed by California peregrines is highly varied, nevertheless, they feed primarily on other birds, such as songbirds, shorebirds, ducks, and, in urban areas, starlings and pigeons. Flying high above their intended prey, peregrines will "stoop" or dive and strike in mid-air, killing the prey with a sharp blow. At no nest sites do peregrines concentrate on a single prey or few species. Peregrines are generalists which hunt the large variety of prey that occur in their home range (Walton, 1997).
Generally speaking, peregrines are monogamous, mate for life, and breed in the same territory their entire life. On the Channel Islands, pairs remain in the area around the nest cliff enough from July to January (i.e. the non-breeding season) to maintain possession of the nest site and drive out competitors (Walton, 1997).
Peregrines do not make stick nests; although they may use old common raven (Corvus corax) or great horned owl (Bubo virginianus) stick nests. The cliff usually has a small cave or overhung ledge large enough to contain three or four full-grown nestlings. Several holes or ledges that can be used in alternate years are apparently not an absolute requirement but probably increase the suitability of the cliff (Recovery Plan, 1982).
Peregrine falcons generally reach breeding maturity at 2 years of age. Usually, the male arrives at a nesting site and begins a series of aerial acrobatic displays to attract a mate. An average clutch of four eggs is laid in the spring, hatching about a month later. Peregrines vigorously defend their nests, although they may abandon them if severely or continuously harassed.
The use of DDT as a pesticide during the 1940s, 1950s and 1960s resulted in a precipitous decline of peregrine falcons in North America. During this period of DDT use, eggshell thinning and nesting failures were widespread in peregrine falcons, and in some areas, successful reproduction virtually ceased.
As a result, there was a slow but drastic decline in the number of peregrine falcons in most areas of its range in North America. By the time peregrine falcons were listed as endangered in 1970, the eastern population of the American peregrine falcon was gone and the populations in the west had declined by as much as 90 percent below historical levels. By 1975, there were only 324 known nesting pairs of American peregrine falcons.
An aggressive recovery program began in 1974 and resulted in over 6,000 falcons being reintroduced to the wild. Now there are about 3,000 breeding pairs of American peregrine falcons in Canada, Mexico, and the United States. Territory occupancy, nest success, and productivity are all at levels considered normal for healthy peregrine falcon populations.
In August 1999, the U.S. Fish and Wildlife Service removed the American peregrine falcon from the list of endangered and threatened species, marking one of the most dramatic successes of the Endangered Species Act. Post-delisting monitoring will continue until 2015.
Surveys in 2013 recorded a total of 45 peregrine falcon territories on the eight Channel Islands, and 27 of those territories had eggs or chicks by the end of April 2013. In 2013 there were 5 territories on Anacapa, 16 on Santa Cruz, 13 on Santa Rosa, 9 on San Miguuel, and 3 on Santa Barbara (Sharpe 2013).
- Peregrine Falcon Fact Sheet, US Fish and Wildlife
- All About Birds
- Comrack, Lyann A. and Randi J. Logsdon. 2008. Status Review of the American Peregrine Falcon in California. Department of Fish and Wildlife.
- Sharpe, P.B. 2013. Interim report on the 2013 peregrine falcon survey. Institute for Wildlife Studies, Arcata, California. Prepared for Montrose Settlements Restoration Program.
- US Fish and Wildlife Service. 1982. The Pacific Coast American Peregrine Falcon Recovery Plan.