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U.S.A. and California Endangered (Falco peregrinus
anatum)
The peregrine falcon is similar in size to the prairie falcon (Falco mexicanus), and is usually found near a water source. Like the other falcons, the male is smaller than the female and is similar in color. The peregrine falcon has two different plumages: adult and juvenile. There are also some variations in plumage among the three North American subspecies.
Generally, the adult peregrine has a dark head with two dark, thick mustache markings and white cheek patches. With these markings it appears like the bird is wearing a helmet or hood. The upper parts are blue-gray and underparts are whitish with an unmarked breast and barring on the belly and leg feathers. The cere, eye-rings, and legs are yellow.
Overall, juvenile peregrine falcons have dark brown upper parts and buffy underparts with dark streaking. The cere and eye-rings are bluish and the leg coloration varies from green to yellow.
The peregrine falcon has rapid wing beats, resembling that of a pigeon, but its flight is direct. This stocky bird can dive (often referred to as stooping) at incredible speeds, up to 200 mph. If it soars, its wings are held flat. When perched, its wing tips reach, or almost reach, the tip of its tail.
Generally, the peregrine falcon is found in open habitats from tundra, savannah, and coastal areas to high mountains. It is most commonly associated with tall cliffs with wide open views which are used for perching and nesting and usually near a water source. Cliffs, ledges, caves, or small holes with protection from the weather provide nesting sites. Typically, this species breeds in woodland, forest, and coastal habitats. It is also found in many cities throughout North America, nesting on the window or other ledges of tall buildings, and taking advantage of the abundance of pigeons (as prey).
During migration, peregrine falcons may be found near marshes, lakes, and ponds with high concentrations of waterfowl, shorebirds, and other birds. Also, like many other migratory birds of prey, peregrines migrate along mountain ridges along both the eastern and western coastlines.
Peregrine falcons feed primarily on birds, usually the size of pigeons, but can take birds up to the size of geese. Occasionally, they prey on mammals, insects, and fish. In years of high lemming and vole populations, the breeding peregrines will take advantage of this and eat more of these mammals rather than birds. Because of their larger size, females can take larger prey.
Their main hunting tactic is to take a steep (almost vertical) dive while in flight and ambush the flying prey. They will also pursue prey in a low, fast flight, or attack passing birds from a perch. Some pairs hunt cooperatively; in this situation, the larger female dives for the prey first, and later eats first.
The nest (often referred to as an eyrie) of a peregrine usually consists of a rounded depression with accumulated debris occasionally lined with grass on ledges of cliffs, banks, dunes, mounds, and as mention, human-made structures. Though they are capable, peregrines rarely nest in old tree nests or cavities. Cliff nesting sites are typically used for many years and are located from 50 to over 200 feet above the ground. Although they may use a variety of structures for nesting sites, they are typically located near a water source.
Peregrines breed from early March to late August. The size of a clutch ranges from three to seven eggs with the eggs being laid at two or three day intervals. Incubation lasts between 28 to 35 days and is performed by both parents. The young fledge between 35 and 42 days of age. A second clutch may be laid if the eggs from the first one are destroyed or removed early in the season. In resident birds, pair-bonds stay strong year-round.
Peregrine falcon populations have seriously declined since the 1940's due to eggshell thinning from pesticides, particularly DDT, and PCB poisoning. Although a few harmful pesticides have been banned in the United States, many of the contaminants remain in the environment and are still hindering the recovery of some populations. Over the last few decades, many recovery programs involving captive breeding and releases have been operating throughout the United States and Canada and these have helped to increase the numbers of the wild populations. As of 1990, in California, high levels of DDE (the derivative of DDT) contamination still existed; the sources of contamination vary, but one was from an insecticide that was still being used in the Central Valley. In 1985, 77 nesting pairs were known in California, up from the 5 known active sites in 1970. Since 1973, the State of California has established three ecological reserves to protect peregrine falcon nesting sites.
Other threats to this species include competition with ravens and prairie falcons (Falco mexicanus) for nest sites. This fast and agile species is also popular among falconers; but because of its endangered status, peregrine falcons can no longer be taken from the wild for use in this sport.
The peregrine falcon has a worldwide distribution, more extensive than any other bird. Historically, in North America, the peregrine falcon bred in all but the south-central region Canada, throughout most of Alaska, south along the Pacific Coast to southern Baja California, and inland along the Rocky Mountains to southern Arizona, New Mexico, and western Texas. In the eastern United States, this species bred in the northeastern states and in a southwestern belt through Pennsylvania and the Virginias to Tennessee. There were several local populations throughout the western and mid-western states.
Many of the breeding populations within the continental United States, particularly in the east, were affected by high levels of pesticide contamination, eventually eliminating them from many areas. In the last few decades, some of the harmful pesticides, such as DDT, have been banned from the United States and with the help of captive breeding and release programs, several populations have been re-established in many areas of their former range.
In California, peregrine falcons are considered uncommon residents. Active nesting sites of this species are known from along the coast north of Santa Barbara, in the Sierra Nevada, and other mountains of northern California. Some of the individuals that breed farther north migrate into California for the winter months. During this time, peregrines can be seen inland throughout the Central Valley, and occasionally on the Channel Islands. Spring and fall migrants occur along the coast and in the western Sierra Nevada Mountains.
Order FALCONIFORMES, Family FALCONIDAE, Genus Falco, Species peregrinus
There are three North American subspecies of Falco peregrinus: F. p. anatum, F. p. pealei, and , F. p. tundrius. F. p. anatum breeds in Alaska, Canada, and throughout the western states, including California. F. p. pealei resides (breeds and winters) in the Aleutian Islands off the coast of Alaska and along the coast from British Columbia to Oregon; some of these birds may migrate south into California for the winter. F. p. tundrius breeds on the tundra of the Arctic throughout the northern most regions of North America and winters in Latin America.
None.
Duck hawk, peregrine, American peregrine falcon, great-footed hawk, ledge hawk, stone hawk, rock hawk, bullet hawk, and wandering falcon.
Wheeler, B. K., and W. S. Clark. 1995. A photographic guide to North American raptors. Academic Press, San Diego, CA, 198 pp.; Johnsgard, P.A. 1990. Hawks, eagles, and falcons of North America: biology and natural history. Smithsonian Institution Press, Washington, DC, 403 pp.; State of California, Dept. Fish and Game. 1990. California's Wildlife, Vol. II: Birds (D.C. Zeiner, W.F. Laudenslayer, Jr,. K. Mayer, and M. White, eds.). The Resources Agency, Sacramento, 407 pp.; Erlich, P. R., D. S. Dobkin, and D. Wheye. 1988. The birder's handbook: a field guide to the natural history of North American birds. Simon and Schuster, Inc., N.Y. 785 pp.; Clark, W. S., and B. K. Wheeler. 1987. A field guide to hawks: North America. The Peterson field guide series, Houghton Mifflin Co., Boston, MA, 198 pp.
Length:
male: 37-41 cm (14-16 inches)
female: 42-46 cm (16-18 inches)
Wingspan:
male: 94-100 cm (37-39 inches)
female: 102-116 cm (40-46 inches)
Weight:
male: 453-685 grams (1-1.5 pounds)
female: 719-952 grams (1.6-2.1 pounds)
Of the subspecies, F. p. anatum adults have darker heads, wider mustache marks, smaller cheek patches, and sometimes have a salmon (pinkish) wash on the underparts. Adults of F. p. tundrius are overall paler, with narrower mustache marks, larger white cheek patches, less salmon on underparts. F. p. pealei adults do not have any salmon wash, and are heavily marked on underparts, especially on breast, and even on the white cheek patches.
Of the subspecies, F. p. anatum juveniles exhibit the dark heads, wide mustache marks, small (buffy) cheek patches of the adults, but they also have chevron-shaped dark markings on their leg feathers. F. p. tundrius juveniles have paler heads, narrower mustache marks, narrower streaking on buffy underparts, and dark streaking on the leg feathers. F. p. pealei juveniles are overall darker. The coloration of their underparts vary from heavy streaking to nearly uniformly dark. Their legs are dark with lighter edges, and similar to the adults of this race, their white cheek patches have dark streaks.
The prairie falcon is similar in size to the peregrine falcon, but is overall paler and exhibits black wingpits or axillary marks (the underside of the wings where they meet the body). Also the mustache markings are much more pronounced on the peregrine falcon than the prairie falcon.
N. L. Brown