|
Habitat and Distribution: Distributed worldwide, Peregrine falcons are found on every continent except Antarctica. They can be found breeding in the arctic tundra, through Europe and North America, and south into Africa, South America, the Pacific Islands and Australia.
Peregrine falcons are birds of open spaces usually associated with high cliffs and bluffs overlooking rivers and coasts.They can be found from sea level to 12,000 feet in a wide variety of habitats including the tropics, the desert, maritime habitats and the tundra. Recently, many cities with tall buildings have become home to pairs of peregrines. Many populations are migratory (their name means "wandering falcon") and will travel great distances.
Status in the Wild: The Peregrine Falcon was listed as an Endangered Species by the U.S. Fish and Wildlife Service in 1972 following the catastrophic decline of the species worldwide. In response and after the banning of DDT, the Peregrine Fund, a non-profit organization, was founded with a mission to reintroduce the species into North America. Some of the earliest reintroduction sites included historic nesting areas in Pennsylvania during the 1970s. The Peregrine has subsequently experienced one of the most dramatic recoveries of any endangered species, and was formally removed from the federal list in 1999.
 |
Photo by Ryan Clausen
|
Habits and Adaptations:
A Peregrine in steady flight has shallow but powerful wingstrokes, similar to those of a Cormorant. When in active pursuit of prey, the falcon's wingstrokes become deeper. When Peregrines soar, they hold their wings flat and fan out their tails fully, making them appear diamond-shaped. While soaring, their wings are fully extended, and the wingtips appear broad and rounded, in contrast to their normally sharp-pointed appearance. In a dive (known as a stoop) the wings are folded in close to the body.
Peregrine populations were once endangered due to pesticides like DDT. DDT causedthe female to lay thin-shelled eggs that were easily broken, resulting in the death of the developing embryo inside. After the banning of DDT in the United States, The Peregrine Fund released more than 4000 captive-reared birds in 28 states over a 25 year period.
Peregrine falcons have adapted to living in many cities. Cities offer tall buildings with ledges for nesting, water sources, large populations of pigeons and starlings for food, and have few natural predators.
Thier calls are loud, harsh, and raucous. Adults cack, chitter, eechip, and wail. Young beg with arepeated "screea, screea, screea" sound.
Breeding and Maturation: Peregrine falcons frequently nest near water on ledges of rocky cliffs or buildings, but occasionally will use abandoned stick nests of other species. They do not build nests, but scrape a small depression out of the soil. Peregrines lay 3 - 4 eggs, which are incubated for about 34 days. The young falcons fledge 5 - 6 weeks after hatching.
If a Peregrine falcon lives through its first year, it can live up to ten years or more. However, most young birds do not survive their first year, with an estimated first year mortality rate of 50-80%.
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. Peregrines vigorously defend their nests, although they may abandon them if severely or continuously harassed.
Lifespan: Up to 20 years in the wild. The oldest female in Midwest (as of 2004) was 18 years old and still holding a territory in St. Paul. She has nested 16 times, has had 6 mates, laid 60 eggs, and fledged 43 young. Her last successful nest was in 2001 at age 15. The oldest male, also 18 and still alive in Chicago, sired 5 young in 2003. Most peregrines die long before they reach old age.
Conservation Issues: Peregrine falcons were taken off the endangered species list in August 1999. They are currently still bred in captivity for release into the wild and for falconry.
Peregrine falcons have never been very abundant. Studies in the 1930's and 1940's estimated that there were about 500 breeding pairs of peregrine falcons in the eastern United States and about 1,000 pairs in the West and Mexico. Then, beginning in the late 1940's, Peregrine falcons suffered a devastating and rapid decline. By the mid-1960's, the species had been eliminated from nearly all of the eastern U.S. Although less severe, the decline spread west, where Peregrine populations were reduced by 80 to 90 percent by the mid-1970's. At that time, only the populations of Peale's falcons nesting along the north Pacific Coast in Alaska and British Columbia appeared to be stable.
Scientists at the U.S. Fish and Wildlife Service's Patuxent Wildlife Research Center near Laurel, Maryland, began investigating the Peregrine's decline. They found unusually high concentrations of the pesticide DDT and its breakdown product DDE in Peregrine falcons and other birds of prey. The Peregrines accumulated DDT in their tissues by feeding on birds that had eaten DDT-contaminated insects or seeds. The toxic chemical interfered with eggshell formation. As a result, falcons laid eggs with shells so thin they often broke during incubation or otherwise failed to hatch. Because too few young were raised to replace adults that died, peregrine populations declined precipitously.
In 1970, the American and Arctic Peregrine falcon subspecies were listed as endangered under the Endangered Species Conservation Act of 1969 (the law preceding the Endangered Species Act of 1973) reflecting their critical biological status. Because DDT and other pesticides were not used in the areas where Peale's peregrines live, these falcons declined to a lesser degree and were not listed. In addition, Peale's peregrines were not susceptible to picking up DDT in other areas because they do not migrate and feed largely on non-migratory prey.
In 1972, DDT was banned for most uses in the U.S. However, DDE residues are still found in some areas of the country, and DDT continues to be used in many Latin American countries where some Peregrines and their prey spend the winter.
The Fish and Wildlife Service established Peregrine falcon recovery teams comprised of Federal, State, and independent biologists to recommend actions necessary to restore peregrines in the U.S. As part of recovery efforts, scientists at Cornell University successfully bred and raised peregrine falcons in captivity.
Under a cooperative effort among the Fish and Wildlife Service, State wildlife agencies, The Peregrine Fund, Santa Cruz Predatory Bird Research Group, and the Midwestern Peregrine Falcon Restoration Project, more than 6,000 birds have been released since 1974. Large-scale reintroduction of Peregrines have ceased due to the Peregrine's recovery, and relatively few reintroductions are still taking place in the United States.
Populations of Peregrine falcons are now estimated to be about 1593 breeding pairs in the U.S. and Canada, with additional birds in Mexico. In recognition of this bird's recovery, the Fish and Wildlife Service has proposed removing the American peregrine falcon from the endangered and threatened species list. After collecting and evaluating public comments, a final decision on delisting will be made within one year.
The restrictions placed on the use of DDT, the protection afforded by the Endangered Species Act, and the reintroduction of captive-bred chicks truly rescued the peregrine falcon from extinction. A cleaner environment and the success of cooperative recovery efforts provide great promise of a bright future for the peregrine falcon in North America.
Additional Resources:
White, C. M., N. J. Clum, T. J. Cade, and W. G. Hunt. 2002. Peregrine Falcon (Falco peregrinus). In The Birds of NorthAmerica. No. 660 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.
http://www.peregrine-foundation.ca
http://www.raptor.cvm.umn.edu/
http://www.peregrinefund.org |