Get Outdoors - Birds & Wildlife: Peregrine Falcon <i>(Falco peregrinus)</i>

The peregrine falcon is one of nature'sswiftest and most beautiful birds ofprey. Long noted for its speed, grace,and aerial skills, the peregrine is alsonow a symbol of North America'srecovering threatened and endangeredspecies.

Natural History

Peregrine falcons are crow-sized birdswith a wingspan of about 40 inches.Adults have slate blue-gray wings andbacks barred with black; pale undersides;white faces with a black stripe on eachcheek; and large, dark eyes. Youngerbirds are browner and darkerunderneath.

The species is found almost worldwide,mostly along mountain ranges, rivervalleys, and coastlines. Three peregrinesubspecies exist in North America. ThePeale's falcon (Falco peregrinus pealei)is a year-round resident of thenorthwest Pacific coast. The Arcticperegrine (Falco peregrinus tundrius)nests in the tundra of Alaska, Canada,and Greenland, and typically winters asfar south as South America. TheAmerican peregrine (Falco peregrinusanatum) nests from central Alaska,central Yukon Territory, and northernAlberta and Saskatchewan, east to theMaritimes, and south throughoutwestern Canada and the United Statesto Baja California. American peregrinefalcons that nest in subarctic areasgenerally winter in South America,while those that nest at lower latitudesusually don't migrate as far.

Peregrine falcon nests (eyries) aretypically just scrapes or depressions dugin gravel on a cliff ledge. Rarely, though,peregrines will nest in a tree cavity or anold stick nest. Some peregrines havereadily accepted manmade structuressuch as skyscraper ledges, tall towers,and bridges as urban equivalents of cliffledges. Peregrines vigorously defendtheir nests, although they may abandonthem if harassed.

Courtship and territorial displays includea high circling flight by the male anddives and chases by both sexes. Femaleslay clutches of three to five eggs andincubate them for 32-34 days. Duringincubation and when nestlings are veryyoung, the male hunts to feed the family;when nestlings are older, both the maleand female hunt.

Peregrine falcon nestlings first fly at 39 to49 days. They generally reach breedingmaturity at age 2, and may mate for life.The longevity record for North Americanperegrines is almost 17 years, but fewwild peregrines live this long.Peregrine falcons feed primarily on otherbirds, such as songbirds, shorebirds,ducks, and - in urban areas - starlingsand pigeons. Flying high above theirintended prey, peregrines will "stoop" ordive and strike in mid-air, killing the preywith a sharp blow. Scientists estimate thespeed of a diving peregrine to be morethan 200 miles per hour.

Decline and Recovery

Peregrine falcons have never been veryabundant. In the 1930s and 1940s, therewere about 500 breeding pairs ofperegrine falcons in the East and about1,000 in the West and in Mexico. Then,beginning in the late 1940s, peregrinefalcon populations plummeted.Scientists found unusually highconcentrations of the pesticide DDT andits breakdown product DDE in birds ofprey, which accumulated DDT by feedingon birds that had eaten contaminatedinsects or seeds. DDE interfered witheggshell formation, so eggs often hadshells so thin they broke duringincubation. Because reproduction waspoor, peregrine populations shrankprecipitously.

By the mid-1960s, American peregrineshad been practically eliminated east ofthe Rocky Mountains and south of theboreal forest in Canada. In the West,peregrine populations were reduced by80 to 90 percent by the mid-1970s. Onlythe population of Peale's peregrinesappeared stable.

In 1970, the American and Arcticsubspecies were listed as endangered. The U.S. Fish & Wildlife Serviceestablished peregrine falcon recoveryteams comprised of federal, state,and independent biologists torecommend actions necessary torestore peregrines in the U.S.The Canadian Wildlife Servicetook a similar action for peregrinesin Canada.

For the American peregrine falcon,recovery plans included captive breedingand release and/or relocations of wildstock to re-establish breeding pairs inareas where the species had beenextirpated. However, the most significantaction to aid peregrines probably wasthe ban on most uses of DDT in Canadaand the U.S.

Following restrictions on the use of DDTand other recovery efforts, Arcticperegrine numbers increased to thepoint that the subspecies wasreclassified in 1984 from endangeredto threatened. Then, in October1994, the U.S. Fish & WildlifeService announced that the Arcticperegrine falcon no longerneeded the protection of theEndangered Species Act andcould safely be delisted.There are now an estimated2,000 to 5,000 breeding pairs inNorth America.

Populations of peregrine falcons havealso recovered in the historical range ofthe American subspecies. In 1998, therewere a minimum of 1,425 breeding pairsof American peregrine falcons in the U.S.and Canada, plus an additional 225breeding pairs of mixed subspeciesheritage (associated with reintroductionsin the eastern U.S.), and an unknownnumber of pairs in Mexico. In August1999, the U.S. Fish & Wildlife Serviceremoved the American peregrine falconfrom the list of endangered andthreatened species, marking one of themost dramatic success stories of theEndangered Species Act.

Future Outlook

Though no longer listed under the U.S.Endangered Species Act, the peregrinefalcon is still a protected species. TheMigratory Bird Treaty Act regulates thetake of peregrine falcons as well as allother migratory birds in the U.S., whilethe Convention on International Trade inEndangered Species regulates theinternational trade of peregrines becauseperegrine subspecies are listed asthreatened, endangered, or otherwise atrisk in other countries. Moreover, statelaws and regulations protect peregrinefalcons, and may be more restrictive thanfederal rules.

Peregrine falcon populations continue tobe monitored under the EndangeredSpecies Act. Because DDE residues arestill found in some areas of the country,and DDT continues to be used in manyLatin American countries where someperegrines and their prey spend thewinter, depressed reproduction is still aconcern. Efforts are underway to reduceuse of this chemical in Mexico and otherLatin American countries.

Overall, a cleaner environment and thesuccess of cooperative recovery effortsprovide great promise of a bright futurefor the peregrine falcon in NorthAmerica.

For more information on the recovery ofthe peregrine falcon, visit http://endangered.fws.gov/peregrin.html.

For more information, contact:
U.S. Fish & Wildlife Service
Office of Migratory Bird Management
IMBD Events and Information Coordinator
703/358-2318
IMBD@fws.gov