Peregrine Falcon 

(Falco peregrinus) 

The peregrine falcon is 

one of nature’s swiftest 

and most beautiful 

birds of prey. Its name 

comes from the Latin 

word peregrinus, 

meaning “foreigner” 

or “traveler.” This 

impressive bird has 

long been noted for its 

speed, grace, and 

aerial skills. Now, it is 

also a symbol of 

America’s recovering 

threatened and 

endangered species.

Three subspecies of the peregrine falcon 

inhabit North America: the American (Falco 

peregrinus anatum), Arctic (Falco peregrinus 

tundrius), and Peale’s (Falco peregrinus 

pealei). Peregrine falcons are roughly crowsized—about 15 to 21 inches long—with a 

wingspan of about 40 inches. As with many 

raptors, or birds of prey, females are larger than 

males. Adults have slate blue-gray wings and 

backs barred with black; pale undersides; white 

faces with a black stripe on each cheek; and 

large, dark eyes. Younger birds are darker 

below and browner. 

Peregrine falcons live mostly along mountain 

ranges, river valleys, and coastlines. 

Historically, they were most common in parts 

of the Appalachian Mountains and nearby 

valleys from New England south to Georgia, 

the upper Mississippi River Valley, and the 

Rocky Mountains. Peregrines also inhabited 

Pacific Coast from Mexico north to Alaska and 

in the Arctic tundra. 

The peregrine falcon also is found in other 

parts of the world. Most peregrines from 

northern Alaska, Canada, and Greenland 

migrate in the fall to Central and South 

America. On the way, they often hunt along the 

barrier islands on the Atlantic and Gulf of 
Mexico coasts. Peregrines that nest south of 

Canada migrate lesser distances, and some do 

not migrate at all. 

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 nest is a scrape or depression dug in gravel 

on a cliff ledge. Rarely, peregrines will nest in 

a tree cavity or an old stick nest. Many 

peregrines readily nest on manmade structures, 

including skyscraper ledges, tall towers, and 

bridges, the urban equivalents of cliff ledges. 

Peregrine falcons 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. Scientists estimate the 

speed of a diving peregrine to be more than 200 

miles per hour. 

Peregrine falcons have never been very 

abundant. Studies in the 1930s and 1940s 

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 1940s, 

peregrine falcons suffered a devastating and 

rapid decline. By the mid-1960s, 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-1970s. 

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. Peale’s peregrines were never 

listed because they continued to breed at near 

normal levels and had only traces of DDT. 

DDT and other pesticides were not used where 

Peale’s peregrines live, and since Peale’s do 

not migrate and feed largely on non-migratory 

prey, they were not likely to pick up DDT 

applied elsewhere. 

In 1972, under the authorities granted by the 

Federal Insecticide, Fungicide, and 

Rodenticide Act (FIFRA), the Environmental 

Protection Agency (EPA) banned DDT for 

most uses in the U.S. However, DDE residues 

are still found in some areas of the country. 

DDT is gradually being phased out in many 

Latin American countries where some 

peregrines and prey spend the winter. 

The U.S. Fish and Wildlife Service established 

peregrine falcon recovery teams composed 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 U.S. 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 

American peregrines have been released since 

1974. Large-scale reintroductions of peregrines 

have ceased due to the peregrine’s recovery, 

and relatively few reintroductions are still 

taking place in the United States. 

To release captive-bred peregrines, young 

birds are placed in specially equipped boxes 

on top of a manmade tower or cliff ledge. At 

first, the birds are fed through a chute so they 

cannot see their human benefactors. When 

they are old enough, the box is opened and the 

young peregrines begin testing their wings. 

Their food is gradually reduced as the young 

falcons learn to hunt on their own. This 

process is known as “hacking.” 

Arctic peregrine falcons declined by as much as 

80 percent; however, enough survived the 

impacts of pesticides that releases of captivebred young were not necessary. Following 

EPA’s restrictions on the use of DDT and 

recovery efforts under the Endangered Species 

Act, Arctic peregrine numbers increased to the 

point that the subspecies was reclassified in 

1984 from endangered to the less critical 

category of threatened. Then, in October 1994, 

the U.S. Fish and Wildlife Service announced 

that the Arctic peregrine falcon had increased 

in numbers to the point that this subspecies no 

longer needed Endangered Species Act 

protection and could safely be removed from 

the threatened and endangered species list. 

There are now thousands of Arctic peregrines 

in North America. 

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. Postdelisting monitoring occurred in 2003, is being 

carried out in 2006, and will continue in 2009, 

2012, and 2015. Results from 2003 show the 

population continuing to climb, and was 

estimated at about 3,000 breeding pairs in the 

U.S., Canada, and Mexico. Territory 

occupancy, nest success, and productivity were 

all at levels considered normal for healthy 

peregrine falcon populations. 

The protection afforded by the Endangered 

Species Act, EPA’s use of their authorities 

under FIFRA to severely restrict the use of 

DDT, and the reintroduction of captive-bred 

chicks have rescued the peregrine falcon from 

extinction. A cleaner environment and the 

success of cooperative recovery efforts with 

out partners provide great promise of a bright 

future for the peregrine falcon in North 

America. The Service, with the indispensable 

help of partner agencies, other organizations, 

and volunteers, is dedicated to assuring that 

future through coordinated population 

monitoring at least through 2015. 

U.S. Fish & Wildlife Service 

1 800/344 WILD 

http://www.fws.gov 

May 2006