The peregrine falcon is one of nature’s
swiftest and most beautiful birds of
prey. Long noted for its speed, grace,
and aerial skills, the peregrine is also
now a symbol of North America’s
recovering threatened and endangered
species.
Natural History
Peregrine falcons are crow-sized birds
with a wingspan of about 40 inches.
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 browner and darker
underneath.
The species is found almost worldwide,
mostly along mountain ranges, river
valleys, and coastlines. Three peregrine
subspecies exist in North America. The
Peale’s falcon (Falco peregrinus pealei),
is a year-round resident of the
northwest Pacific coast. The Arctic
peregrine (Falco peregrinus tundrius)
nests in the tundra of Alaska, Canada,
and Greenland, and typically winters as
far south as South America. The
American peregrine (Falco peregrinus
anatum) nests from central Alaska,
central Yukon Territory, and northern
Alberta and Saskatchewan, east to the
Maritimes, and south throughout
western Canada and the United States
to Baja California. American peregrine
falcons that nest in subarctic areas
generally winter in South America,
while those that nest at lower latitudes
usually don’t migrate as far.
Peregrine falcon nests (eyries) are
typically just scrapes or depressions dug
in gravel on a cliff ledge. Rarely, though,
peregrines will nest in a tree cavity or an
old stick nest. Some peregrines have
readily accepted manmade structures
such as skyscraper ledges, tall towers,
and bridges as urban equivalents of cliff
ledges. Peregrines vigorously defend
their nests, although they may abandon
them if harassed.
Courtship and territorial displays include
a high circling flight by the male and
dives and chases by both sexes. Females
lay clutches of three to five eggs and
incubate them for 32-34 days. During
incubation and when nestlings are very
young, the male hunts to feed the family;
when nestlings are older, both the male
and female hunt.
Peregrine falcon nestlings first fly at 39 to
49 days. They generally reach breeding
maturity at age 2, and may mate for life.
The longevity record for North American
peregrines is almost 17 years, but few
wild peregrines live this long.
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 Falcon
(Falco peregrinus)
U.S. Fish & Wildlife Service
International
Migratory Bird Day
(IMBD)
Set on the second Saturday in
May, IMBD is an invitation to
celebrate and support migratory
bird conservation.
Decline and Recovery
Peregrine falcons have never been very
abundant. In the 1930s and 1940s, there
were about 500 breeding pairs of
peregrine falcons in the East and about
1,000 in the West and in Mexico. Then,
beginning in the late 1940s, peregrine
falcon populations plummeted.
Scientists found unusually high
concentrations of the pesticide DDT and
its breakdown product DDE in birds of
prey, which accumulated DDT by feeding
on birds that had eaten contaminated
insects or seeds. DDE interfered with
eggshell formation, so eggs often had
shells so thin they broke during
incubation. Because reproduction was
poor, peregrine populations shrank
precipitously.
By the mid-1960s, American peregrines
had been practically eliminated east of
the Rocky Mountains and south of the
boreal forest in Canada. In the West,
peregrine populations were reduced by
80 to 90 percent by the mid-1970s. Only
the population of Peale’s peregrines
appeared stable.
In 1970, the American and Arctic
subspecies were listed as endangered.
The U.S. Fish & 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.
The Canadian Wildlife Service
took a similar action for peregrines
in Canada.
For the American peregrine falcon,
recovery plans included captive breeding
and release and/or relocations of wild
stock to re-establish breeding pairs in
areas where the species had been
extirpated. However, the most significant
action to aid peregrines probably was
the ban on most uses of DDT in Canada
and the U.S.
Following restrictions on the use of DDT
and other recovery efforts, Arctic
peregrine numbers increased to the
point that the subspecies was
reclassified in 1984 from endangered
to threatened. Then, in October
1994, the U.S. Fish & Wildlife
Service announced that the Arctic
peregrine falcon no longer
needed the protection of the
Endangered Species Act and
could safely be delisted.
There are now an estimated
2,000 to 5,000 breeding pairs in
North America.
Populations of peregrine falcons have
also recovered in the historical range of
the American subspecies. In 1998, there
were a minimum of 1,425 breeding pairs
of American peregrine falcons in the U.S.
and Canada, plus an additional 225
breeding pairs of mixed subspecies
heritage (associated with reintroductions
in the eastern U.S.), and an unknown
number of pairs in Mexico. In August
1999, the U.S. Fish & Wildlife Service
removed the American peregrine falcon
from the list of endangered and
threatened species, marking one of the
most dramatic success stories of the
Endangered Species Act.
Future Outlook
Though no longer listed under the U.S.
Endangered Species Act, the peregrine
falcon is still a protected species. The
Migratory Bird Treaty Act regulates the
take of peregrine falcons as well as all
other migratory birds in the U.S., while
the Convention on International Trade in
Endangered Species regulates the
international trade of peregrines because
peregrine subspecies are listed as
threatened, endangered, or otherwise at
risk in other countries. Moreover, state
laws and regulations protect peregrine
falcons, and may be more restrictive than
federal rules.
Peregrine falcon populations continue to
be monitored under the Endangered
Species Act. Because 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, depressed reproduction is still a
concern. Efforts are underway to reduce
use of this chemical in Mexico and other
Latin American countries.
Overall, a cleaner environment and the
success of cooperative recovery efforts
provide great promise of a bright future
for the peregrine falcon in North
America.
For more information on the recovery of
the 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
March 2000
