American peregrine falcon
Falco peregrinus anatum |
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Threats to Survival | What has been done?
Life History
 A medium-sized bird of prey, the adult American peregrine falcon (Falco peregrinus anatum) is
slate-grey on the head and back, barred and spotted below and has
distinctive black "sideburns." Like other falcons, the peregrine has long,
pointed wings and a slender tail. Immature peregrines have brown backs
with heavy dark streaks below. These birds acquire adult plumage in their
second year, but most do not reproduce until age of three.
Historically, the peregrine falcon ranged throughout North
America and much of the rest of the world. In the eastern United States
they nested from the Great Lakes and eastern Maine, south to Georgia and
Alabama. Numbers were never large because each pair requires a large
feeding territory centered around a suitable nesting site.
Peregrines usually nest on high, remote cliff ledges. The
smaller male arrives first and courts the female by performing acrobatic
aerial displays consisting of dives, loops and rolls. After courtship, the
nest site or "eyrie" is chosen by the female. It consists of a shallow
depression, or "scrape," in the rocks and soil, sometimes surrounded with
twigs and grass. Both members of a pair may return to the same cliff in
subsequent years but do not stay together after nesting.
In 1979 a bird, nesting on the 33rd floor of Baltimore's U.S. Fidelity and Guaranty building, caused much excitement.
The bird was a peregrine falcon named "Scarlett." Professional and amateur bird enthusiasts alike were ecstatic about this and monitored Scarlett's every move.
What was so captivating about this bird? Scarlett was an endangered species that had been hatched and raised in captivity and released into the wild. Of all the possible nest sites available, she and her mate had chosen the roof of this building in downtown Baltimore, Maryland.
Once settled into her new home, Scarlett laid infertile eggs. She was, however, given foster chicks to raise, the first peregrine falcon in the eastern United States to do so since 1959.
Learn more:
Peregrine falcon page on the US Fish & Wildlife Service's Endangered Species Website. |
In the Atlantic Flyway, nesting generally starts in late March and, within
a week, females lay three to five eggs. Eggs are pale rose with brown
blotches. Incubation lasts about 33-34 days. Females incubate the eggs
while males hunt and bring food to their mates. If the first clutch of
eggs is destroyed, a second clutch may be laid. Chicks stay in the eyrie
six to seven weeks after hatching and are brought food by both parents.
The peregrine falcon, often referred to as the duck hawk,
feeds primarily on birds. Shorebirds and other species such as blackbirds,
robins, jays and flickers are commonly taken. Prey range in size from
swallows to large ducks. In urban areas, starlings and pigeons are the
mainstay of their diet. Peregrines fly above their prey and, when ready to
strike, fold their wings and fall into a dive called a "stoop." Peregrines
in this free-fall may reach speeds of up to 200 miles per hour. Prey may
be taken over land or water, and often are caught in mid-flight. The
peregrine strikes larger birds with its strong feet, instantly killing or
stunning them. Small birds may be plucked from the air.
Threats to
Survival
Peregrine falcons have few natural threats and may live 15
years once they have learned to hunt. Predators such as raccoons and
great-horned owls occasionally take eggs or chicks from the nests. People
pose the greatest threat to this master of the air. Shooting, taking
of eggs and young, poisoning and habitat destruction all contributed to
the decline of peregrine falcons from much of their historic range.
Before World War II, the peregrine population in the
eastern United States was estimated at about 350-400 breeding pairs.
Indiscriminate shooting of peregrines was a key problem in the early
1900s. Falconers prized these birds for their excellent hunting ability
and often took chicks from nests to be trained in the ancient art of
falconry. Another problem was the taking of eggs by collectors.
During the late 1940s the numbers of nesting peregrines in
the East declined sharply and many eyries were deserted. Breeding attempts
were unsuccessful and many nesting cliffs were occupied by only one
individual. Egg collectors, falconers, predators and human disturbance
could not account for this abrupt decline.
After World War II, the use of a new insecticide, known as
DDT, increased. At the same time, populations of peregrines, eagles and
other raptors continued to decrease. Small birds and mammals ingested prey
contaminated with the pesticide. Raptors feeding on the contaminated birds
and rodents were, in turn, poisoned by a progressive build-up of the
pesticide in their bodies. DDT was especially harmful because it caused
eggshell-thinning and, therefore, reduced reproductive success. Even
though the adult birds survived, they could not produce offspring. By1964
nesting peregrine falcons were extinct in the eastern United States.
Peregrines still nesting in the western United States were determined to
be an endangered species in 1970, two years before DDT was finally banned
from use. Later all North American peregrines were listed as endangered or
threatened.
What Has Been Done?
Banning the use of DDT in the United States was a critical
step, but re-establishment of nesting peregrines called for new
techniques. In 1979, a Peregrine Recovery Plan was prepared. The objective
of this plan was to restore a new, self-sustaining population of about
175-200 breeding pairs of peregrine falcons in the eastern United States
through a captive propagation and release program. Peregrine falcons from
various sources were used as breeding stock. Chicks were hatched and
raised in captivity and then "hacked" into the wild. Hacking is a process where captive reared birds are released into the wild and provided with food, without the interaction
of adult falcons.
The Recovery Program has been very successful. The
Chesapeake Bay has again become an important area for resident nesting
peregrines and migrating peregrines from the tundra of North America. Some
of the released birds have taken up residence in cities or on bridges.
Here, the falcons can find an abundance of prey including pigeons,
waterfowl and shorebirds. In 1997 the eastern population of peregrine
falcons reached 174 pairs, from which the Chesapeake Bay region
contributed 27 confirmed pairs, producing 45 chicks. Recovery efforts
finally paid off. In 1998, the peregrine falcon was proposed for removal
from the endangered species list, and was delisted on August 20, 1999.
The captive breeding and release program has been
successful, but concerns remain. The peregrine falcon population will be
monitored for the next 15 years. In order to maintain a heathy population
of peregrines in the East, nesting and wintering habitat must be
preserved. Peregrines still need to be protected from killing or capture.
With help and support by the public, the peregrine falcon will continue to
be an awe inspiring sight on the Chesapeake Bay and the East
Coast.
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