AMERICAN
PEREGRINE FALCON
Falco
peregrinus anatum
Peregrine falcon in flight
©
Glenn Nevill
The American peregrine falcon
can be seen soaring high in the sky throughout the Los Padres
National Forest. These magnificent birds have wingspans up to
44in (almost 4 feet!) and fly at speeds up to 60 mph. When
diving down (a.k.a, “stooping”) for their prey, they can top
speeds of over 200 mph, making them the fastest animal that
inhabits the Los Padres. They are very efficient predators. By
using their large talons, they are able to masterfully grab
and/or strike their prey in mid-air, then use their unique
notched beak to bite through the neck to kill it. They do enjoy
a challenge though, because their prey consists of other
highly-mobile birds and sometimes bats.
There are 18 subspecies of
peregrine falcon, which together have a global distribution,
occurring on all continents except Antarctica. The subspecies of
American peregrine falcon inhabits North America, from Mexico to
Canada. Although some American Peregrine falcons will migrate,
falcons in California tend to remain in the same region
year-around. Historically, they occurred throughout California
but are now mainly located in the central and southern coast.
Their population is expanding though, with hopes of the
historical range being fully restored.
American peregrine falcons
begin their breeding season in February, which lasts through
June. During this season, the males will become territorial and
highly protective of their nest sites. The females normally lay
four eggs, typically in March. Both the male and female help
keep the eggs warm and healthy by incubating them for 29–33
days. In California, fledging occurs in late May or early June.
Juveniles will start hunting on their own and claim their
independence about 6–15 weeks later.
The Los Padres National Forest
contains the peregrine falcon's woodland, forest, and coastal
habitats. Here they enjoy the “high life” by nesting upon ledges
and small caves of high vertical cliffs. They usually nest
around 4,000 ft. elevation but have been found at upwards of
10,000 ft. elevation. Occasionally they nest in trees and tall
buildings as well. They especially enjoy homes with a view,
particularly a panoramic view of open country which contains an
abundance of the other birds that they prey upon.
Threats and Conservation
Prior to the 1940s, the
American peregrine falcon was estimated to have over 3,875
nesting pairs throughout North America. However, the populations
of peregrine falcons and other top predators began quickly
declining through the middle part of the century. By the early
1970s, no more than 5-10 pairs remained in California. Their
decline is attributed to synthetic organochlorine pesticides
(especially the commonly known one, DDT). DDT is not excretable,
meaning once ingested or exposed to it, it remains in fat tissue
and accumulates over time until it reaches lethal levels. DDT
reduced the amount of calcium in peregrines falcons’ eggshells,
making them thin and prone to lose moisture and early cracking.
The result of DDT exposure was that fewer chicks were surviving
every year.
Photo
©
Adrian Ewart
Because
of steep declines, the American peregrine falcon was one of the
first species classified as "Endangered" under federal law in
1970 (before the modern-day Endangered Species Act). The use of
DDT was subsequently banned the United States in 1972.
Experimental captive-release programs (breeding falcons in
captivity then releasing them) proved successful at increasing
nesting pairs, with more than 6,000 falcons released since the
program started. The banning of DDT, coupled with these
captive-release programs, allowed the peregrine falcon to
repopulate its historic range. By 1998, it was estimated that
1,650 pairs were in North America, and the following year, the
peregrine falcon was removed from the federal endangered species
list. The American peregrine falcon is one of the 22 species
that have been delisted from the ESA because of successful
population recovery. It was delisted on August 25, 1999 and its
population is believed to still be growing. The U.S. Fish &
Wildlife Service will conduct population surveys every three
years and will consider placing the species back on the
endangered list if population declines are detected. There are
currently more than 3,000 peregrine falcon pairs in North
America, so the population is continuing to grow and is an
Endangered Species Act success story.
This species is still at risk
to illegal shooting, illegal falconry activities, and habitat
destruction. Because of these threats, the U.S. Forest Service
still considers the peregrine falcon to be a "Sensitive
Species," giving the bird added protection as it continues on
the path of recovery. The conservation measure of highest
concern on National Forest System lands is protecting
cliff-nesting sites from human disturbance, particularly during
the nesting season. Additionally, the protection of riparian
areas to maintain prey abundance is of importance to the falcon
too.
Photo ©
Avia Venefica
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