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American Peregrine Falcon
Falco peregrinus anatum
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Threats
Chemical pollution,
habitat encroachment
STATUS:
ESA -- ENDANGERED
(as subspecies anatum)
SIZE:
Length
15Ð21 inches (38Ð53 cm)
Wingspan:
44 inches (112 cm)
HABITAT:
Nests on cliffs, high
buildings and bridges
CURRENT RANGE:
Every continent (except Antarctica) plus coastal
and oceanic islands;
map shows ranges of all
N. American subspecies
CONSERVATION:
Captive-breeding and
release programs; protection of existing eyries; banning
of dangerous pesticides; Species Survival Plan
in effect; CITES
trade restrictions
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Nature's Dive Bombers
Streaking out of the sky in dives, or "stoops," of more than 200 miles per hour (320 km/h), peregrine falcons are among the most dramatic of all predators. Their weapons are sharp talons and blazing speed: they can reach 60 miles per hour (96 km/h) in level flight. A peregrine usually makes its kill in midair, diving from above and dispatching the prey with a blow from its feet. Peregrines most often hunt doves and pigeons but also eat waterfowl, shorebirds, songbirds, and even bats.
Devastation
As predators, peregrines are at the top of the food chain. This means they're especially vulnerable to chemicals and other human-introduced substances, particularly those that remain in the systems of prey
animals. The devastating effect of DDT on peregrine populations was one of our first clear indicators of the dangers of unchecked pesticide use. DDT was commonly used during World War II to kill lice and other pests infesting soldiers and civilians in war zones. After the war, it was used heavily along coastal areas and wetlands to control mosquitoes and other insects.
Animals that ate insects and plant materials in these areas ingested DDT. Once inside the body, DDT is not excretable; it stays in the fatty tissue. Every time a peregrine ate a bird that had ingested DDT, the falcon got a dose of the pesticide. DDT reduces the amount of calcium in the eggshells of female peregrines. The result: peregrines began laying thin-shelled eggs that were prone to lose moisture and crack before the chicks could hatch. Fewer and fewer chicks survived. By the mid-1960s, no breeding pairs of peregrines remained in the eastern U.S.
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During courtship, peregrines put on incredible displays of aerial acrobatics. They rise to great heights,
then fold their wings and streak down like missiles, pulling up at the last possible moment and soaring into a series
of upside-down loops.
Throughout the world,
numerous peregrine
falcon subspecies are considered Endangered
or Threatened. In North America, these include
the Arctic peregrine as well as the American peregrine.
During World War II, British airmen who crash-landed while on sea patrol along England's coasts conveyed their location to rescue units via carrier pigeon. Peregrine falcons, as hunters of pigeons, were a threat to this strategy. So in 1940, England's Secretary of State for
Air issued the Destruction of Peregrine Falcons Order. This made it legal, in certain parts of Britain, to kill peregrines and/or destroy their eggs. The order expired in 1946. According to one estimate, the effect of this order was to reduce the nesting population of peregrines in southern England by about half. Its effect on the airmen is unknown.
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Recovery
The recovery of the peregrine falcon in the eastern U.S. was the result of a highly successful program started by the Peregrine Fund at Cornell University. The Fund led the drive to cut back on, and ultimately ban, the use of DDT. A captive-breeding program was then begun, aimed at reintroducing the peregrine in the East. Following numerous breakthroughs in captive-breeding techniques, the program began releasing birds in the early 1970s. At this writing, some 3,000 peregrines have been released; nearly a quarter of the original peregrine population in the Northeast has been restored. Releases ended in New York State in 1988.
New York City is once again a popular peregrine habitat. Peregrines nest on many Wall Street skyscrapers, on Riverside Church, and on the Tappan Zee and Verrazano-Narrows Bridges. Pairs will usually return to the same nesting site for many years.
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