Peregrine Falcons - Birds of Prey

Peregrine Falcon: Dive, Dive, Dive! (Blink of An Eye: Superfast Animals)
Peregrine falcons soaring back from the brink of extinction
Bay Naturalist / By Kathy Reshetiloff  - Bay Journal

In 1999, when the American peregrine falcon was removed from the list of endangered species, the bird’s recovery from near extinction in North America was hailed as a tremendous conservation success story. Today, the peregrine’s recovery continues at an impressive pace.

The U.S. Fish and Wildlife Service released the results from the first nationwide monitoring effort measuring the peregrine falcon’s recovery, which put the number of nesting pairs in North America at about 3,000—nearly 10 times the number estimated in 1970 when the bird was first protected as an endangered species and considerably more than the roughly 1,800 breeding pairs estimated in 1999, when the peregrine was declared recovered and de-listed.

In 2003, the first year of post-delisting monitoring, more than 300 observers—many representatives from the same partners who supported the recovery effort—monitored 438 peregrine falcon territories across six regions. Surveyed areas included the Northeast/Great Lakes, Southeast, Southwest, Rocky Mountains, Pacific and Alaska.

A second round of monitoring was done this year, and preliminary results indicate that the peregrine population continues to grow. Final results and analyses from 2006 will be published in a report in the summer of 2007. Monitoring will continue in 2009, 2012 and 2015. The monitoring of contaminant levels in eggs and feathers will be reported in the future as well.

A medium-size bird of prey, an adult peregrine falcon is slate gray on the head and back, barred and spotted on the underside, 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.

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.

The peregrine falcon feeds primarily on other birds. Shorebirds, blackbirds, robins, jays and flickers are commonly taken. Prey ranges in size from swallows to large ducks.

After World War II, the use of new insecticides known as chlorinated hydrocarbons increased. Simultaneously, the populations of peregrines, bald eagles, and other birds of prey began to decrease. Small birds and mammals ate invertebrates contaminated with pesticides. Eagles and falcons feeding on contaminated birds and rodents were, in turn, poisoned by the progressive buildup of pesticides in their body tissue.

DDT, a widely used pesticide, was especially harmful because it caused eggshell thinning and, therefore, reduced reproductive success. Although adult birds survived, they could not produce offspring.

By 1964, nesting peregrines were extinct in the eastern United States. Peregrines still nesting in the western part of the country were listed as endangered in 1970, two years before DDT was finally banned from use.

During the recovery effort, more than 6,000 peregrine falcons were released into the wild by government and private raptor specialists.

Some of the reintroductions took place in urban areas after researchers discovered that the falcons can successfully adapt to nesting on skyscrapers and other urban structures, where the abundant pigeons and starlings are the mainstay of their diets. In the Northeast and Midwest, two-thirds of peregrine falcons nest on man-made structures.

In addition to the DDT ban, the recovery of the peregrine falcon has been credited to protections afforded by the Endangered Species Act. Combined efforts of the federal and state wildlife agencies, universities, private organizations and falcon enthusiasts greatly accelerated captive breeding programs, reintroduction efforts and the protection of nest sites during the breeding season.

Similar efforts took place in Canada.

Kathryn Reshetiloff is with the U.S. Fish and Wildlife Service’s Chesapeake Bay Field Office in Annapolis.

Peregrine falcons soaring back from the brink of extinction
Article from Bay Journal - Jan 2007

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