Field Guide/Birds/Falco peregrinus

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The Peregrine Falcon (Falco peregrinus) is a medium-sized falcon about the size of a large crow: 38-53 cm (15 to 21 inches) long. It has a wingspan of about 1 metre (40 inches). Males weigh 570-710 grams; the noticeably larger females weigh 910-1190 grams.

Introduction

Adult peregrine falcons have slate blue-grey wings and backs barred with black. Their undersides are white with light brown stripes. They have white faces with a black stripe on each cheek, and the head is blue-black. The subspecies vary in plumage; for instance immature males in the tundra have pale crowns, while birds of the northwestern coast of North America are darker than others. The younger birds are darker below, browner, and streaked rather than barred. All peregrines have large dark eyes.

The call of this bird is a harsh repeated "cack."

Peregrines eat mostly other birds such as pigeons, shorebirds, starlings, songbirds, parrots, and ducks. They attack their prey by flying high and diving ("stooping") at the victims.

The peregrine falcon is the fastest animal on earth. Although its level flight is no faster than that of many other birds, its diving speed is significantly greater; estimates range from 188 km/h[1] (117 Mi/h) to over 320 km/h (200 Mi/h).

These birds are greatly prized in falconry, where the hen is known as a falcon and the cock as a tiercel.

The bird's Latin name, peregrinus, means "foreigner" or "traveller". This is because wintering birds often wander far from their frequently bleak breeding areas.

Range, habitat, and nesting

Peregrine falcons live mostly along mountain ranges, river valleys, and coastlines and increasingly, in cities. They are widespread throughout the entire world and be found on all continents except Antarctica.

In North America, peregrine falcons still breed in the Rocky Mountains, the Pacific Northwest, and the Arctic tundra, as well as the Midwest states. They used to be commonly found in parts of the Appalachian Mountains and nearby valleys from New England south to Georgia, the upper Mississippi River valley, and along the Pacific coast as far south as Mexico.

Courtship displays include spectacular aerobatic flight and dives by the male and aerial pursuits. A pair may mate for life. These birds aggressively defend the nesting area.

The nest is a scrape or depression dug in gravel on a cliff ledge. Sometimes if no cliff is available, peregrines will nest in a tree cavity, an old stick nest, or even a tussock of grass on the tundra. These birds also nest on tall buildings in cities, which resemble their natural nesting sites. The female usually lays 3 to 5 eggs; the color ranges from reddish white to mottled brown.

If a peregrine falcon lives through its first year, it can live up to 10 years. However, most young birds do not survive their first year.

Peregrines on the northwest coast of North America and other mild-winter regions are usually permanent residents. Other populations migrate; for instance, birds from Alaska, northern Canada and Greenland migrate to Central and South America. Migrating birds may travel far out over open ocean.

Similarly, many birds from northern Eurasia move further south in winter, but in areas with less cold winters birds, especially adult males, will remain on the breeding territory.

Threats

The peregrine falcon became endangered because of the overuse of pesticides, in particular DDT, during the 1950s and 1960s. Pesticide build-up interfered with reproduction, thinning eggshells and severely restricting the ability of birds to reproduce. In several parts of the world, including eastern North America, the peregrine falcon was wiped out by pesticides. In 1970, the peregrine falcon was included in the US endangered species list.

Peregrine eggs and chicks are often targeted by thieves and collectors, so the location of their nest should not be revealed, unless they are protected.

Recovery efforts

File:Stamp-ctc-1990s-recovering-species.png
Successful efforts at saving endangered species like the Peregrine were recognised by a U.S. postal stamp.

Wildlife services around the world organised Peregrine falcon recovery teams to breed them in captivity, at Cornell University and the renowned World Center for Birds of Prey located in Boise, Idaho, among other places.

The birds were fed through a chute so they could not see the human trainers. Then, when they were old enough, the box was opened. This allowed the bird to test its wings. As the bird got stronger, the food was reduced because the bird could hunt its own food. This procedure is called hacking. To release a captive-bred falcon, the bird was placed in a special box at the top of a tower or cliff ledge.

Worldwide recovery efforts have been remarkably successful. In the United States, the banning of DDT, over time, made it possible for released birds to breed successfully. There are now dozens of breeding pairs of peregrine falcons in the northeastern USA. Many have settled in large cities, including New York, where they nest on skyscraper window ledges and the towers of suspension bridges. These structures typically closely resemble the natural elevated cliff ledges which the species prefers for nesting locations. During daytime the falcons have been observed swooping down to catch common city birds such as pigeons and starlings. In many cities, the falcons have been credited with controlling the numbers of such birds, which have often become pests, without resort to more controversial methods such as poisoning or hunting.

In Virginia, state officials working with students from the College of William and Mary in Williamsburg successfully established nesting boxes high atop the George P. Coleman Memorial Bridge on the York River, the Benjamin Harrison Memorial Bridge and Varina-Enon Bridge on the James River, and at other similar locations. 13 new chicks were hatched in this Virginia program during a recent year. The peregrine falcon was removed from the U.S. Threatened and Endangered Species list on August 25, 1999. Although still on the North Carolina Endangered Species list, the falcon seems to be making a comeback in western Northern Carolina, namely the Chimney Rock Park, which huge rock faces serve as ideal nesting ledges for the peregrine falcon. Attempts to set up nests for the birds have proved successful, but the birds always seemed to disappear or move further west. But in April 2005, bird watchers and a local ornithologist spotted a peregrine falcon defending its nest site.

In the UK, there has been a good recovery of populations since the crash of the 1960s. This has been greatly assisted by conservation and protection work led by the RSPB. Peregrines now breed in many mountainous and coastal area especially in the west and north. They are also using some city buildings for nesting, capitalising on the urban pigeon populations for food.

See also

Barbary Falcon, Falco (peregrinus) pelegrinoides, which is often considered to be a subspecies of the peregrine.

External links

bg:Сокол скитник da:Vandrefalk de:Wanderfalke es:Halcón peregrino eo:Migra falko ja:ハヤブサ nl:slechtvalk pl:Sokół wędrowny fi:Muuttohaukka sv:Pilgrimsfalk

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