The method used to increase falcon populations is the reintroduction of captive-reared chicks into the wild, a process termed "hacking." In hacking programs, selected adult birds are bred in captivity. The eggs are incubated and hatched in a laboratory. Chicks three to four weeks old are transferred to a location, called a hack site, where scientists hope to establish a new falcon territory. Once there, to prepare the chicks for release, they are kept several weeks in a protective wooden box with a view of the area.
Hack sites are staffed by trained specialists who carefully monitor, tend, and feed the chicks for approximately three weeks. Attendants observe only from a distance at this time. Food drops are made via a long, sloping tube, preventing the association of food with humans. When their wings are strong enough for flight, fledglings are released. The young falcons continue to eat at the hack site until they learn to hunt on their own.
PEREGRINES AT ACADIA
Adult peregrines often return to areas near their original hack sites, which was the case at Acadia. When an adult peregrine hacked in 1986 returned to the site in 1987, the park discontinued the hacking program for fear that this adult male would prey upon any released chicks.
The returning male came back again in 1988 and attracted a mate. He and his mate had their first successful nest in 1991, the first in Acadia in 35 years. Since that time, at least one pair and sometimes three other pairs have produced young in the park, bringing the total to 87 chicks.
Some of the young have been banded to learn about peregrine migration, habitat use, and longevity. Many variables are involved in allowing the researchers to band. The speed at which the chicks develop allows only a three-to-four-day window in which the researchers can band. The chicks must be large enough that the band does not fall off and not too large to attempt to fly without the proper flight feathers.
Falcon banding provides valuable information on the activity of the peregrines. It allows scientists to keep track of peregrine migration, movement, breeding activity, and longevity. Peregrines are known to travel very far for the winter, including South America, Costa Rica, and the Virgin Islands. Banding also allows park biologists to track where peregrines set up nesting sites.
Peregrine chicks born in the park have been found in several places:
Banding has allowed scientists to determine that peregrine falcons have a 50% survival rate in the first year. Only 25% of birds make it to age two. With such a high mortality rate, the park is proud to host successful nesting areas to help this falcon regain its status.
Each year, in early spring, park resource managers watch intently for signs of returning peregrines. (Visit the Peregrine Falcon Photo page to see pictures of banding during the 2006 season.) If mating or nesting behavior is observed, certain trails are temporarily closed to avoid disturbance to the nesting area. These measures are helping this magnificent falcon make a triumphant comeback in Acadia National Park, and contributing to the success story of the Endangered Species Act.
Feeding: Hunts most vigorously at dawn and dusk in open areas like shores, marshes, and valleys. Hunting is often accompanied by a series of sharp, aggressive, territorial calls, "kee, kee, kee, kee, kee—kee, kee, kee, kee, kee." Plucks feathers from the prey as it feeds.
Strikes: Usually in mid-air, knocking the quarry to the ground. Less commonly, it will strike and grab prey and fly away.
Nesting: Mostly on precipitous cliffs, but will also nest under suspension bridges and atop tall city buildings. Eggs are laid on a sand- or gravel-covered ledge with a depression that has been scratched in preparation for the clutch. This area is called a scrape.
March to Mid-April (courtship)
Mid-April though May (nesting)
July through August (fledging)
Fall and Winter (migration)
Wings: Long, pointed, sickle shaped. All falcons in a dive appear to have sickle-shaped wings. Wing shapes depend on the degree to which the bird is soaring or diving. Be careful in making identifications.
Head: Small with dark "sideburns"
Size: Crow-sized, female larger than male
Feet: Large (hence the nickname "big-footed falcon")
HELP PROMOTE THE CONSERVATION OF PEREGRINES