01. Chickadee Notes

The Peregrine Falcon in New Brunswick


Peregrine Falcon

The eastern North American race of the Peregrine Falcon, Falco peregrinus anatum, is considered endangered throughout its range and in New Brunswick has been protected by the Endangered Species Act since 1976. This falcon has never been a common breeding bird in New Brunswick. Until the last century the Peregrine Falcon bred on the high sea cliffs of Grand Manan and the upper Bay of Fundy. Regrettably, the species was intentionally extirpated on Grand Manan during the 1920s. However, by 1938, breeding activity had resumed there and nesting continued until 1948. The species certainly disappeared as a breeder after 1960, mainly as the result of reduced breeding success triggered by pesticide contamination. The five nesting pairs that have been recorded in New Brunswick since 1989 result largely from the ten-year release of captive raised young by the Canadian Wildlife Service and Parks Canada. This is part of a North American-wide program that was started in the Atlantic region in 1982 and continues with the monitoring of nest sites.

Natural History

Falcons are noted for their quick, powerful wing strokes in flight. A distinct hooked bill and large, taloned feet distinguish these birds as predators. The Peregrine Falcon is a crow-sized bird, although the female is approximately one-third larger than the male. The anatum subspecies of the Peregrine Falcon characteristically has the thickest "moustache" mark of the three subspecies found in Canada. The adult has white to tawny underparts that are barred on the chest, belly and flanks, while the upper parts are slate blue. Immature birds have a streaked breast and dark brown upper parts.

Generally these birds choose cliffs for nesting sites...

The Peregrine Falcon is noted for its skill and agility as a hunter. Speed, size, and keen eyesight enable this falcon to capture various species of small and moderate-sized birds, which comprise the mainstay of the diet. Prey is usually pursued in non-forested areas such as shores, marshes and open river valleys. The method of attack is spectacular. The Peregrine will soar to a great height, launch a dive at prey that may reach a speed of over 350 km an hour, and then deliver a devastating blow to a victim with a half-closed foot. In the event that its kill is too heavy to carry, it will simply be dropped to the ground, where the falcon will land to devour it.

The anatum subspecies of the Peregrine has a preference for open country near coastal and inland cliffs. It is not uncommon for Peregrine Falcons to fly as much as 30 km from the nest site to hunt. Generally, these birds choose cliffs for nesting sites, but may also nest on man-made structures such as office towers and bridges. Widely reported is the fascinating account of the famous "Sun Life Falcon", a female that first visited the 20th floor of the Montreal headquarters of the Sun Life building in 1937. This bird returned to the site for 16 breeding seasons, had three successive mates, and fledged 21 young. Although other city nestings have occurred in Edmonton, Calgary, Winnipeg, and Saint John, none can match the "Sun Life Falcon" for sheer tenacity and productivity. The Saint John nesting was widely reported in 1989 when local bird watchers discovered a nesting pair using the bridge that spans the city harbour. Young have been successfully fledged from the bridge every year since then.

Both male and female incubate the three to four eggs...

During the breeding season, Peregrine Falcons are territorial and nests are usually at least 1 km apart. Such behaviour helps ensure that there will be adequate food for all nesting pairs and their young. The female prepares a nest by simply scraping a shallow hollow in loose soil, sand, gravel or dead vegetation on a cliff ledge, usually with a southerly exposure and under an overhang. Both male and female incubate the three or four eggs for about 32 days before hatching. When the young first emerge they have disproportionately large, pale gray feet. Their first down is sparse, shortand creamy-white. The nestlings will later acquire a second down that will be long and woolly, buffish-gray above and creamy below. At about four weeks the young will be feathered, but adult plumage will not appear for up to 45 days.

The males usually make their first attempts at flight a few days ahead of the females. Following fledging, the parent birds begin teaching their offspring to hunt. With prey in its talons, a parent will fly past, tempting a young bird to snatch the food from the adult in mid-air. This period of instruction may last several weeks, after which the young falcons will be ready to hunt on their own.

DDT an organochlorine pesticide, has been identified as the main cause of the decline of this species.

The Peregrine Falcon experienced a severe and rapid decline throughout eastern North America after 1950. DDT, an organochlorine pesticide, has been identified as the main cause of the decline of this species. The consumption of prey tainted with these chemicals led to a buildup of residues in body tissues. Although the amounts did not kill adult birds, eggs produced had thin shells and were subject to breakage, hence reduced nesting success and eventual population decline. It is also likely that shooting and other human activities, including disturbance at nesting sites, contributed to the dramatic decline of the anatum subspecies of Peregrine. Since the early 1980s, and following the North American ban on the use of DDT, Peregrine Falcon populations on this continent have stabilized or increased, in one case to former numbers. Unfortunately this pesticide is still in use in some countries where North American bred falcons winter.

In New Brunswick Peregrine migration peaks during the first two weeks of May and the first two weeks of October...

The name Peregrine is derived from Latin and means wanderer or migrator, and this falcon has one of the most extensive ranges of any bird in the world. In New Brunswick, the Peregrine Falcon has been observed throughout the province, but is most frequently seen along the lower Saint John River valley, the Fundy coast and Grand Manan. In New Brunswick Peregrine migration peaks during the first two weeks of May and the first two weeks of October, with birds moving largely along coastal areas and large river valleys. Most of these migrant birds belong to populations which nest north of New Brunswick. Some of these birds will travel as far as Central and South America to winter. New Brunswick nesters return to the province during the latter part of March or early April. By mid-April breeding pairs are usually together on territory and by mid-May the female has produced eggs and started incubation. Very rarely Peregrines may also reside in New Brunswick throughout the year. One or both of the breeding pair in Saint John has found an ample food supply among city pigeons and starlings and may be observed year round.

Helping Out

Although Peregrine populations have started to recover, the bird is still considered endangered over much of its range. There are several things we can do to ensure that the recovery continues. Never disturb nesting birds or the habitat close to traditional nesting sites. If you hunt gamebirds, be sure that you have correctly identified your target before shooting. Remember that all birds of prey are protected in New Brunswick. Avoid "predator prejudice" and remember that birds of prey are a natural part of ecosystems. Although the use of DDT is now banned in North America, other pesticides in use do pose a threat to birds of prey. Take some time to investigate alternative methods of pest control. Limit or eliminate your use of pesticides wherever you can.

Further Reading

Burnett, J. A., and Dauphine Jr., C. T., and McCrindle, S. H., and Mosquin, T. 1989. On The Brink: Endangered species of Canada. Environment Canada and Western Producer Prairie Books, Saskatoon. 192 pp.

Cade, T.J., 1982. The falcons of the world. Cornell University Press, Ithaca, New York. 192 pp.

Erskine, A.J., 1992. Atlas of the breeding birds of the Maritime Provinces. Nimbus Publishing and the Nova Scotia Museum, Halifax, Nova Scotia. 270 pp.

Godfrey, W. E., 1986. The birds of Canada, National Museum of Natural Sciences, Ottawa. 595 pp.

Martin, M., 1978. Status report on Peregrine Falcon, Falco peregrinus in Canada. Committee on the status of Endangered Wildlife in Canada, Ottawa. 45 pp.

Squires, W.A., 1976. The birds of New Brunswick. New Brunswick Museum Monographic Series No. 7, Saint John, N.B. 221 pp.