Gyrfalcon
Falco rusticolus
Morphology 3
The world's largest falcon is polymorphic, being recognized in three color phases: white, grey, and dark. The dark phase is dark grey, almost black, in some individuals and groups of this morph are found in northern Canada. This species is sexually dimorphic: Males weigh 800-1300g, averaging 53cm;21in length and females weigh 1400-2100g, averaging 56cm;22in length. The shape of the gyrfalcon is characteristically the same as most falcons; long pointed wings, long tail and a notched bill. Adults characteristically have yellow ceres, eye-rings and legs. This species may perhaps only be confused with the Northern Goshawk (Accipiter gentilis) which inhabits dense forests, or the Peregrine Falcon (Falco peregrinus) which is somewhat smaller with a dark slaty-blue-black "helmet" and a lighter underside (Wheeler and Clark 1995; Cade 1982).
Habitat 4
Primarily open country in the Arctic, including tundra, open coniferous forest, mountainous regions, and rocky seacoasts; generally in coastal areas in winter (AOU 1983, National Geographic Society 1983). Usually nests on cliff ledges, ideally beneath sheltering overhang; sometimes nests in trees or on man-made structures. Nest generally is a scrape on a rock ledge or an abandoned hawk or raven nest. May nest on same cliffs as does peregrine. May compete successfully with peregrine for nest sites. May change nest site in successive years.
Trophic strategy 5
Unlike eagles which use their large size to rob meals, and peregrine falcons which use gravity to gain tremendous speed, the gyrfalcon uses raw power to capture prey, usually in a tail chase. Usually low coursing flights are used in open habitat (no trees for concealment) where gyrfalcons will strike prey both in the air or on the ground . The majority of prey (by biomass) that consitutes the diet consists of ptarmigan (Lagopus sp.), Arctic ground squirrel (Spermophilus parryii) and Arctic hares (Lepus arcticus). Other prey includes other small mammals (mice and voles) as well as other birds (ducks, sparrows, buntings)
While hunting, this falcon uses keen eyesight to spot potential prey, as almost all animals in the north are cryptically colored to avoid detection. When potential prey is spotted a chase usually occurs where more than likely the prey will be knocked to the ground in a powerful blow from the talons and then pounced upon. Gyrfalcons are powerful enough to have sustained flight while hunting and occasionally wear their prey out until capture is easy. During nesting, the gyrfalcon will also cache meals with large prey such as Arctic hares between feedings. Rock doves (Columba livia), or pigeons as they are commonly known, although not native are preyed upon heavily in major centers by gyrfalcons during winter months (Lange and Dekker 1999; Stelfox and Fisher 1998; Cade 1982; Poole 1987).
Sources and Credits
- (c) Bill Gracey, some rights reserved (CC BY-NC-ND), https://www.flickr.com/photos/9422878@N08/15997983503/
- (c) gisela gerson lohman-braun, some rights reserved (CC BY-SA), https://www.flickr.com/photos/giselaglb/19522930321/
- Adapted by Yukon Conservation Data Centre from a work by (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/31394680
- Adapted by Yukon Conservation Data Centre from a work by (c) NatureServe, some rights reserved (CC BY-NC), http://eol.org/data_objects/28824444
- (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/31394684
More Info
Range Map
iNaturalist.ca Map
| Animal | Bird |
|---|---|
| Color | grey, white |
| Bird | raptor |
