The Gyrfalcon breeds in arctic and alpine tundra in northern Canada and Alaska, in areas with abundant ptarmigan or near colonies of nesting seabirds or waterfowl. Habitats include rocky seacoasts, offshore islands, barren lands with rocky outcrops, river bluffs, lake bluffs, and mountainous terrain up to more than 5,000 feet in elevation. The low vegetation in their habitat includes species of sedge, cottongrass, lichen, moss, willow, and birch. They sometimes venture into margins of boreal forest or small stands of spruce along beaches or dunes. In winter they probably vacate the highest latitudes and elevations, and may range as far south as the northern United States. There they are usually found in open areas below 3,000 feet in elevation with abundant birds for prey, including coasts, reservoirs, farmland, grasslands, shrublands, and river valleys.Back to top
Gyrfalcons rely heavily on Willow Ptarmigan and Rock Ptarmigan but also hunt other birds, including seabirds, waterfowl, shorebirds and songbirds. They have been known to capture sage-grouse, jaegers, gulls, terns, fulmars, alcids, pheasants, hawks, owls, falcons, ravens, crows, magpies, redpolls, Savannah Sparrows, Lapland Longspurs, and Snow Buntings. They may also hunt mammals such as hares, ground squirrels, lemmings, and young arctic fox. The Gyrfalcon spots prey from a high perch or on the wing. It makes most of its captures by striking prey and driving it to the ground rather than grasping it in the air; the prey usually ends up with a broken breastbone. The Gyrfalcon may fly low and sneak up on its victims, chase prey over a long distance to tire it out, or hover and dive. Females often cache food temporarily during the breeding season, storing it behind vegetation within several hundred feet of the nest site.Back to top
Gyrfalcons nest on cliffs or in conifer tree nests of other species, such as Common Ravens and Golden Eagles. They may nest directly on cliff ledges, often protected by overhangs oriented away from the wind. Both males and females visit nesting cliffs before beginning to breed; the males outnumber the females and advertise for mates.
The nest ranges from bare or debris-covered soil to a structure of dead sticks, usually with little or no lining. Although Gyrfalcons do not build nests themselves, both the male and the female contribute to scraping a hollow depression in the center.
|Clutch Size:||1-5 eggs|
|Egg Length:||2.2-2.4 in (5.6-6.2 cm)|
|Egg Width:||1.7-1.9 in (4.3-4.8 cm)|
|Incubation Period:||34-36 days|
|Nestling Period:||45-50 days|
|Egg Description:||Ranging from white to reddish brown, with variable cinnamon spots.|
|Condition at Hatching:||Covered with thick down, with eyes open; capable of sitting up and begging shortly after hatching.|
Gyrfalcons usually spend the whole year alone or in pairs, and they appear to mate for life. The male performs spectacular aerial displays with dives and rolls. Around the pair’s cliffside nest they defend a territory nearly a mile wide, usually spaced between 3 and 60 miles from the nearest pair. They call aggressively to maintain the territory, and both the male and female may chase and strike at intruders—including Common Ravens, Rough-legged Hawks, and Peregrine Falcons—during breeding or nonbreeding season. They may also lock talons with intruders; sometimes two combatants strike the ground still locked together. Gyrfalcons may be mobbed by small songbirds. They are capable of very fast flight, and may reach speeds of 130 miles per hour when stooping for prey. They sometimes run or hop onto rocks to chase prey.Back to top
Gyrfalcons show no evidence of long-term population changes in North America. Partners in Flight estimates the global breeding population at 70,000 individuals, with 43% spending part of the year in Canada, and 11% ranging into the U.S. during the winter. This is a U.S.-Canada Stewardship species and rates a 9 out of 20 on the Continental Concern Score. The species is not on the 2016 State of North America's Birds' Watch List, and are not being actively managed. However, there has been controversy about the effect of their use in falconry in other parts of the world. Declines in Scandinavia and the vicinity have been attributed to falconry, habitat modification, and egg collection. Other threats include shooting in Iceland and accidental capture by ptarmigan traps or fox traps in Russia. The remote breeding range of North American Gyrfalcons has kept them safe from such threats, though human disturbance does sometimes deter them from returning to nest sites in later years. The most significant current threat is climate change, which has begun to transform the landscape within their range.Back to top
Booms, Travis L., Tom J. Cade and Nancy J. Clum. 2008. Gyrfalcon (Falco rusticolus), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.
Crossley, Richard, Jerry Liguori and Brian Sullivan. 2013. The Crossley ID Guide: Raptors: Princeton University Press.
Lutmerding, J. A. and A. S. Love. Longevity records of North American birds. Version 2015.2. Patuxent Wildlife Research Center, Bird Banding Laboratory 2015.
Partners in Flight. 2017. Avian Conservation Assessment Database. 2017.
Sibley, David Allen. 2014. The Sibley guide to birds, second edition. Alfred A Knopf, New York.