Gyrfalcon
Gyrfalcon
Falco rusticolus
At a Glance
This formidable predator, the largest falcon in the world, reigns over barren tundra and desolate coasts in the high Arctic. There it preys mostly on large birds such as ptarmigan and waterfowl, overtaking them in powerful flight. Most Gyrfalcons remain in the far north all year; only a few come as far south as the Canadian border in winter, providing thrills for birders. Variable in color, Gyrs may be blackish, gray, or stunningly white.
All bird guide text and rangemaps adapted from by Kenn Kaufman漏 1996, used by permission of Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Category
Falcons, Hawk-like Birds
IUCN Status
Least Concern
Habitat
Coasts and Shorelines, Fields, Meadows, and Grasslands, Tundra and Boreal Habitats
Region
Alaska and The North, Eastern Canada, Great Lakes, Mid Atlantic, New England, Northwest, Plains, Rocky Mountains, Western Canada
Behavior
Direct Flight, Flap/Glide, Soaring
Population
83.000
Range & Identification
Migration & Range Maps
Many adults are permanent residents in far north, even above Arctic Circle, but many immatures move southward for winter. Northernmost adult breeders may also migrate.
Description
22" (56 cm). W. 4' (1.2 m). Most in North America are gray, but dark and white morphs also occur. Very large and broad-winged, but can be confused with the other two large falcons. All but the darkest Gyrs lack hooded effect of Peregrine; all lack the black wingpits of Prairie Falcon. Compare also to Goshawk.
Size
About the size of a Mallard or Herring Gull
Color
Black, Brown, Gray, White, Yellow
Wing Shape
Broad, Rounded
Tail Shape
Long, Rounded, Square-tipped
Songs and Calls
A chattering scream, kak-kak-kak-kak.
Call Pattern
Flat, Rising, Simple
Call Type
Chatter, Raucous, Scream
Habitat
Arctic barrens, seacoasts, open mountains. Breeds in Arctic regions having open tundra for hunting and cliffs for nesting sites. Often occurs along coasts and rivers, where prey may be more abundant. Mostly in treeless country, but occurs along the edges of northern forest in some places. Wintering birds south of Arctic tend to be either along coast or in very open country inland.
Sign up for 爆料公社's newsletter to learn more about birds like the Gyrfalcon
Behavior
Eggs
Usually 3-4, sometimes 2-5. White or creamy white, spotted with reddish-brown. Incubation is by both parents, but female does more.
Young
For first 1-3 weeks, young are brooded most of time, mostly by female; male does all or most of hunting during this time, bringing food which female feeds to the nestlings. After 2-3 weeks, female hunts also. Age of young at first flight about 45-50 days.
Feeding Behavior
Hunts by scanning its surroundings from a perch on a high rock, or while flying. Prey may be taken by surprise, the falcon approaching very low over the ground, or may be pursued relentlessly in flight over long distances.
Diet
Mainly birds, some mammals. Feeds mostly on medium-sized to large birds. Ptarmigan are mainstays of diet on Arctic tundra, while coastal Gyrs may take more gulls, ducks, and geese, but numerous other species eaten on occasion. Also some mammals, including lemmings, ground squirrels, hares. Wintering birds in west have been seen taking birds as large as Sage Grouse.
Nesting
Pairs may occupy nest sites very early in season, even in late winter. Members of pair display at nest site with bowing and scraping motions; male brings food to female. Nest: Most nest sites are on cliffs, and most are on old nests built by other birds, such as ravens or Golden Eagles. Sometimes breeds on open ledges with no nest structure present, and sometimes uses old nests in trees, such as spruce or poplar (tree nesting is frequent in some areas). Does not add material to existing nests.
Climate Vulnerability
Conservation Status
Has declined in parts of arctic Europe, but North American populations are probably stable. Illegal taking of young for falconry could be a problem in some areas, but most nest sites are remote from human disturbance.
Climate Threats Facing the Gyrfalcon
Choose a temperature scenario below to see which threats will affect this species as warming increases. The same climate change-driven threats that put birds at risk will affect other wildlife and people, too.