Gyrfalcon

Falco rusticolus

Order FALCONIFORMES - Family FALCONIDAE - Subfamily Falconinae

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1. Cool Facts
2. Description
3. Similar Species
4. Sound
5. Range
6. Habitat
7. Food
8. Behavior
9. Reproduction
10. Conservation Status
11. Other Names

The largest falcon in the world, the Gyrfalcon breeds in arctic and subarctic regions of the northern hemisphere. It preys mostly on large birds, pursuing them in breathtakingly fast and powerful flight.

Cool Facts

• The Gyrfalcon eats mostly ptarmigan, but many other prey species have been recorded, including fulmars, gulls, jaegers, ducks, geese, Rough-legged Hawk, Short-eared Owl, sparrows, buntings, and redpolls.

• The female Gyrfalcon regularly stores prey during the breeding season, generally within 100 meters (328 feet) of the nest. Little is known of food-caching outside the breeding season; in one case, a Gyrfalcon was seen retrieving a frozen ptarmigan and chipping off pieces of meat to eat, in mid-winter in the Aleutian Islands.

• Gyrfalcon is pronounced as "JER-falcon." The name probably evolved from Old Norse, but linguists do not completely agree on the specific origin of the word.

• The Gyrfalcon sometimes bathes in runoff water of still-frozen rivers.

Description

• Size: 48-64 cm (19-25 in)
• Wingspan: 123 cm (48 in)
• Weight: 800-2100 g (28.24-74.13 ounces)

• Large falcon.
• Broad-chested appearance.
• May range from nearly pure white to dark gray to black, with variable barring and streaking; most are gray.
• Faint mustache mark on face.
• Long, broad, pointed wings.
• Long, barred tail.

• Dark form has pale flight feathers contrasting with darker wing linings.
• Large dark eyes.
• Tips of folded wings do not extend past tail tip.
• Bill yellow with dark tip.
• Cere and feet yellow.

Sex Differences

Sexes similar; female larger.

Immature

Similar to adult, but more heavily marked on breast and belly; streaked instead of barred or spotted like adult. Cere and feet blue-gray.

Similar Species

• Peregrine Falcon can be very similar, but is smaller, with more distinct white-and-dark facial pattern, distinct mustache stripe, proportionally slimmer wings, and longer tail.
• Prairie Falcon is smaller, slimmer, browner, and has dark wingpits.

Sound

Alarm call is a guttural "kak, kak, kak." Contact call, given during foraging and food transfer, is a sharp "chup..chup?chup."

»listen to songs of this species

Range

Summer Range

Breeds at high northern latitudes, from approximately 60° to 79° N. Breeding range includes parts of Alaska, Canada, Greenland, Scandinavia, and Siberia.

Winter Range

Winter movements are not completely understood. Most birds resident year-round in their breeding range. Some regularly winter as far southward as southern Canada. Occurs rarely in winter in the northern United States. Old World populations winter as far southward as central Asia.

Habitat

Breeds in tundra, often near rivers or coasts. Winter habitat similar; at lower latitudes, open country, especially near water.

Food

Mostly birds, especially ptarmigan. Also consumes mammals, ranging in size from voles to hares.

Behavior

Foraging

Uses four methods to pursue prey: 1) flying low and surprising prey on ground; 2) pursuing prey over long distances, forcing it low or high and exhausting it; 3) hovering and making short stoops to force prey out of cover; 4) flying straight up to strike at birds overhead. Strikes prey or drives it to the ground, rather than grasping it in the air; dead prey typically have broken breast bone.

Displays

Male performs spectacular aerial displays with dives and 180° rolls.

Reproduction

Nest Type

Does not build nest; usually uses nests built by other species, including Common Raven and Golden Eagle, usually on cliff ledge.

Egg Description

White with variable cinnamon spots; may be mostly brown.

Clutch Size

Usually 3-5 eggs. Range: 1-5.

Condition at Hatching

Covered with thick down; capable of sitting up and begging shortly after hatching.

Conservation Status

No evidence of long-term population changes in North America. Commercial markets in falconry may pose a threat in Scandinavia and Russia.

Other Names

Faucon gerfaut (French)
Halcón gerifalte (Spanish)

Sources used to construct this page:

Clum, N. J., and T. J. Cade. 1994. Gyrfalcon (Falco rusticolus). In The Birds of North America, No. 114 (A. Poole and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington, D.C.: The American Ornithologists' Union.