Gyrfalcon

The Gyrfalcon is the largest of all falcons, breeding across Arctic and subarctic tundra and coastal cliffs of North America, Greenland, Scandinavia, and Russia. It is well known for its striking plumage variation, ranging from almost pure white to nearly uniform dark gray-brown, all adapted to the harsh, open landscapes of the far north.

Feathers are notably larger and the wing base broader than those of Peregrine Falcon, reflecting the Gyrfalcon's greater bulk and power. The white morph shows mostly white feathers with variable, sparse dark spotting, the gray morph is barred gray-brown throughout, and the dark morph is nearly uniform sooty brown. The facial malar stripe, when present, is fainter and less bold than on Peregrine Falcon, another useful distinguishing feature.

White morph birds are mostly white with variable dark spotting concentrated on the back and wings, gray morph birds are barred gray-brown overall, and dark morph birds are nearly uniform sooty brown, with intermediates also occurring. Juveniles of all morphs tend to be more heavily marked and streaked than adults, becoming cleaner with successive molts. Geographic populations vary in the relative frequency of each morph, with white birds more common in the highest Arctic.

Gyrfalcons breed on Arctic and subarctic tundra and coastal cliffs across northern North America, Greenland, Scandinavia, and Russia. Most populations are resident or make only short-distance movements, though some individuals wander farther south during winter, particularly in years of prey scarcity.

It hunts ptarmigan and other birds using powerful, direct flight rather than the extreme high-altitude stoop typical of Peregrine Falcon. Nests are built on cliff ledges, often reusing sites used by other raptors in previous years, and the species gives deep, raucous calls near the nest site during the breeding season.