Bird of the Month: Gyrfalcon

By Hugh Jennings

PC: Mick Thompson (Gyrfalcons)

PC: Mick Thompson (Gyrfalcons)

Scientific Name: Falco rusticolus

Length 22" long

Wingspan 47"

Weight 3.1 lb. (1400 g)

AOU Band code GYRF

The Gyrfalcon (GYRF) is about 22” long with a wingspan of 47” and weight of 3.1 lb. (1400 g).  It is the largest falcon in the world.

The genus name Falco (FAL-koh) is Latin for hawk, referring to the hooked (falcate) shape of the claws. The species name rusticolis (russ-TICK-oh-lus) is from the Latin rusticola, living in the country. The common name (JER-fall-kon) is from Latin gyrfalcon, or girofalco, said to be a Low Latin corruption of hierofalco, or “sacred falcon” for a bird so highly revered by falconers. This swift, powerful species is mostly found on the Arctic tundra. Most of the Gyrfalcons are an overall gray, but there white and dark morphs. The white morph nests primarily in northern Greenland, while the dark morph nests in Labrador. The gray morph is widespread and is the one that occurs in the Pacific NW. It is a heavy-bodied falcon with long, broad wings with pointed tips and a relatively long tail. The gray morph has gray upperparts, a whitish body with gray spotting or streaking on the breast and belly. Sometimes a weak, or thin, mustache is visible. It is usually found in open and semi-open areas, such as marshes, fields and wetlands where prey is abundant. Most of the Gyrfalcons remain in the far north all year. Only a few come as far south as the Canadian border in winter. West of the Cascades the GYRF is a rare winter resident on the Samish and Skagit Flats, Dungeness Spit and Ocean Shores. In Eastern Washington they are most likely seen on the Waterville Plateau, Davenport-Reardan area and north of Moses Lake. They do not nest in Washington. Most of the Gyrfalcons seen in Washington are immatures which are more  brown overall instead of gray. There is a lot of pressure worldwide on Gyrfalcons as they are collected from the wild and sold to falconers in other countries for large sums of money.

In Alaska, the GYRF feeds mostly on birds, mainly on ptarmigans and grouse. Some of the mammals used for food are lemmings, squirrels and hares. In Washington they feed mainly on waterfowl, upland game birds such as Ring-necked Pheasant and Gray Partridge, shorebirds and Rock Pigeon. They hunt by scanning the area from a perch on a high rock or while flying. It most often attacks in a level chase low over the ground and simply outflies its prey, often attacking from below. It strikes in mid-air and then carries the prey or follows it to the ground. Their alarm call is a loud kak-kak-kak or harsh kikikikiki. Gyrfalcons nest in the Arctic tundra and and use cliff sites or old nests built by other birds in spruce or poplar trees, such as ravens or Golden Eagles. They do not add material to existing nests. Three to four white or creamy white eggs  spotted with reddish brown are usually laid. Incubation is by both parents, but mainly by the female, and lasts about 35 days. For the first 1-3 weeks the young are brooded mostly by the female. The male does most of the hunting and brings food to the female which she feeds to the nestlings. The female begins hunting after about 2-3 weeks. The young make their first flight after about 45-50 days.