Snow Goose

The Snow Goose is one of the most numerous geese in North America, breeding in vast colonies across the Arctic tundra and migrating south each autumn in flocks that can number in the tens of thousands. It occurs in two color forms controlled by genetics: an all-white form and a gray-brown "blue goose" form, which regularly interbreed and are considered the same species.

White-morph body feathers are pure white with a strong, waxy sheen, contrasting sharply with jet-black primaries that give the classic "ink-dipped wingtip" look in flight and on shed feathers. Head feathers are frequently stained rusty-orange from iron-rich mud and plant matter while feeding, a useful clue even on a single feather. Blue-morph birds retain the white head but have gray-brown body and covert feathers with pale fringing. Feathers are broad-shafted and sturdy, typical of a grazing goose, and noticeably smaller than those of Snow Goose's close relative, the Ross's Goose, which has similar coloring but a shorter, more compact feather set.

Sexes are alike in both color morphs. Juveniles are dusky gray overall and lack the crisp white of adults, gradually whitening over their first year. The two color morphs are heritable and pair assortatively but freely interbreed, producing intermediate individuals. Adults undergo a flightless wing molt on the breeding grounds in summer.

Breeds colonially on open Arctic and subarctic tundra across northern Canada, Alaska, and Siberia. Winters in huge concentrations on coastal marshes, flooded agricultural fields, and refuges across the central and coastal United States and northern Mexico, often moving between roosting wetlands and feeding fields daily.

Feeds by grubbing roots, tubers, and shoots from marsh mud as well as grazing waste grain in farm fields, sometimes altering wetland vegetation where flocks are especially dense. Nests in open tundra colonies, timed to coincide with snowmelt. Extremely vocal and gregarious, giving loud, nasal honking calls almost continuously in large mixed flocks, and traveling in long skeins or dense clouds during migration.