The snow goose is a medium-sized, chunky goose with a thin neck and stout bill. It occurs in two forms; a white morph and a dark morph, the latter often referred to as the blue goose. It is native to North America but is a rare vagrant to the UK and a frequent escapee from waterfowl collections. Historically, it was thought that the white and dark morphs of snow geese were two separate species, but they can interbreed and the offspring may be of either morph. A single dominant gene is responsible for the dark morph.
Breeding birds: 60 – 100 pairs
Family: Ducks, geese & swans
The white morph snow goose has white plumage all over except for black flight feathers. The dark morph has a pale grey lower neck, breast, and belly, and blue-grey upperparts and flanks. The wings are grey with white primaries and the vent, rump, and tail coverts are white, as are the head and the neck. The head can sometimes be stained rust-coloured from minerals in the soil where they feed.
The bill on both morphs is pinky-brown, the eyes are dark brown, and the legs and feet are pink.
Juvenile white morphs have a brown back, brown secondaries, and grey mottling on the head and neck. The bill and legs are brown. Juvenile dark morphs are similar but have no white on the head.
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Snow geese start breeding in June and nest in colonies. They are monogamous and form pair bonds. They breed on tundra near the coast, by ponds, shallow lakes, salt marshes, and streams. The female selects the site and builds the nest, which is a shallow depression situated on the ground and lined with moss, grass, and down.
Snow geese lay 4-5 cream-coloured eggs which are incubated for 22-25 days by the female alone while the male stays nearby guarding the nest. Chicks are precocial and are covered in olive or grey down. They are fed by both parents and fledge at 45-49 days after hatching but remain in the family group until the following breeding season. They reach sexual maturity at two years but don’t breed until they are three or four.
Snow geese eat a varied diet of aquatic plants such as seeds, stems, leaves, grasses, sedges, rushes, and rhizomes. They will also take agricultural crops as well as berries, and wild grains. They feed in water-logged soil or shallow water.
Snow geese arrive in the UK in October and leave again in April. Look out for them among flocks of white-fronted geese in flooded fields, marshes, and pasture in Scotland and Ireland.
Snow geese eat so much that they defecate up to 15 times an hour. The rate is highest when they eat rhizomes which are full of fibre and usually covered in mud.
