One of North America's rarest geese, the Emperor goose is small and stocky, with dark bluish-gray feathers and black barring on its upper parts. Male and female are similar, the female being slightly smaller than the male. Juveniles have a slightly duller coloring than the adults, having brown barring on their upper parts, gray mottling on their head and foreneck, olive-brown legs, and a black bill.
Emperor geese have a range which centers on the North Pacific Ocean in the Bering Sea. They breed in sub-Arctic and Arctic Alaska and along Russia's north-eastern coast. Most of the population winters along the Aleutian Islands' coasts, but may also winter in the Alaskan Peninsula and Canada. They inhabit open sites in arctic tundra during the mating season, either near inland lakes, coastal lagoons, or freshwater pools. In winter, they are mainly found on ice-free coasts.
Emperor geese in their wintering or nesting areas are relatively sedentary. Particularly when nesting, the pairs have little to do with other birds, except for defensive behavior if some other goose comes too close. During the non-migration seasons, emperor geese swim or walk much more often than they fly. They are diurnal and usually feed in their family groups, but in winter they gather in big flocks for molting. The mating adults molt in areas relatively nearby their breeding grounds, while the non-mating birds gather in large flocks at several other sites. The typical threatening actions of the emperor goose include bowing, head-jerking, and wing-flapping. The female will defend only the nest site, doing so aggressively in the postures she adopts and uttering loud calls.
In the summer, the diet of Emperor geese consists of vegetation, such as shoots, roots, and berries, while in the winter they primarily eat bivalve mollusks, which they use their sense of touch to catch, and algae.
Emperor geese are monogamous and will form a new bond only if their previous mate dies. Late May to early June is the period of the breeding season. They breed in loose colonies. Females select their nest site amongst low vegetation to have better visibility, and they build the nest on the ground, which is a shallow depression. It is lined with grass, down, and feathers. Males do not participate in nesting duties but remain nearby to defend the nest and the family against intruders. 1-8, but more commonly 5 creamy-white eggs are laid. The female incubates on her own for 24-25 days. The chicks are precocial, usually leaving the nest on their first day of life. They can walk and swim within hours. Goslings fledge about 50-60 days after hatching and become mature at 2-3 years of age.
The Emperor goose is threatened by hunting in Russia and coastal oil pollution. Habitat loss in the tundra as a result of climate change may impact negatively on this species in the very nearest future.
According to the IUCN Red List, the total population size of Emperor geese is estimated to number 85,000 individuals, while the population in Russia has been estimated at 100-10,000 breeding pairs. This species' numbers are decreasing today and it is classified as near threatened (NT) on the IUCN Red List.
In their consumption of mollusks, Emperor geese impact those populations significantly. It is thought that by grazing they increase the growth of vegetation in their habitat, therefore probably benefiting many organisms in the area that use vegetation for cover or food.