Snow Goose

Snow Goose (Anser caerulescens) is a medium goose occurring in white and dark blue morphs, both with pink bills and black wingtips. The combination of body shape, bill structure, plumage pattern and voice provides the most useful field characters. Age, sex and season can alter its appearance, so identification should use several features rather than colour alone. This supports comparison with similar species in the field (Wikipedia, general species account).

It nests colonially on Arctic tundra and migrates in large flocks to marshes, fields and shallow wetlands. Its movements and social behaviour vary through the year, with breeding birds generally more dispersed and non-breeding birds more likely to gather where food is concentrated. Japanese records place it within the country's documented avifauna as a resident, migrant, visitor or introduced bird (Wikipedia, general species account; Wildlife of Japan occurrence records).