Glaucous Gull

Glaucous Gull (Larus hyperboreus) is a huge, very pale gull with no black in the wingtips, a heavy bill and pink legs. Body shape, bill structure, plumage pattern and voice provide the strongest field characters. Age, sex and season may alter its appearance, so identification should combine several features and careful direct field comparisons with similar species in the same habitat (Wikipedia, general species account).

It breeds around Arctic coasts and scavenges fish, eggs, carrion and refuse, moving south to ice-free shores in winter. Its movements and social behaviour vary through the year, with breeding birds generally more dispersed and non-breeding birds gathering where food is concentrated. Japanese records place it within the country's documented avifauna as a resident, migrant or visitor (Wikipedia, general species account; Wildlife of Japan occurrence records).