Lesser Black-backed Gull

Lesser Black-backed Gull (Larus fuscus) is a large gull with dark slate upperparts, yellow legs and a yellow bill bearing a red spot. 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 northern coasts, migrates widely and feeds opportunistically on fish, invertebrates, carrion and refuse. 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).