Red-legged Kittiwake

Red-legged Kittiwake (Rissa brevirostris) is a compact North Pacific gull with red legs, short yellow bill, dark grey wings and large dark eyes. 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 comparisons with similar species in the same habitat (Wikipedia, general species account).

It nests on steep Bering Sea cliffs and feeds offshore on fish and marine invertebrates, often in productive upwelling zones. 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).