Gull-billed Tern

Gull-billed Tern (Gelochelidon nilotica) is a sturdy pale tern with a thick black bill, black breeding cap, long legs and shallowly forked tail. 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 hunts insects and small vertebrates over marshes and fields more often than plunge-diving, and nests colonially on bare ground. 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).