Red-footed Booby

Red-footed Booby (Sula sula) is the smallest booby, identified in every colour form by its bright red feet and slender bluish bill. 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 inhabits tropical seas, plunge-diving for fish and squid, and differs from most boobies by commonly placing its nest in trees or shrubs at island colonies. 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).