Schrenck's Bittern

Schrenck's Bittern (Ixobrychus eurhythmus) is a small chestnut-brown bittern; males show a dark back and cap, while females are more heavily spotted and streaked. 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 in reedbeds and wooded wetlands across eastern Asia, including Japan, migrates south for winter and takes fish, frogs and insects from dense waterside cover. 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).