Siberian House Martin

Siberian House Martin (Delichon lagopodum) is a compact black-and-white martin with a bright white rump, white underparts and feathering extending onto its feet. 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 colonially on rocky cliffs and structures in north-eastern Asia, catches flying insects over open terrain and migrates to mainland Southeast Asia for the northern winter. 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).