Eurasian Treecreeper

Eurasian Treecreeper (Certhia familiaris) is a tiny bark-coloured bird with mottled brown upperparts, white underparts, a curved bill and stiff pointed tail feathers. 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 spirals upward around trunks in northern Eurasian woodland, probing bark crevices for insects before flying to the base of another tree, and nests behind loose bark or in narrow cavities. 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).