Kamchatka Leaf Warbler

Kamchatka Leaf Warbler (Phylloscopus examinandus) is a greenish leaf warbler with pale underparts, a strong eyebrow and narrow wing bars, closely resembling the Arctic warbler. 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 Kamchatka, Sakhalin, Hokkaido and the Kuril Islands, feeds on insects among foliage and migrates to Indonesia and the Philippines, with calls essential for reliable field separation. 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).