Smeđoboka belooka Zosterops erythropleurus

The most migratory of the Asian white-eyes, this minute bird breeds in the boreal woodlands of far northeastern China and Russia and winters in southern China and northern Southeast Asia. Frequently migrates in immense flocks and can often be seen in gatherings of thousands on headlands and islands. Bright yellow-green upper body, white underparts, and striking white eye ring give this species the general white-eye look, but the broad brush-stroke of rufous on the flanks distinguishes it from similar species. Vocalizations consist largely of high, sweet, rising “sweee”s.