Dusky Warbler

The dusky warbler is a leaf warbler that breeds in the east Palearctic and is strongly migratory, wintering in South Asia and South-east Asia. The adult has an unstreaked brown back and buff underparts, a prominent whitish supercilium and a fine pointed bill. The sexes are identical, but young birds are more olive-tinged above (Wikipedia, general species account).

The nest is built low in a bush, with five or six eggs. The song is a monotonous whistle and the call a harsh 'check', often the first clue that this typically skulking species is present away from the breeding grounds. It is prone to vagrancy as far as western Europe in October. The account opened does not name Bhutan.