Dusky Warbler

The dusky warbler is 14 centimetres long. The upperparts are uniformly dark grey-brown, and the bill is short, straight and tapering to a point. The best mark is the face pattern: a dark eye-stripe runs across the eye with a pale supercilium above it, plus a thin white eye-ring. The underparts are dirty white, the breast area sometimes slightly darker, and the flanks and undertail coverts cream. Unlike most leaf warblers the tail is slightly rounded. (German Wikipedia, general species account)

It breeds in East Asia and is a rare vagrant in Europe, though in recent times it has been recorded every year around the Baltic and North Seas. The Netherlands, for example, has 37 accepted records between 1978 and 2003, and birds were seen several times on Heligoland in 1996 and 1997. (German Wikipedia, general species account)