The Arctic Warbler is a relatively unmarked olive-brown warbler with a prominent yellowish-white eyestripe, faint wingbars and pale whitish underparts.
They breed in the very northern parts of the world (hence the name Arctic Warbler) like Eurasia, Siberia, northeast China, Japan to Alaska but they all winter in southeast Asia.

Sungei Buloh Wetland Reserve, Singapore, 8 November 2022