Small, active warbler with greenish upperparts, white underparts, distinct pale yellowish eyebrow, and distinct pale wingbars (upper wingbar short and less distinct). Overlaps in range with many other warbler species; compare especially with Hume’s Warbler, Pallas’s Leaf Warbler, and Two-barred Warbler. Breeds in mid- to high-elevation forests and winters in a wide range of wooded and scrubby habitats, where usually rather active; sometimes hovers to pick bugs from leaf tips. Call a distinctive, 2-syllable, upslurred "tsu-weet." Song is a very high, thin series of alternating long and short notes: “tseee-ts’a’wi-tseeeee.”