Tiny, chunky, sprightly warbler with a short tail and a big head. Strong head pattern: three bright yellow stripes on an olive green head. Overlaps considerably with other similar leaf warblers throughout non-breeding range, so identification warrants caution; always note strong head pattern, bright yellow rump, and overall bright coloration. Very active while feeding, often hovering to pick insects from leaves. Joins mixed-species flocks. Breeds in coniferous and mixed forest in the Siberian taiga, and winters in a wide range of forested and semi-wooded habitats. Song complex and prolonged, a beautiful rambling series of clinking, chirping, trilling, and warbling with many repeated phrases. Call is a twangy “jwee.” Vagrants often turn up in trees on coastal headlands.