Small songbird, dull brownish-olive above, pale below, with prominent white supercilium, black eyeline, and faint, narrow wingbars. Vertical tail pumping distinguishes this species from most others in its range except Sakhalin Leaf Warbler. Favors the lower stories of vegetation more than most other leaf warblers, often descending down to the ground while foraging. A high-pitched cricket-like trill of a song distinguishes this species from the nearly identical Sakhalin on migration (no overlap in breeding range). Calls of the two species are similar, and can only be differentiated reliably using a spectrogram; Pale-legged’s call is marginally higher in frequency. Breeds in sparsely wooded areas, particularly in valleys and hills; can be seen in a wide range of wooded habitats outside of breeding period.