Limestone Leaf Warbler Phylloscopus calciatilis

Small, bright yellowish leaf warbler with a black-striped head. Entirely yellow underparts and tail distinguish this species from Yellow-vented Warbler and White-tailed Leaf Warbler. Sulphur-breasted Warbler is extremely similar, but Limestone averages incrementally longer-billed and paler yellow on the underparts. Specialist of lowland and mid-altitude karst hill forest. Like other leaf warblers, forages actively in foliage, often in flocks. Song is a subtly descending series of high tinkling notes; Sulphur-breasted’s song is snappier-sounding, with a distinctly ascending quality. Call is a two-note exclamation with a quiet first half: “bi-DEW!”