They are small songbirds, at most long. In most subspecies, the underparts of both male and female are bright yellow, the backs are a dull brown colour. The forehead, throat and upper breast of the adult male is a dark, metallic blue-black. In the Philippines the males of some subspecies have an orange band on the chest, in Wallacea and northern New Guinea some subspecies have most of the underparts blackish, and in southern China and adjacent parts of Vietnam most of the underparts of the male are greyish-white.
