Sexes dissimilar ; the adult male being black, the adult female spotted or barred. The changes in the young are peculiar, the nestling, in the only species in which the various phases have been studied, having the Coloration of the adult male, then changing into a garb resembling that of the female.
The bill is stout, the culmen rounded and much curved; the wing and tail subequal in length, the latter moderately graduated, the rectrices broad. No crest. Legs stout; tarsus strongly scutellate in front, only plumed at the extreme base.
The genus ranges throughout the Oriental region to New Guinea and Australia. About six species are known, only one of •which inhabits India.