Length 55-65 cm, wingspan 88-105 cm, mass 530-768 g
Males larger than females
Bill brownish, long, thin, and evenly decurved; legs reddish-brown to olive-grey.
Breeding adult: Body reddish-brown and wings glossy bottle-green. There is a norrow white to cobalt blue line around the base of the bill.
Non-breeding adult and juvenile: Body duller.
Inhabit permanent wetlands including coastal lagoons and marshy lakeshores.
These birds are gregarious and may occur in large flocks containing hundreds of birds.
Food includes invertebrates, fish, frogs and small reptiles.
The nest is a compact platform of twigs or reeds, about 30 cm diameter, usually in a tree which overhangs water. Nesting is colonial and often in mixed heronries. Two to four eggs are laid August to March (in southern Africa). Incubation is by both sexes and takes 20-23 days.