This large brown bird has a dark brown mask around the eye, and a brown patch on the breast that is distinctive in flight. Compared with South African Shelduck it has a longer neck and legs, and a thin, dark line running through the white forewing is visible in flight.
Juvenile lacks the brown mask and breast patch, and the forewing is nog pure white.
Almost any freshwater habitat but frequently feeds in fields.
Male hisses, female utters a grunting honk; both give rapidly repeated honks at take-off.