Comb ducks are usually found in single pairs or, particularly in parts of Africa, small groups (harems) during the breeding season, and in groups of up to 30 to 40 birds at other times, when they may join flocks of other wildfowl. Harems are not known in Asia (3), and the species’ social structure is poorly known in South America (2). The diet consists mainly of vegetable matter, such as aquatic vegetation, seeds of grasses and sedges, grain (including crops such as rice and corn), as well as various invertebrates, such as aquatic insect larvae and locusts (4) (10).
Comb ducks usually nest close to water, in large tree cavities, holes in the walls of isolated buildings, abandoned nests of other birds, including that of the hamerkop (Scopus umbretta), or sometimes on the ground. The nest is a rough structure built from twigs and course grass, and is lined with grass, leaves and feathers (4) (10). The breeding season is variable, but usually coincides with the rainy season (4). In some areas comb ducks are monogamous, while in others males may hold small harems of two to four females, which they defend against other males (7) (12). Between 6 and 20 eggs may be laid (4), though nests sometimes contain the eggs of more than one female (7). Incubation lasts 28 to 30 days, and is performed exclusively by the female (4) (12). Within just a day or two of hatching, the ducklings leap from the nest, which may be up to 12 metres above the ground (10), when summoned by the female (7). Fledging occurs at about ten weeks (4) (7).