Behaviour This species is mainly sedentary, although the southern African population is more nomadic, undertaking considerable local movements (up to 50 km (Brown, et al. 1982)) with the availability of seasonal wetlands (Brown, et al. 1982, Scott and Rose 1996). It forms huge colonies in the non-breeding season, but disperses to breed at the onset of the rainy season (Brown, et al. 1982). Adults undergo a post-nuptial wing moult three or four months after the peak of the breeding season, rendering them flightless for a period of about four weeks (Johnsgard 1978, Kear 2005b). The species is mainly nocturnal: typically foraging at dusk and after dark whilst remaining sedentary throughout the day (Johnsgard 1978). Habitat This species frequents slow-flowing rivers with pools and adjacent flooded grasslands, permanent and seasonal lakes, streams, marshes, brackish coastal lagoons, artificial reservoirs associated with mining, dams, salt pans, sewage works and the open water of estuaries (del Hoyo, et al. 1992, Hockey, et al. 2005, Kear 2005b). It cannot tolerate highly acidic habitats or those where sodium chloride concentrations are very high, but can tolerate high concentrations of other salts around pH 10 or more (Brown, et al. 1982). It also avoids fast-flowing water (Hockey, et al. 2005). Diet It is omnivorous, with a diet consisting of the fruits, seeds, roots, leaves and stems of aquatic and terrestrial plants, aquatic insects and their larvae (including mayflies, water beetles and grasshoppers) (Hockey, et al. 2005), crustaceans, molluscs and agricultural grains such as maize and sunflower seeds (Brown, et al. 1982, del Hoyo, et al. 1992). Breeding site The nest of this species is situated on the ground and is made of grass, rushes and reed stems (Brown, et al. 1982, del Hoyo, et al. 1992). It is usually protected and screened from above by dense, overhanging vegetation (del Hoyo, et al. 1992) and some nests may have tunnel access through the surrounding grass (Brown, et al. 1982).