Behaviour This species is an intra-African migrant, making nomadic or partially migratory movements of several hundred kilometres to breed during the rains (Brown et al. 1982, del Hoyo et al. 1992). Populations north of the equator migrate northwards and those south of the equator migrate southwards (Brown et al. 1982, del Hoyo et al. 1992), both groups returning towards the equator at the end of the breeding season (Brown et al. 1982). Some populations (e.g. in southern Africa) may also be sedentary (Hockey et al. 2005). The species starts to breed during or shortly after the rains, although in flooded areas it also breeds during the dry season, usually nesting in large mixed-species colonies of 50-2,000 pairs (del Hoyo et al. 1992). It is a very gregarious species, often flying more than 30 km away from the colony to feed (Brown et al. 1982, Hockey et al. 2005). The species also roosts nightly in large numbers at breeding sites, on islets in rivers or flood-lands, on trees near dams, or in villages (Brown et al. 1982). Habitat The species mainly inhabits the margins of inland freshwater wetlands, sewage works (del Hoyo et al. 1992), saltpans (Martin and Randall 1987), farm dams (Hockey et al. 2005), rivers in open forest (Brown et al. 1982), grasslands, and cultivated fields, as well as coastal lagoons, intertidal areas, offshore islands (del Hoyo et al. 1992) and mangroves (Langrand 1990) (especially in the dry season) (Hancock et al. 1992). It may also occur in more human environments such as farmyards, abattoirs and refuse dumps on the outskirts of towns (del Hoyo et al. 1992). Diet Its diet consists largely of insects including grasshoppers, locusts, crickets, and aquatic beetles, although it will also take crustaceans, worms, molluscs, fish, frogs, lizards, small mammals, the eggs of Great White Pelican Pelecanus onocrotalus and crocodiles, nestling Cape Cormorants Phalacrocorax capensis, carrion, offal and seeds (Brown et al. 1982, del Hoyo et al. 1992, Hancock et al. 1992). Breeding site The nest is a large platform of sticks and branches built in trees or bushes, or placed on the ground on rocky islands (Brown et al. 1982, del Hoyo et al. 1992).