Behaviour This species makes little known⁷ dispersive movements^{1, 3} related to water conditions^{1, 2}. It is locally nomadic in southern Africa in response to changing wetland conditions⁶, and western African populations make northward movements into sub-Saharan steppe during the wet season, returning southwards in the dry season^{1, 2, 4}. The species breeds all year round, although most start late in the wet season^{1, 3, 4}. It is gregarious both during breeding and non-breeding⁵, nesting in small groups or larger loose colonies of between 20 and 500 pairs^{1, 2, 7} (often alongside other species^{3, 5}). It roosts nocturnally in groups⁴, but is more of a solitary feeder, preferring to fish singly or in small loose groups of less than 30 individuals^{3, 4, 5}. It is chiefly diurnally active, especially during the morning and evening, although it may also fish on moonlit nights^{2, 5}. Habitat The species inhabits a wide range of aquatic habitats, but prefers to feed in quiet backwaters and weed-grown lagoons¹ where there is shallow water and emergent vegetation⁵, generally avoiding steep, vegetated lake margins³. It shows a preference for freshwater lakes, swamps, large slow-flowing rivers, and seasonal pools^{1, 2, 3, 4, 5}, but also frequents reservoirs^{2, 4}, seasonally flooded land³ and flood-plains near river mouths⁷. It may occur on alkaline and saline lakes and lagoons^{2, 3, 4, 5}, and can sometimes be found along the coast in bays¹ and estuaries^{2, 3, 5} (although seldom on open seashore)^{2, 3}. The species tends to roost and breed in trees (e.g. mangroves), but will also roost on sandy islands, cliffs, coral reefs and sand-dunes¹. Nesting trees are often killed by repeated nesting, which forces breeding colonies to move (although birds will usually not move far)^{1, 2}. Diet The diet of this species consists entirely of fish (of any size up to 450 g, although usually in the range of 80-290 g)³, with cichlids (especially Haplochromis and Tilapia) being preferred^{1, 2, 3, 4}. Breeding site The species nests colonially in trees, reeds or low bushes along waterfronts^{1, 2, 3} as well as (less often) on the ground on sandy islands and in mangroves^{1, 3}. The nest is small and constructed of sticks¹, and may be situated at elevations of 10-50 m above the ground⁴. A single tree may contain many nests³ that can be very close together (often touching)⁷, and a single pair will refurbish and re-use the same nest from year to year if it has not collapsed³.