Behaviour This species is mainly sedentary (del Hoyo et al. 1992, Hockey et al. 2005) but is subject to little known opportunistic local movements related to drought and wetland conditions (Brown et al. 1982, del Hoyo et al. 1992, Hockey et al. 2005). The timing of breeding is seasonal in some areas, but can be at any time of the year (del Hoyo et al. 1992). The species usually breeds in mixed-species colonies (Brown et al. 1982, del Hoyo et al. 1992, Hockey et al. 2005), and roosts nightly in groups of 10 to 50 (Hockey et al. 2005) (sometimes up to 100) in trees, bushes or reedbeds often in mixed-species groups (Brown et al. 1982), although it is generally a solitary feeder (Brown et al. 1982, Johnsgard 1993). Its moulting habits are little known, but some adults may go through a flightless moult period after breeding (Hockey et al. 2005). Habitat The species shows a preference for still, shallow, inland freshwater and alkaline lakes and slow-flowing rivers fringed with reeds and trees (Brown et al. 1982, del Hoyo et al. 1992, Johnsgard 1993). It may also occur in swamps (del Hoyo et al. 1992, Johnsgard 1993), reservoirs (del Hoyo et al. 1992, Johnsgard 1993, Hockey et al. 2005), river oxbows (Johnsgard 1993) and forested streams (Brown et al. 1982), typically avoiding marine habitats (Hockey et al. 2005) but occasionally foraging inmangrove swamps (del Hoyo et al. 1992), estuaries (Brown et al. 1982, del Hoyo et al. 1992, Johnsgard 1993, Hockey et al. 2005), shallow tidal inlets (Brown et al. 1982, del Hoyo et al. 1992) and coastal lagoons (Brown et al. 1982, del Hoyo et al. 1992, Hockey et al. 2005). It generally avoids fast-flowing rivers, areas with dense floating vegetation (Hockey et al. 2005), and narrow, steep-banked or seasonally drained habitats (Johnsgard 1993), preferring to feed in water 1-3 m deep (up to 6 m [Hockey et al. 2005]) with forested margins or scattered emergent trees and islets with dense vegetation (del Hoyo et al. 1992). The species requires trees, bushes or reedbeds for roosting (Brown et al. 1982), and prefers dead trees, rocks or banks to rest on after feeding (Hockey et al. 2005). Diet Its diet consists mainly of fish such as Cichlidae and Cyprinidae (del Hoyo et al. 1992), although it will also take amphibians, water snakes, terrapins, aquatic insects, crustaceans and molluscs (del Hoyo et al. 1992). Breeding site The species nests in mixed-species colonies (Brown et al. 1982, del Hoyo et al. 1992), each pair building a nest platform of sticks and other vegetation (del Hoyo et al. 1992) in forks of trees or in reedbeds 1-6 m high (Brown et al. 1982) (often c.2 m [del Hoyo et al. 1992]) over water or on islands (Hockey et al. 2005).