Justification of Red List Category
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be stable, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
The overall population trend is stable or increasing, but some populations have unknown trends (Wetlands International 2006).
Behaviour This species is sedentary (del Hoyo et al. 1992) but often makes local movements in semi-arid areas (Brown et al. 1982) and disperses during the rains (del Hoyo et al. 1992). It breeds all year round in East Africa, but elsewhere breeding peaks mostly late in the rains or in the dry season (del Hoyo et al. 1992). The species nests solitarily (del Hoyo et al. 1992) and usually occurs in pairs or in small groups of 8-10 individuals outside of the breeding season, sometimes also occurring in social groups of more than 50 (Brown et al. 1982). Habitat The species occupies a wide variety of habitats (del Hoyo et al. 1992) from forest to semi-desert, wherever water is available (Brown et al. 1982). It is commonest in well-watered savanna or woodland and less common in forest, showing a general preference for permanent waters although it will also use temporary wetlands in arid areas (Brown et al. 1982). The species forages in shallow water along sandbanks, in reedbeds or in floating vegetation (Brown et al. 1982) and requires trees (e.g. Khaya senegalensis) to nest and roost in (Brown et al. 1982, del Hoyo et al. 1992). Suitable habitats include the banks of large rivers and lakes (Brown et al. 1982, del Hoyo et al. 1992), marshes, dams, temporary seasonal ponds (Brown et al. 1982), aquaculture ponds, irrigation schemes and estuaries as well as rocky coasts in Tanzania (del Hoyo et al. 1992). Diet Its diet consists predominantly of amphibians (especially Xenopus spp. adults and tadpoles) and small fish as well as crustaceans, worms and insects (del Hoyo et al. 1992). Breeding site The nest is an elaborate hollow structure of sticks usually built in a fork of a tree (del Hoyo et al. 1992) overhanging water, but alternatively built on cliff ledges, rock columns, on the ground or on sandbanks (Brown et al. 1982). The species shows a preference for nesting in dead trees standing in water and usually roosts in or near its nest (Brown et al. 1982).
The species is potentially threatened by a deterioration in wetland water quality caused by the excessive use of pesticides (del Hoyo et al. 1992). Utilisation The species is hunted and traded at traditional medicine markets in Nigeria (Nikolaus 2001).
Text account compilers
Butchart, S., Malpas, L., Ekstrom, J.
BirdLife International (2017) Species factsheet: Scopus umbretta. Downloaded from http://www.birdlife.org on 11/12/2017. Recommended citation for factsheets for more than one species: BirdLife International (2017) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 11/12/2017.