Spur-winged Goose  (Plectropterus gambensis)

Regional Status

IUCN Data (Global)

IUCN 2024. IUCN Red List of Threatened Species. Version 2024-1 (www)

Assessment year: 2016

Assessment Citation

BirdLife International 2016. Plectropterus gambensis. The IUCN Red List of Threatened Species 2016: e.T22680057A92840685. https://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T22680057A92840685.en. Accessed on 22 December 2024.

Habitats:

Behaviour This species is partially migratory, making seasonal movements (del Hoyo et al. 1992) of several hundred kilometres (Brown et al. 1982) related to the availability of water (del Hoyo et al. 1992). It breeds during or near the end of the wet season in solitary pairs (del Hoyo et al. 1992) although it may also feed in small groups during this period (Kear 2005a). The species congregates after breeding (at the beginning of the dry season) (del Hoyo et al. 1992) to undergo a flightless moulting period lasting for c.50 days (Kear 2005a) (6-7 weeks) (Johnsgard 1978), the males moulting before the females (Kear 2005a). It is commonly found in small groups of up to 50 individuals (Madge and Burn 1988) and occasionally aggregates into larger flocks (e.g. when moulting) (Kear 2005a). In the winter it rests by day and feeds in the early morning, evening or at night (Kear 2005a), sometimes perching in trees to roost (Brown et al. 1982). Habitat The species inhabits seasonal and permanent wetlands (Kear 2005a) near grasslands or arable land (del Hoyo et al. 1992), including lakes, rivers (del Hoyo et al. 1992), inland river deltas (Madge and Burn 1988), marshes (del Hoyo et al. 1992), swamps, flooded grasslands, pastures (Kear 2005a), reservoirs (del Hoyo et al. 1992), farm impoundments (Hockey et al. 2005) and sewage works (Johnsgard 1978), particularly those with emergent and fringing vegetation (Kear 2005a) and surrounded by scattered trees (del Hoyo et al. 1992). When moulting it frequents areas with open shorelines, islands and sandbars (Kear 2005a), generally avoiding saline lakes and upland areas (Madge and Burn 1988). Diet Its diet consist predominantly of plant matter such as the vegetative parts and seeds of grasses, sedges and aquatic plants (del Hoyo et al. 1992), agricultural grain (del Hoyo et al. 1992), fruit (e.g. figs) (Kear 2005a) and tuberous crops (Johnsgard 1978) (e.g. sweet potatoes) (Kear 2005a), although it may occasionally take small fish (del Hoyo et al. 1992) or insects (Kear 2005a). Breeding site The species shows a preference for nesting in hollow trees, tree-cavities or in the abandoned nests of other tree-nesting bird species (del Hoyo et al. 1992) (e.g. Hamerkop Scopus umbretta (Madge and Burn 1988), African Fish-eagle Haliaeetus vocifer or Social Weaver Philetairus scoius (Brown et al. 1982)), often between 20 and 100 cm high in trees 3-4 m tall (Hockey et al. 2005). Where tree-nesting sites are unavailable (Brown et al. 1982), it will also nest on the ground (del Hoyo et al. 1992) in long grass or reeds near water (Brown et al. 1982), in rock cavities, holes in termite mounds (Madge and Burn 1988), or even in aardvark Orycteropus afer burrows (Brown et al. 1982).

Threats:

The species is threatened by uncontrolled hunting (declines in Botswana have been attributed to hunting outside of protected areas) (Hockey et al. 2005). Utilisation The species is hunted and traded at traditional medicine markets in Nigeria (Nikolaus 2001).

Rationale:

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 increasing, 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.

Trend justification:

The overall trend is increasing, although some populations may be stable (Wetlands International 2006).