[order] ANSERIFORMES | [family] Anatidae | [latin] Plectropterus gambensis | [authority] Linnaeus, 1766 | [UK] Spur-winged Goose | [FR] Oie-armee de Gambie | [DE] Sporngans | [ES] Ganso Espolonado | [NL] Spoorwiekgans | [copyright picture] Jan Dolphijn
The Spur-winged Goose, (Plectropterus gambensis), is a large bird in the family Anatidae, related to the geese and the shelducks, but distinct from both of these in a number of anatomical features, and therefore treated in its own subfamily, the Plectropterinae. It occurs in wetlands throughout sub-Saharan Africa.
They are the largest African waterfowl and are, on average, the world’s largest “goose”. They are mainly black, with a white face and large white wing patches. The long legs are flesh-coloured. The nominate race P. g. gambensis has extensive white on the belly and flanks, but the smaller-bodied subspecies P. g. niger, which occurs south of the Zambezi River, has only a small white belly patch. The male differs from the female, not only in size, but also in having a larger red facial patch extending back from the red bill, and a knob at the base of the upper mandible. This is a quiet species, but may give a thin whistle in flight.
Listen to the sound of Spur-winged Goose
Copyright remark: Most sounds derived from xeno-canto
Africa : widespread
The species inhabits seasonal and permanent wetlands near grasslands or arable land, including lakes, rivers, inland river deltas, marshes, swamps, flooded grasslands, pastures, reservoirs, farm impoundments and sewage works, particularly those with emergent and fringing vegetation and surrounded by scattered trees. When moulting it frequents areas with open shorelines, islands and sandbars, generally avoiding saline lakes and upland areas.
The species shows a preference for nesting in hollow trees, tree-cavities or in the abandoned nests of other tree-nesting bird species (e.g. Hamerkop Scopus umbretta, African Fish-eagle Haliaeetus vocifer or Social Weaver Philetairus scoius), often between 20 and 100 cm high in trees 3-4 m tall. Where tree-nesting sites are unavailable, it will also nest on the ground in long grass or reeds near water, in rock cavities, holes in termite mounds, or even in aardvark Orycteropus afer burrows.
Breeding starts near end of rainy season. Mainly September to January in South Africa, mostly January to March in Zambia. Clutch size is 6-14 eggs which are incubated by the female for about 30-33 days. The young fledge after 10 weeks and are usually tended by female only, male may sometimes remain with brood in East Africa. This species may engage in nest-dumping.
Its diet consist predominantly of plant matter such as the vegetative parts and seeds of grasses, sedges and aquatic plants, agricultural grain, fruit (e.g. figs) and tuberous crops (e.g. sweet potatoes), although it may occasionally take small fish or insects.
copyright: Peter van Dam
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.
The species is threatened by uncontrolled hunting (declines in Botswana have been attributed to hunting outside of protected areas). The species is hunted and traded at traditional medicine markets in Nigeria.
This species is partially migratory, making seasonal movements of several hundred kilometers related to the availability of water. It breeds during or near the end of the wet season in solitary pairs although it may also feed in small groups during this period. The species congregates after breeding (at the beginning of the dry season) to undergo a flightless moulting period lasting for c.50 days (6-7 weeks), the males moulting before the females. It is commonly found in small groups of up to 50 individuals and occasionally aggregates into larger flocks (e.g. when moulting). In the winter it rests by day and feeds in the early morning, evening or at night, sometimes perching in trees to roost.