The spur-winged goose is a relatively large bird, and it is a member of the family Anatidae.
The bird is closely related to the geese and the shelducks, but it differs from these birds’ anatomy. For this reason, it is given its subfamily, the Plectroperinae.
The birds can be found across sub-Saharan Africa in wetlands.
|Scientific name||Plectropterus Gambensis|
The adult birds usually have a body length between 30 to 45 inches, and their weight can be between 4 to 7 kilograms. The males are generally on the high side of the weight statistics while the females are on the low side.
The sexual dimorphy is prominent as the males are considerably larger than the females. Their wingspan averages between 59 to 79 inches in length.
The wing chord measures between 17 to 18 inches, the bill measures between 2.2 to 2.5 inches, and the tarsus measures between 2.2 to 4.7 inches.
The spur-winged goose is the biggest waterfowl in Africa, and it is also regarded as the world’s largest wild “goose”. Although, a certain goose species, the Cape Barren goose rivals them in weight.
The spur-winged geese seem to be more closely affiliated to the shelducks than “true geese” such as birds from the Anser and Brants genera.
The birds are primarily black with big, white wing patches and a white face. The birds have pinkish-red, lengthy legs. The stomach area and the sides are extensively white.
Apart from differences in size and weight, the male can also be distinguished from the female based on having a more prominent, red patch on the face. It stretches from the red bull and a knob at the bottom of the upper mandible.
The spur-winged geese are usually a quiet species. The bird often contains poison because it consumes blister beetles. The poison is called cantharidin, and it is contained in the tissue of the fowl.
This makes the flesh of the spur-winged geese inedible as eating it will result in food poisoning. Studies have claimed that about 10 milligrams of cantharidin can lead to the death of a human.
Usually, only the male goose utters a call, which comprises a soft gurgling chew when it is alarmed or displaying its wing.
During mating displays or in events of alarm, both genders tend to make other inconspicuous calls. The spur-winged goose is a social bird, and it usually mingles in small flocks that may have birds numbering up to 50.
The spur-winged goose is very aggressive to other waterfowls (not excluding conspecifics) during the mating season.
The goose tends to violently place the spur on its wings’ curve to clash with other birds. The adult males are very likely to attack fellow males during the mating season.
Multiple sites may be used for shedding their feathers after mating, in which case, huge numbers of the geese may assemble. The dispersion may happen to pursue feeding opportunities outside of the mating season.
This spur-winged goose feeds by grazing on vegetation but spends the afternoon resting by a body of water. The goose’s diet comprises primarily of plant matter and plant-sourced food.
Their diet includes agricultural grains, fruit (especially figs), the vegetative parts and seeds of grasses, sedges and aquatic plants, and fleshy, thick underground stems.
On occasion, the goose tends to augment the diet with insects or small fishes. Spur-winged goose has an omnivorous diet.
Habitat and Distribution
The spur-winged goose can be found around other African swamps, rivers, and lakes. They have a preference for a serene expanse of riverbanks and wetlands for nesting sites.
They typically hide their large nests close to water, but they also use alternative locations. Such locations include tree holes, rock cavities, and old hamerkop.
They are also known to inhabit other animals’ habitats such as the African fish eagle, social weaver, aardvark, and even termites. The spur-winged goose tends to choose a tree-nest situated close to the ground at heights between 8 and 39 inches high.
Trees usually chosen for nesting are usually 10 to 13 feet tall.
The mating season for the spur-winged goose is flexible across the territorial range. Usually, it can take place at any time of the year. In northern Africa, mating typically takes place from August to December.
In eastern Africa, it occurs from January to June, and in southern Africa, from August to May. The male and female spur-winged geese’s partnership does not last long since the male usually leaves once the offsprings have hatched.
Before his departure, he gives some attention to securing the territory used for breeding. The female goose lays between 7-14 eggs per brood, and incubation usually lasts for about 31 days before they are hatched.
A case of eggs numbering up to 27 have been hatched, but it was thought to be from more than one female goose. The female departs from the nest every early morning or late afternoon to feed. During her absence, the eggs are left covered with her down to keep them warm and secure.
The offsprings can leave the nest as soon as they are hatched. The mother only shows parental care. Once they reach 85 days old, they would have grown their feathers for flight, and they can fly as early as 100 days old.
Some threats to their population include the likelihood of being shot by farmers due to their feeding on grains used for agriculture. They tend to get hunted because of their size.
The spur-winged goose managed to extend its density and distribution due to dams’ construction and increased food supply. Nevertheless, their conservation status is classified as “Least Concern”.