25-5-2019 MANA POOLS, ZIMBABWE - SPUR WINGED GOOSE (Plectropterus gambensis)

The Spur-winged Goose, Plectropterus gambensis, is a striking waterbird endemic to Sub-Saharan Africa. It is a member of the Anatidae family, which encompasses geese and shelducks, but has evolved unique anatomical features that distinguish it from its relatives, placing it in its own subfamily, Plectropterinae. This species is one of the largest true waterfowl in Africa and is considered the world's largest goose by average weight, with males being notably larger than females.

Adult Spur-winged Geese measure between 75 to 115 cm in length and weigh approximately 4 to 6.8 kg, with some individuals reaching up to 10 kg. They boast a wingspan ranging from 150 to 200 cm. The plumage is predominantly black with a white face and prominent white wing patches. Their long legs are tinged with pinkish red. The male is distinguishable by a larger red facial patch extending from the red bill and a knob at the base of the upper mandible. The subspecies P. g. niger, found south of the Zambezi River, has a smaller white belly patch and can appear almost entirely black from a distance.

The Spur-winged Goose favors open grasslands adorned with lakes, seasonal pools, rivers, swamps, and river deltas. It typically inhabits large inland rivers and lakes, avoiding saline lakes and arid zones. It can be found at elevations up to 3,000 meters in eastern Africa.

This species is widespread across Sub-Saharan Africa, with the subspecies P. g. gambensis and P. g. niger occupying different regions. P. g. niger is particularly prevalent south of the Zambezi River.

The Spur-winged Goose is a social bird, often found in small flocks of up to 50 individuals. It spends the middle part of the day resting by water and feeds by grazing on plant matter, occasionally supplementing its diet with small fish or insects. The species is known for its aggressive behavior towards other waterfowl during the breeding season, using the spur on its wings in conflicts.

The Spur-winged Goose is generally a quiet species. Males may emit a soft bubbling 'cherwit' when taking flight or feeling alarmed. Both sexes may produce other inconspicuous calls during breeding displays or when alarmed.

Breeding seasons vary across their range, with northern populations breeding from August to December, eastern Africa from January to June, and southern Africa from August to May. Nests are large and usually concealed in vegetation near water, but they may also use tree holes, cavities in rocks, or even the nests of other birds.

The diet is predominantly plant-based, including grasses, sedges, aquatic plants, grains, fruits, and tuberous crops. They may also eat small fish or insects.

The Spur-winged Goose is classified as Least Concern by the IUCN. The main threats include habitat destruction and unregulated hunting. A survey in western Africa estimated a population of 10,000 individuals, with many found in the Niger basin. The species is protected under the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA).

25-5-2019 MANA POOLS , ZIMBABWE - SPUR WINGED GOOSE (Plectropterus gambensis)

The Spur-winged Goose is Africa's largest waterfowl, known for the sharp spurs on its wings used for defense. These large, black-and-white geese are found in wetlands and floodplains across Sub-Saharan Africa, and they have a unique diet that can include toxic blister beetles, making the birds themselves potentially poisonous to predators, including humans. They are omnivorous, feeding on both plants and small animals, and can cause damage to crops due to their preference for grains and fodder. Physical characteristics and defense They are the largest waterfowl species in Africa, with some males weighing over \(10\) kg.Their appearance is mostly black with metallic green glossing and white on the face and belly, and they have pinkish-red legs and bills.The "spur" is a sharp, hard projection on the bend of each wing, which they use aggressively for defense and territorial disputes with other birds. 

Habitat and diet They inhabit a wide range of wetland habitats, such as rivers, lakes, swamps, and floodplains, but also frequent agricultural fields.They are predominantly herbivores, feeding on seeds, grasses, and crops, but will also eat insects and small fish.Some populations are potentially poisonous due to their diet of blister beetles, which contain the toxin cantharidin. Behavior and breeding Spur-winged Geese are often gregarious and can form large flocks, though they are shy and wary.They are monogamous and their breeding season varies depending on the region.Nests are typically built in vegetation near water, but they will also use tree holes, rock cavities, or termite mounds.Females incubate the eggs and care for the young, while males may stay to defend the area. 

24-5-2019 MANA POOLS, ZIMBABWE - SPUR WINGED GOOSE (Plectropterus gambensis)

The spur-winged goose (Plectropterus gambensis) is a large, Sub-Saharan African waterbird in the family Anatidae, which includes geese and shelducks. However, P. gambensis developed unique environmental adaptations, which resulted in the evolution of several anatomical features that are not shared with other anatids; thus, the species has been classified one step further into its own subfamily, the Plectropterinae.

Adults are 75–115 cm (30–45 in) long, and weigh an average of 4–6.8 kg (8.8–15.0 lb) (rarely up to 10 kg (22 lb)), with ganders (males) being noticeably larger than the geese. The wingspan can range from 150 to 200 cm (59 to 79 in). One source claims the average weight of males is around 6 kg (13 lb) and the weight of females is around 4.7 kg (10 lb). However, 11 individuals that were banded in South Africa, were found to average only 3.87 kg (8.5 lb), with a range of 2.4 to 5.4 kg (5.3 to 11.9 lb). Another South African-based study found 58 males weighing an average of 5.52 kg (12.2 lb) and measuring 98.1 cm (38.6 in) in total length; meanwhile, 34 females averaged 3.35 kg (7.4 lb) in weight and 84.2 cm (33.1 in) in total length.[8] Among standard measurements, the wing chord is 42.5 to 55 cm (16.7 to 21.7 in), the bill is 5.7 to 6.4 cm (2.2 to 2.5 in) and the tarsus is 5.7 to 12 cm (2.2 to 4.7 in). 

They are among the largest true African waterfowl (besides the wading Goliath heron) and are, on average, the world's largest "goose", although in average weight, their size is at least rivaled by the Cape Barren goose. Spur-winged geese appear to be more closely allied to shelducks than "true geese" such as those from the Branta and Anser genera. They are mainly black, with a white face and large white wing patches. The long legs are pinkish red in colour. 

Some populations of the spur-winged goose are toxic. Populations that have a diet that includes significant quantities of blister beetles are poisonous. The poison, cantharidin, is held within the tissue of the bird resulting in poisoning of those that eat the cooked goose. A dose of 10 mg of cantharidin can kill a human.

This species often occurs in open grasslands with lakes, seasonal pools, rivers, swamps and river deltas. Large inland rivers and lakes are perhaps most commonly inhabited, with saline lakes and upland areas generally being avoided, although the species can occur to an elevation of 3,000 m (9,800 ft) in eastern Africa. It is also absent from arid zones.