[order] ANSERIFORMES | [family] Anatidae | [latin] Cyanochen cyanoptera | [authority] Ruppell, 1845 | [UK] Blue-winged Goose | [FR] Ouette a ailes bleues | [DE] Blauflugel-Gans | [ES] Ganso Aliazul | [NL] Blauwvleugelgans
The Blue-winged Goose (Cyanochen cyanoptera) is a waterfowl species which is endemic to Ethiopia. It is the only member of the genus Cyanochen. The relations of this species among the waterfowl is unresolved. It is morphologically close to shelducks, and particularly the South American sheldgeese, which have highly similar courtship displays. However, mitochondrial DNA sequence analyses of the cytochrome b and NADH dehydrogenase subunit 2 genes indicates that it might belong to a very distinct and ancient “duck” clade, together with Hartlaub’s Duck, another African species of uncertain affinities. The wing color pattern, a good morphological indicator of evolutionary relationships in waterfowl, is similar in these two species, and very different from any other waterfowl
The blue-winged goose can be a hard bird to spot when it is on the ground, a grey-brown shape against a brown, marshy background; but when this bird takes off, the large powder-blue patch on its wings makes it unmistakable. Both male and female blue-winged geese are very similar in appearance, other than the female is typically smaller. Both sexes have brownish-grey plumage, which is darker on the upperparts and paler on the forehead and throat. The feathers on the breast and belly have pale centres, resulting in a mottled appearance, and the tail, legs and bill are black (2). The feathers of the wing have a faint metallic green sheen and the upper wing coverts are pale blue, giving this species its name. Juvenile blue-winged geese are similar in appearance to the adults, other than their wings lack the green gloss.
Africa : Northeast. Cyanochen cyanoptera is endemic to the highlands of Ethiopia
The species often breeds in open Afro-alpine moorland. The species occurs on the banks of highland rivers and lakes with adjacent meadows of short grass. It also inhabits the edges of highland lakes, marshes, bog pools, swamps and streams with abundant grassland surroundings. It is rarely found in overgrown areas and does not venture into deep water. In the central parts of its range it occurs most commonly at altitudes of 2000-3000m in areas with waterlogged black cotton-soils (vertisols). At the northern and southern extremities of its range it occurs at higher altitude where the substrate is granitic and the grasses coarser and longer.
During the mating season the male blue-winged goose struts his stuff with his head bent over his back exposing his blue wing patch for her to inspect. The courtship and breeding takes place by lakes and streams in the mountains and they build their nests in among grass tussocks. The female lays between 4 and 7 eggs which are incubated for about 4 to 5 weeks. Je you fledge after another 3 monts. The species is sexually mature at the age of 3.
The species is primarily herbivorous, grazing on grasses, sedges and other herbaceous vegetation. However it is also reported to take worms, insects, insect larvae, freshwater molluscs and even small reptiles.
copyright: Josep del Hoyo
This species has been uplisted to Vulnerable owing to recent data which indicates that it has a small population which is declining owing to the drainage and degradation of its highland wetland habitat.
It is not threatened by hunting (as, for religious reasons, it is not eaten). However, it is now almost certainly under pressure because of the rapidly expanding human population and resulting drainage and degradation of wetlands and grasslands, and increased levels of disturbance. Agricultural intensification (privatisation) and droughts are also possible threats.
This species is mostly sedentary but demonstrates some small-scale seasonal altitudinal movements. It breeds during the dry season months of March – June8 during which time it occurs in dispersed single pairs or small groups. Little is known about breeding behaviour due to the species’ nocturnal habits. It moves to lower altitudes during the wet, non-breeding season8, where it sometimes congregates in relatively large, loose flocks of 50-100 individuals.