The Blue-winged Goose (Cyanochen cyanoptera) is a large goose, which is endemic to Ethiopia. It is the only member of the genus Cyanochen. Placement of this species in the waterfowl phylogeny is unresolved; while it is morphologically closest to shelducks and resembles sheldgeese in habitus, mtDNA 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, perhaps together with Hartlaub's Duck. Interestingly, the wing color pattern - the best morphological indicator of evolutionary relationships in waterfowl - is nearly identical in these two species, and very different from any other anatid.
This is a stocky 60-75 cm grey-brown bird with a slightly paler head and upper neck. It has a small black bill and black legs. In flight, this species shows a pale blue forewing. Sexes are similar, but immature birds are duller.
The Blue-winged Goose is a quiet species, but both sexes may give a soft whistle; it does not honk like Anserini (true geese).
The habitats of the Blue-winged Goose are primarily rivers, freshwater lakes, swamps, freshwater marshes, water storage areas, and subtropical or tropical high-altitude shrubland or grassland. It feeds by grazing, and is apparently largely nocturnal, loafing during the day. It can swim and fly well, but this terrestrial bird is reluctant to do either, and is quite approachable. It forms flocks outside the breeding season.
It breeds by mountain lakes and streams. This little-known species is believed to build a lined nest amongst grass tussocks, and to lay 6-7 eggs.
It is threatened by habitat loss. Formerly classified as a Near Threatened species by the IUCN, new research has shown it to be rarer than it was believed. Consequently, it is uplisted to Vulnerable status in 2008.