The blue-winged goose (Cyanochen cyanoptera) is a waterfowl species which is endemic to Ethiopia. It is the only member of the genus Cyanochen.
Relations
The relations of this species among the waterfowl was long unresolved. It is morphologically close to shelducks, and particularly the South American sheldgeese, which have 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 pattern, a good morphological indicator of evolutionary relationships in waterfowl, is similar in these two species, and different to most other waterfowl (though shared by species in the genus Spatula). More recent genetic evidence has confirmed this clade, and further points to their belonging to a larger group of diving duks, with their closest relatives being a clade containing marbled duck (Marmaronetta angustirostris), white-winged duck (Asarcornis scutulata), and the widespread genera Netta and Aythya; with these, they are next closest to Australian wood duck (Chenonetta jubata) in Australia, blue duck (Hymenolaimus malacorhynchos) in New Zealand, and the pantropical comb ducks (Sarkidiornis).
Description
It is a stocky grey-brown goose-like bird about long with a slightly paler head and upper neck. It has a small black bill and black legs. Standing birds look fairly dull, grey and dirty white, sometimes showing the blue along the edge of the wing. The sexes are similar, but immature birds are duller. The plumage is thick and loose, an adaptation to the cold of the Ethiopian highlands.