Hartlaub's duck (Pteronetta hartlaubii) is a dark chestnut-coloured duck of African forests. Formerly included in the paraphyletic "perching duck" assemblage, it was later moved to the dabbling duck assemblage.
Taxonomy
Analysis of mtDNA sequences of the cytochrome b and NADH dehydrogenase subunit 2 genes suggests that it belongs into a distinct clade together with the blue-winged goose (Cyanochen cyanoptera), another African species of waterfowl. 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
left|thumb|Pair of Hartlaub's ducks in Cameroon
On average, Hartlaub's ducks range from long. It is monotypic, with no subspecies accepted. Juveniles have feathers with pale tips on their breast and abdomen. The adult plumage is red-brown overall with a black head with or without white marks on the crown; adult plumage is fully developed after six months. The amount of white on each duck's head varies. Adult males weigh between , and have reddish-brown eyes; they are more likely to have extensive white on the crown. The females weigh between , and rarely have any white on their heads; they have dark red eyes. Both sexes have a blue patch on their wing that distinguishes them from most other waterfowl. During mating season, the base of the male's bill will enlarge.
Distribution
Hartlaub's duck is resident in equatorial West and Central Africa, from Guinea and Sierra Leone east through Nigeria to South Sudan, and south to Gabon, Congo and Zaire.
Hartlaub's ducks reside in swampy marshes, tropical forests, savanna areas, rivers, and streams. In Liberia, they live in mangroves. However, they will only gather in flocks in Liberia from January to May. Year-round, they will live in parts of central western Africa, including the Democratic Republic of Congo and Cameroon.