Black-headed duck (Cuckoo duck)

Heteronetta atricapilla

Koekoekseend / Kuckucksente / Hétéronette à tête noire

The Black-headed Duck is a South American duck allied to the stiff-tailed ducks in the subfamily Oxyurinae of the family Anatidae.  The Black-headed Duck is of interest as an obligate brood parasite because the females never nest and lay their eggs in the nests of other birds instead, earning it the nickname Cuckoo Duck (Koekoekseend in Dutch). The hosts are particularly the Argentine ruddy duck (Oxyura vittata), rosy-billed pochard (Netta peposaca), other ducks, coots (Fulica species) and even gulls.

This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be stable, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.

This species breeds in central Chile (Santiago to Valdivia), western Paraguay (Boquerón and Presidente Hayes) and northern Argentina (south to Buenos Aires) (del Hoyo et al. 1992, Madge and Burn 1988, Hayes 1995). It is partially migratory with southern populations moving north to Bolivia, south Brazil and Uruguay in the austral winter; northern breeding populations are largely sedentary (del Hoyo et al. 1992, Madge and Burn 1988).

Black-headed ducks are a rare species in avicultural collections and zoos.

More information: http://www.iucnredlist.org/details/100600364/0 

Above: male in winter plumage

Above: juvenile male (left) and female (right) Black-headed ducks

Above: a black-headed duckling

Above: adult female Black-headed duck

Above: adult pair Black-headed ducks in summer plumage, female in front

Above: adult female Black-headed duck

Above: juvenile Black-headed duck

Above: male Black-headed duck

Above: male Black-headed duck

Above: female Black-headed duck in the center of the photo.

Above: adult male Black-headed duck in summer plumage

Above: male Black-headed duck at the Wildfowl & Wetlands Trust, Slimbridge, UK

Above: female Black-headed duck at the Wildfowl & Wetlands Trust, Slimbridge, UK

Above: female Black-headed duck at the Wildfowl & Wetlands Trust, Slimbridge, UK