Pacific Black Duck

The Pacific black duck, Anas superciliosa, is a dabbling duck of notable sociability, found across a broad range in the Pacific region. It is characterized by its dark body and paler head adorned with a dark crown and facial stripes. When in flight, one can observe its green speculum and the pale underside of its wings. Both sexes exhibit similar plumage, and size varies from 54 to 61 centimeters, with males generally larger than females. Some island populations are smaller and darker.

Identification Tips

To identify the Pacific black duck, look for its dark body contrasted with a lighter head, marked by a distinctive dark crown and facial stripes. In flight, the green speculum is a key feature, along with pale underwing. The species exhibits little sexual dimorphism, making size and behavior more reliable for distinguishing males from females.

Habitat

This duck favors a variety of wetland habitats, demonstrating adaptability in its choice of nesting and feeding grounds.

Distribution

The Pacific black duck is widespread, inhabiting much of Indonesia, New Guinea, Australia, New Zealand, and numerous islands in the southwestern Pacific. It extends as far north as the Caroline Islands and as far east as French Polynesia. In New Zealand, it is commonly referred to as the grey duck or by its Maori name, pārera.

Behaviour

The Pacific black duck is known for its gregarious nature. It shares nesting habits with the mallard and is capable of quacking, a vocalization more commonly associated with its relatives. The female's quack is a raucous, descending sequence.

Breeding

Breeding behavior includes nesting in tree holes, occasionally using old corvid nests, and sometimes nesting on the ground. The female incubates a clutch of 8–10 pale cream eggs for 26–32 days. Ducklings are precocial and leave the nest upon drying, under the care of the female until they achieve flight at approximately 58 days old.

Diet and Feeding

The diet of the Pacific black duck is primarily vegetarian, consisting of seeds from aquatic plants. This is supplemented by small crustaceans, molluscs, and aquatic insects. The duck commonly feeds by dabbling, submerging its head and neck while upending in the water. It may also forage on land in moist grassy areas.

Conservation status

The Pacific black duck is currently classified as Least Concern by the IUCN. However, it has experienced significant declines in New Zealand and on several Australian islands due to competition and hybridization with the introduced mallard. This has led to concerns about the potential loss of the species' identity and the rise of hybrid populations.

Similar Species

The Pacific black duck may be confused with the mallard, especially where their ranges overlap and hybridization occurs. The now-extinct Mariana mallard was likely a result of such hybridization. Observers should note the Pacific black duck's distinctive facial markings and green speculum for accurate identification.