Family Ducks, Geese, Swans (Anatidae)

Endangered

Hawaiian Duck (Anas wyvilliana)


Taxonomy

French: Canard des Hawaï German: Hawaiistockente Spanish: Ánade hawaiano
Taxonomy:

Anas wyvilliana

P. L. Sclater

, 1878,

Hawaiian Islands

.

Hitherto included within A. platyrhynchos. Genetic data suggest that it is descended from a hybridization event between A. platyrhynchos and A. laysanensis occurred around the Pleistocene–Holocene boundary#R. Probable unstable hybrids of A. superciliosa and present species, A. laysanensis or A. platyrhynchos, found on some Micronesian islands, have been considered a different species, Mariana Duck (A. oustaleti). Superficially resembles A. fulvigula, but differs in blue-green vs green-blue speculum (2); broad white lower edge to speculum (1); white eyering (2); streaking below less pronounced, heavy and continuous (ns[1]); smaller in size, mean male weight 638 g vs 1043 g in fulvigula and 1028 g in diazi, resulting in a “44% decrease in body mass and in dimensions”#R (3). Monotypic.

What do (1) and (2) mean? Learn more about the scoring system.
Distribution:

Kaua’I and Ni’ihau, in Hawaiian Is. Reintroduced on O’ahu, Hawaii (Big I) and Maui.

Descriptive notes

44–51 cm; 568–628 g. Small, dark brown dabbling duck with orange legs and narrow whitish eyering. Males of two types, both with greenish-olive bill and dark mark on culmen: ‘... read more

Voice

Considered to be less vocal than A. platyrhynchos and vocalizations regarded as higher-... read more

Habitat

Nests along streams and ditches in sugar-cane fields or near reservoirs. Recorded up to 2400 m in... read more

Food and feeding

Diet includes green algae, rice, grasses and seeds and leaves of wetland plants, as well as earthworms, dragonflies, fresh- and brackish-... read more

Breeding

Season perhaps year-round (mainly Dec–May on Kauai). In single pairs or loose groups; nest is bowl of grass lined with feathers and... read more

Movements

Generally sedentary, although some inter-island movements recorded, e.g. between Kauai and Niihau.

Status and conservation

ENDANGERED. Population estimated to number c. 2200 individuals, roughly equivalent to 1500 mature individuals, with c. 2000 on Kauai and Niihau, and c. 200 on Big I; in 1997... read more

Recommended citation

del Hoyo, J., Collar, N. & Kirwan, G.M. (2017). Hawaiian Duck (Anas wyvilliana). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from https://www.hbw.com/node/467121 on 15 December 2017).