Hawaiian Duck

Hybridisation, rather than direct persecution, is the central conservation problem facing the Hawaiian Duck (Anas wyvilliana). Endemic to the Hawaiian Islands, it closely resembles a female Mallard - mottled brown, with an iridescent blue-purple speculum bordered in white and an orange bill - and interbreeds readily with feral Mallards, eroding the genetic integrity of the native population. Males may show a faint green gloss on the head, far weaker than in the Mallard; females carry a pale buff supercilium. The birds use freshwater marshes, rivers, reservoirs and taro fields on Kauai and other islands, nesting in dense vegetation near water and laying nine to thirteen eggs. Recovery work centres on limiting contact with feral Mallards.