The blue duck (Hymenolaimus malacorhynchos) is an unusual duck, and a rare New Zealand endemic. It inhabits fast flowing rivers and streams and nests on the ground, usually by the river. So not only are eggs and ducklings vulnerable to stoat predation, but nests are frequently lost through flooding.
In 2002, a predator control program funded by Solid Energy was set up the Oparara Valley, where a few ducks survived. The current management program is a joint effort between the Department of Conservation and Genesis Energy, and also involves local school children in rearing juvenile ducks to be released into the catchment. From only four individuals in 2002, the population has now risen to fifty.
Blue ducks are excellent swimmers and totally at home in fast flowing water. Their upper bill ends in a broad, fleshy, overlapping tip, which allows the duck to scrape insect larvae from rock surfaces without wearing away its bill. The Maori name for blue duck is ‘whio’, the high-pitched whistling sound made by male ducks. Although not easy to find, blue ducks are generally tolerant of people, and seldom fly.