Maori name Whio (fee-o)
Scientific name Hymenolanimus malacorhynchos
Relatives duck, goose and swan; no close relative anywhere in the world
Average Lifespan 6 - 12 years
Habitat endemic to New Zealand; bouldery fast flowing forested mountain rivers; rivers must have stable banks and high water quality
Features streamlined head and large webbed feet for swimmimg in fast moving water; specialised bill to scrape insect larvae off rocks; yellow eyes
Behaviour active during early morning and dusk; hides during the day; powerful swimmers even in white water; reluctant to fly
Size 53cm long, 1kg (male)
53 cm long, 800g (female)
Voice "whio" whistle (male); rattling growl (female)
Diet exclusively aquatic insect larvae
Threats loss of suitable riverine habitats; decreased flow/water quality of rivers; human disturbance; competition for food with introduced trout; predators including stoats, possumes, cats & dogs
Reproduction strong pair bonding; female lays 4-7 eggs and incubates them for 35 days; river-side nests are prone to spring flooding
In recent years numbers of whio in the south east Paparoa's have plummeted and now there is only a single breeding pair + one individual remaining in the Moonlight ck and no known resident birds in the Blackball ck.
Even with predator trapping these remaining whio are under considerable threat of localised extinction.
The trapping programme makes it an ideal site for re-establishing a whio population through Operation Nest Egg but the trapping must be maintained.
All trapping is done by volunteers from the local community.
The Whio is classified as endangered as it has a very small and severely fragmented population that is undergoing a continuous decline. The Whio on the International Union for the Conservation of Nature and Natural Resources IUCN Red List of Threatened Species.
The Whio appears on the NZ 10 dollar note.
Why has the Whio no close relatives?
what makes them unique - live year round on fast-flowing rivers
How many Whio are there?
There is a population of approximately 1200 birds which is declining.
Department of Conservation Whio / Blue Duck
Birdlife International Blue Duck Fact Sheet
Arkive Images