The New Zealand Whio or Blue Duck
A unique duck found only on white water New Zealand rivers
New Zealand is a small country, and the vast majority of its native species are unique and endangered. The endemic ducks of New Zealand are no exception. The Whio (Blue Duck) and the Pateke (Brown Teal) are the two rarest waterfowl species in the world.
The Blue Duck (Hymenolaimus malacorhynchos) is very unique, and has no close relatives at all. Like many New Zealand species, it represents an early evolutionary stage. It has since found itself a unique white water niche, and now has distinct behavioural and anatomical attributes.
It is one of only three ducks in the world that can live constantly on such fast moving water, where it must paddle constantly with its large feet to remain in one place. These feet are eceptionally large and webbed, even in ducklings, and the babies can swim the rapids from their first day!
It isn't that well known, but has appeared on a limited edition postage stamp, and of course, the New Zealand ten dollar note has a picture of the Whio on the back!
Scientific Classification & Names
Blue Duck / Whio
mountain duck, torrent duck or whistling duck
Conservation of the Blue Duck
The Department of Conservation is running a captive breeding recovery program, and Auckland Zoo has two pairs of the ducks, which produce eggs every year or so to be raised as part of the conservation effort. They can only keep one pair on display, though because they are highly territorial, and will chase off rival ducks. This means that they have to have a large section (up to a kilometre) entirely to themselves, with a fast stream running through - not easy to set up in captivity
- Doc threat classification: "Nationally Vulnerable" (second highest level in New Zealand)
- International Union of Conservation for Nature (IUCN) threat classification: "Endangered"
Whio Awareness Month: since 2011, Genesis Energy, Department of Conservation, Forest and Bird and The Central North Island Blue Duck Trust have collaborated to raise awareness about the Whio and support captive breeding projects. They run a Whio Awareness Month in March.
Blue Duck Recovery Efforts from the Department of Conservation
Population and Distribution
The fossil record indicates that they used to live throughout New Zealand. Today, they are restricted to the rivers of Urewera, East Cape and the central North Island and along the West Coast of South Island from Nelson to Fiordland.
Currently, there are an estimated 2,000 and 3,000 individuals; about 600-700 pairs in major island.
Unfortunately, the fragmented populations have difficulty interbreeding, and the small local populations tend to have far more males than females (due to predation on the nesting mothers).
Conservation and bird websites that have more information about the Whio
- Whio Forever Project | Whio Forever
The main website of the Whio recovery project.
- Blue duck/whio - Department of Conservation
Information about the Whio and conservation efforts, along with videos and fact sheets from the official Department of Conservation.
- Whio, the blue duck - New Zealand Birds
Whio, blue duck, Hymenolaimus malacorhynchos, found in New Zealand Birds' bird gallery section, includes general information about the bird, taxonomy, description, where to find them and other useful and interesting information.
Lifestyle and Appearance
A Bit About Their Behavioural and Physical Features
The Maori name, Whio (pronounced 'phee-oh') is based on the male's shrill whistling cry, which carries well over noisy white water. The female has a more guttural, rattling call.
They are fairly large ducks, reaching 53cms in length, and very broad. The males are larger, at 1000 grams, and can live for up to twelve years. The females don't live as long, and only reach 750-800 grams.
Highly camouflaged, it can be very difficult to spot as they sit around pretending to be rocks (although it isn't very wary, not having evolved around predators that can smell it out easily)
They feed by putting their head underwater and browsing around for insects. To protect their bills from being bashed around in the rapids, they have a special fleshy lip on the end of it, protecting the tips.
They tend to hide during the day, and are more active in the mornings and evenings.
They eat aquatic insect larvae, and - unlike other ducks - don't leave the river to find other food.
Breeding and Habitat
They can mate for life, and the pairs stick together to raise the duckling broods, and keep them together on the river, which isn't easy. The nest between August and October, laying clutches of 5-9 eggs, which are incubated for 35 days. While the ducklings can swim straight away, they can't fly for about seventy days - the Blue duck isn't much of a flier anyway. This often ties in with the start of the moulting period (between December and May).
It is difficult to reintroduce to the wild, as the territory it needs is very specific - the same reason that it is now so endangered. Along with introduced predators, the Whio is running out of clean, fast flowing mountain streams in forested areas to live on. They are a reliable sign that a river is healthy and thriving, and contains plenty of aquatic insects. They do better on lower rivers, and is appears that they have been pushed up to the headwaters by habitat loss.