Hymenolaimus malacorhynchos
Silhouette: Sheatherius · PhyloPic
In 3 days ~30% in a week ~50%
The blue duck (Hymenolaimus malacorhynchos) or whio is a member of the duck, goose and swan family, Anatidae and is endemic to New Zealand. It is the only individual species belonging to the genus Hymenolaimus. Its closest relatives are the ducks in the genus Sarkidiornis.
First seen and recorded by the British explorer, James Cook in his second voyage to New Zealand, its scientific name was given by the German naturalist, Johann Friedrich Gmelin in 1789 and later George Robert Gray in 1843. There are two subspecies of the blue duck, one in North Island and the other in South Island. Common to both gender, its physical characteristics include yellow iris, a pale grey beak with semicircular flaps and lamellae, dark-slate grey plumage, chestnut flecked breast, dark grey webbed feet, and well developed claws. The male blue duck has a high-pitched whistle, which gave its Māori name Whio, while the female has a low-pitched rattle.
The European voyages led to more human settlement in New Zealand, causing a loss of forests, and which started the decline of Blue duck in the country. It was last commonly seen in New Zealand in the 1950s following which stoat predation caused its further population decline and limiting it to only North and South Island. Geographically, it is found in clean and stable rivers which have a medium to steep gradient. It roosts close to the undercut of river banks, and can do breeding and moulting in more wider area having tributaries and small streams.
Blue ducks have a territorial behaviour with paired ducks staying in its territory during and post-breeding season. Single males often attempt to intrude into paired blue duck territory with differing results while the juvenile ducks stay close to their catchment. It mostly feeds on aquatic invertebrate larvae such as Chironomidae and caddisfly larvae. Foraging is done by using both methods–dabbling and diving. Dabbling is more commonly used by the adult blue duck than the juvenile blue duck. Also, territorial blue duck forages on mornings and evenings, while non-territorial duck forages on midday. Paired ducks defend themselves using techniques for e.g., head-low flight, upright, head-bobbing, siphon-feeding and vocalisations. When ducklings learn to fly, they lose contact with their parent blue ducks which by then becomes flightless. In the breeding season, a clutch of 6 eggs are laid with an incubation period of 35 days. Wikipedia →
Recording0:14
New Zealand · 2024
© Oscar Dove · iNaturalist · CC BY 4.0
Recording0:31
New Zealand · 2025
© amoncarter · iNaturalist · CC BY-NC 4.0
Recording0:11
New Zealand · 2023
© Emilie & Victoria · iNaturalist · CC BY-NC 4.0
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Egmont National Park | 🇳🇿 New Zealand | |
| 2 | Fiordland National Park | 🇳🇿 New Zealand | |
| 3 | Arthur's Pass National Park | 🇳🇿 New Zealand | |
| 4 | Abel Tasman National Park | 🇳🇿 New Zealand | |
| 5 | Aoraki Mount Cook National Park | 🇳🇿 New Zealand |
| # | Zoo / Centre | Country | |
|---|---|---|---|
| 1 | Orana Wildlife Park | 🇳🇿 New Zealand | |
| 2 | Hamilton Zoo | 🇳🇿 New Zealand | |
| 3 | Pūkaha National Wildlife Centre | 🇳🇿 New Zealand | |
| 4 | Auckland Zoo | 🇳🇿 New Zealand | |
| 5 | Staglands Wildlife Reserve | 🇳🇿 New Zealand | |
| 6 | Willowbank Wildlife Reserve | 🇳🇿 New Zealand | |
| 7 | Kiwi Park | 🇳🇿 New Zealand | |
| 8 | West Lynn Garden | 🇳🇿 New Zealand | |
| 9 | Ōtorohanga Kiwi House | 🇳🇿 New Zealand | |
| 10 | Te Anau Bird Sanctuary | 🇳🇿 New Zealand | |
| 11 | Wingspan National Bird of Prey Centre | 🇳🇿 New Zealand |
With luck
About 10% of wildlife watchers report a Blue Duck sighting in Egmont National Park on a given day, based on 52 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 33rd most-seen of the 46 birds we can rate there. Over three days the chance rises to about 30%, and over a week to about 50%, if each day is a fresh chance.
June
In that month about 30% of wildlife watchers report a Blue Duck in Egmont National Park on a given day, against under 5% in January, April, July and October, the lowest months.
Between 9 am and noon
Across all the parks we cover, that three-hour window holds the most Blue Duck sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Yes
Of the 5 parks where we can rate Blue Duck sightings, Egmont National Park has the highest daily chance: about 10%. Next come Fiordland National Park (New Zealand, about 10%) and Arthur's Pass National Park (New Zealand, about 10%).
Same family: Anatidae
The closest relatives of the Blue Duck that you can see in Egmont National Park (family Anatidae, Ducks, Geese, and Swans) are Paradise Shelduck (about 30%) and Mallard (about 20%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Blue Duck is recorded against all the birds logged in Egmont National Park (52 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
