The Ducks Who Surf Rapids: New Zealand’s Endangered Whio

A Caravanning Trip in the Rain

Despite the weather forecast promising us a very rainy weekend, nothing was going to deter us from heading out. Mum and Dad’s caravan was stocked with the essentials, mine and Tom’s cameras were packed, we all had our raincoats and gumboots, so off we set up the windy Parapara road towards Ruatiti Domain.

Hymenolaimus malacorhynchos [WHIO] Ruatiti, New Zealand 05-01-18 (24)
The Manganui‑o‑te‑Ao River viewed from the bridge on the way to Ruatiti Domain

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Ruatiti Domain is a free campsite in the Ruapehu District. It lies at the confluence of the Manganui‑o‑te‑Ao River and the Ruatiti Stream 240m above sea level. The domain is an absolute treasure and a wonderful place to explore the outdoors.

Hymenolaimus malacorhynchos [WHIO] Ruatiti, New Zealand 05-01-18 (22)
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Most excitingly for us, though, was the fact that a number of New Zealand’s endangered whio call this place ‘home’.

All of the photos in this post are from our trip away. During our first sighting, we saw three whio on the river. During our second sighting the following day, we saw two. We were very happy campers!

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New Zealand’s Endangered Whio (Hymenolaimus malacorhynchos)

Whio, sometimes called the Blue Duck, is a species of waterfowl endemic to New Zealand. The species is the only member of its genus and has no close relatives. Their isolation in New Zealand means that they have some very unique anatomical and behavioural features.

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There are estimated to be less than 3,000 individuals left, making them a nationally vulnerable species which face a risk of becoming extinct. They are rarer than many species of kiwi!

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Habitat and Diet

Whio need clean, fast flowing streams in the forested upper catchments of rivers, low sediment loadings, stable banks and overhead canopy cover. They nest in hollow logs, small caves and other sheltered spots.

Hymenolaimus malacorhynchos [WHIO] Ruatiti, New Zealand 05-01-18 (2)
The Manganui‑o‑te‑Ao River viewed from just below our campsite in Ruatiti Domain

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As their diet consists almost entirely of aquatic invertebrates, they require habitat with diverse invertebrate communities.

Whio have a unique adaptation to aid them in feeding: They have special soft, rubbery ‘lips’ on the end of their bill that allow them to scrape insect larvae off rocks. The lips also help protect their bill from damage. They are the only duck to have this adaptation.

On the rare occasion, whio will also eat berries and the fruits of shrubs.

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Whio are a key indicator of healthy rivers and streams. The more breeding pairs of whio, the healthier the river.

The Ducks Who Surf Rapids

Whio are one of the few waterfowl species worldwide that live year round on fast-flowing rivers. Even whio ducklings are self-reliant and capable of battling strong currents from the moment the hatch.

We loved watching them ride the waves, easily navigating the rain-swollen river with each paddle, dive and leap. Check out the photos below… just look at them go!

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Threats to Whio

The main threats whio face are habitat loss, predation, and disturbance. Weather events, such as flooding, also have an impact on their populations.

Even on our own walks through the area, we could see that much of the water’s edge was unfenced farmland. If you recall what I wrote above about the habitat they require, you know that this ticks none of the boxes.

Hymenolaimus malacorhynchos [WHIO] Ruatiti, New Zealand 06-01-18 (30)
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As for predation, the main culprits are introduced stoats, feral cats, pet dogs that aren’t on a leash, ferrets, and even possums and rats.

Stoats are the whio’s greatest danger as they attack females on the nest, steal eggs, and take young ducklings from the river’s edge, finding them with their great sense of smell.

The time when whio are most vulnerable to attacks is during the late summer moult period when they are flightless.

In fact, in unmanaged areas, there is a very low survival rate. See these rather depressing numbers from the Department of Conservation:

In Te Urewera we found 90% of nests failed in an area without predator control. Of the females, 46% were killed during the moult period when they retreated up small side stream to avoid disturbance.

In the Ruahines and in Taranaki, over 60% of the fledged juveniles died in areas outside of management. From a sample of 154 whio deaths recorded between 1989-2008, 89 were linked to predators (58%), 24 natural deaths, 22 human causes, and 19 were unknown. Stoats were the cause of 79 of the 89 predator deaths.

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How Can You Help?

Here are a few key tips from the Department of Conservation about how you can help whio:

  • Even though whio often act unafraid, give them space and watch them from a distance
  • Keep the waterways and the river environment clean – take out what you bring in
  • Volunteer to control predators and restore bird habitats
  • Support riparian planting and waterway protection in your area
  • If visiting a waterway, leave your dogs at home or keep them on a leash
  • Don’t drive on riverbeds, or keep to formed tracks if you have to

If you do see whio, the Department of Conservation would love to know! Just contact your closest DOC office and give them the following information:

  • Essential: Date, location, and number seen
  • If possible: Information about whether they are a pair, their sex (males whistle and females growl), age (juvenile or adult, size of juveniles), and what they were doing

Hymenolaimus malacorhynchos [WHIO] Ruatiti, New Zealand 05-01-18 (21)
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Final Challenge: Spot the Whio

Believe it or not, there are two whio in this photo. Can you spot them?

Hymenolaimus malacorhynchos [WHIO] Ruatiti, New Zealand 06-01-18 (27)
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Click here to reveal the answer.

Talk about camouflage! Whio definitely know how it’s done.

References and Further Reading

Department of Conservation Website – Whio –
(Retrieved 21 January, 2018)

Department of Conservation Website – Educational Resources: Whio Fun Facts Posters –
(Retrieved 21 January, 2018)

IUCN Redlist – Hymenolaimus malacorhynchos
(Retrieved 21 January, 2018)

New Zealand Birds Online Website – Blue Duck –
(Retrieved 21 January, 2018)

Whio Forever Project Website –
(Retrieved 21 January, 2018)

9 Comments Add yours

  1. blhphotoblog says:

    Brilliant, great images. It’s sad to hear introduced non-native species are causing such damage, will we ever learn? Brian

    Liked by 1 person

    1. Thank you, Brian. 🙂

      As a country that had no native land mammals (except for a few species of bats) until humans arrived, so many of our native species are either extinct or having a very hard time! Many of them would not be around much longer without predator control.I certainly hope we learn…!


      Liked by 1 person

  2. Interesting post. Here’s hoping numbers will start to build again.

    Liked by 1 person

    1. Thank you, Helen! Yes, I hope so, too! 🙂



  3. Wendy says:

    Thank you for bringing this to people’s attention. Kiwi get a lot of attention and everyone is aware of their plight but so many of our other critters are in danger of quietly disappearing because they lack a voice.
    I can’t help remembering a statement I read some years ago that 95% of fantail chicks were predated in the nest. Imagine losing the fantail. Imagine losing any more species when it’s in our power to save them. Keep up the good work.

    Liked by 1 person

    1. Thank you, Wendy! 🙂

      You’re right, many vulnerable species often don’t get the publicity and awareness they need – especially the ones that don’t fall in the cute+fluffy category! After all, we can only care about what we know about.

      I just read this article on the fantail: Quite upsetting! Although, the writer does mention that fantail populations have most likely increased in the last 150 years. I’ve just checked out DOC’s website to see why this might be the case. Here’s what they say:

      “The fantail is one of the few native bird species in New Zealand that has been able to adapt to an environment greatly altered by humans. Originally a bird of open native forests and scrub, it is now also found in exotic plantation forests, in orchards and in gardens. At times, fantails may appear far from any large stands of shrubs or trees, and it has an altitudinal range that extends from sea level to the snow line.

      Cats, rats, stoats and mynas are as great an enemy to fantails as they are to other native birds. Of all the eggs and chicks fantails produce, only a few survive and grow up.

      However, the secret to fantails’ relative success compared to other native birds is their ability to produce lots of young. Some chicks are therefore likely to escape predation and populations can bounce back quickly after a decline.

      Its broad diet of small insects also makes the fantail resilient to environmental change, because certain insect populations increase in disturbed and deforested habitats” (

      Interesting stuff!



      1. Wendy says:

        It’s a tragedy alright, Emma. Like the DOC video showing a cat in a karearea nest, makes you cry. Thank goodness for good people like you. 🙂

        Liked by 1 person

  4. Pleased to make the acquaintance with this handsome ducks. Thank you for the introduction. I wish them well.

    Liked by 1 person

    1. Zoomology says:

      Thank you very much, Tanja! I’m glad we could introduce you. 😀 We shall pass on the well wishes next time we see them on the river! ❤


      Liked by 1 person

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