#whio

Lovely weekend at deer camp 🦌

By Bernard Spragg, in the Public Domain

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Name: Hymenolaimus malachorhynchos

Status: Extant

First Described: 1843

Described By: Gray

Classification: Dinosauria, Saurischia, Eusaurischia, Theropoda, Neotheropoda, Averostra, Tetanurae, Orionides, Avetheropoda, Coelurosauria, Tyrannoraptora, Maniraptoriformes, Maniraptora, Pennaraptora, Paraves, Eumaniraptora, Averaptora, Avialae, Euavialae, Avebrevicauda, Pygostylia, Ornithothoraces, Euornithes, Ornithuromorpha, Ornithurae, Neornithes, Neognathae, Galloanserae, Anseriformes, Anseres, Anatoidea, Anatidae

Hymenolaimus, otherwise known as the Whio (pronounced Fee-oh), is an endangered cuk from New Zealand (so, that explains why it’s endangered). The Whio is a rather taxonomically distinct bird, though it’s probably closest to the dabbling ducks. This bird weighs up to 1 kilogram, though usually its a bit less than that. They are dark grey with some greenish color on the heads, with blueish top plumage, and chestnut-speckled chests. They also have pale bills. They look at least a little different depending on whether they’re from the North or South Island populations, but they aren’t different subspecies. They nest in hollow logs and small caves; and believe that and its endangered status, they are rather rare ducks. 

By World Playground, CC BY-SA 3.0

They don’t fly often, but they are powerful swimmers in strong currents. They feed on aquatic invertebrates, especially caddisfly larvae. They nest in August and October, with the female incubating the nest and the male standing guard, though they are at risk from spring floods, making breeding an often difficult endeavor. Currently, there seem to be at maximum 3,000 ducks left in the wild, and its localized population on an ecologically overturned island increases their vulnerability. Conservation efforts, including a five-year management plan, are underway. 

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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.

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.

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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 our 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!

Tom with his long lens zooming in on a pair of whio

Brolly and camera in hand on the lookout for whio

Teamwork! “Lovely weather for ducks…” 😀

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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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Population

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.

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.

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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

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Final Challenge: Spot the Whio

Believe it or not, there are two whio in this photo:

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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 – http://www.doc.govt.nz/whio (Retrieved 21 January, 2018)

Department of Conservation Website – Educational Resources: Whio Fun Facts Posters – http://www.doc.govt.nz/get-involved/conservation-education/resources/blue-duck-whio-fun-facts-posters/ (Retrieved 21 January, 2018)

IUCN Redlist – Hymenolaimus malacorhynchos –http://www.iucnredlist.org/details/22680121/0 (Retrieved 21 January, 2018)

New Zealand Birds Online Website – Blue Duck – http://nzbirdsonline.org.nz/species/blue-duck (Retrieved 21 January, 2018)

Whio Forever Project Website – http://whioforever.co.nz/ (Retrieved 21 January, 2018)