Source: Department of Conservation
Perhaps you know your Daffy from your Donald, your Huey from your Louie and Dewey, but do you really know your ducks?
Communications and Media Advisor Krysia Nowak takes a duck-dive into the shallows for a quick wade around the ducks of Aotearoa.
This is the final episode, friends, with a focus on the fantastically fabulous whio. Found only in Aotearoa New Zealand (unless you happen to take a $10 note overseas), whio are more threatened than some species of kiwi – it’s time we showed them some love!
What’s in a name?
As Shakespeare almost once said, ‘a blue duck by any other name would still be blue’. Except these aren’t, really. At a stretch they might be a steel blue, but my personal opinion is that the name came about because ‘grey duck’ was already taken (See Ducktales Episode 1: Quacking the case on mallards and grey ducks). A more accurate name, then, is the te reo Māori ‘whio’, or ‘kowhiowhio’, said to resemble the whistling sound the males make.
Whistling you say? That’s right, no generic quacking for our whio whānau. Males have a piercing whistle, synonymous with out backcountry river soundscape, while the females utter a purring sort of growl.
Make of that what you will.
Listen here: https://www.doc.govt.nz/globalassets/documents/conservation/native-animals/birds/bird-song/blue-duck.mp3
A whitewater wonder
You may be used to ducks living on still water, perhaps gently flowing water, a pond, a stream, a lowland river. Not so the whio; they’re thrill-seekers. Instead, picture these hardy ducks on rapids we’d usually associate with rafting and adventure sports. Even the ducklings can handle strong currents with ease, thanks to their oversized ‘umbrella-like’ feet.
Whio are only distantly related to our other ducks, as they separated from other species a long time ago. They’ve specialised in this fast-flowing environment, in fact, they’re one of only four species of duck in the world adapted to live in ‘torrent’ environments!
To give an example of their specialisation, I once saw a whio family on the pond at Tongariro National Trout Centre (they pop in occasionally, a holiday from the river I guess). I had the privilege of watching one of the adult whio chasing a mallard around the pond. Swimming near each other the differences were stark – whio with their streamlined bodies racing through the water, next to the dingy-like mallard at a relaxed pace. Needless to say, the mallard ceded the pond, and the whio emerged victorious.
Clean, clear, and cold
Whio need clean, clear, cold water to survive. Well…mostly so they can eat. Visual hunters, they peruse the current and under rocks for tasty insects and worms (with a cool beak!). They can handle the occasional flood muddying the water, but permanently silty environments kill their kai, and their ability to find it.
So why clean and cold? Well not a whole lot of things like to live in pollution (except humans, apparently), and whio food is no exception. Prime whio fodder like mayflies, caddis, and stoneflies have high oxygen needs. Pollution uses up oxygen, and warm water holds less oxygen, so clean and cold is where it’s at.
Stoatally uncool
Imagine whio back before mammalian predators were introduced, when threats came from other birds like harriers and black-backed gulls. Birds are visual, and most (with a couple of notable exceptions) don’t have a good sense of smell. So, the ultimate whio defence strategy was born: look like a rock. People unfamiliar with whio spotting often fail to spot the ‘slightly animated rocks’ that betray a stealthy whio. Ducklings are a black and white combination that somehow disappears completely in the rapids.
Try and count whio ducklings on the move. Go on, I dare you.
Enter mammalian predators, like stoats, with an excellent sense of smell to tell boulder from bird. Suddenly, whio are *ahem* sitting ducks. Whio aren’t completely defenceless; they’re feisty and can often fight off predators, but they have no way to hide from predators who can sniff them out, and it’s difficult to fight a stoat and keep your eggs alive at the same time. If a stoat finds a female whio sitting on her nest, it’s only a matter of time before it either kills her or drives her off and eats the eggs. All the while, the male whio is diligently watching the river and sky for threats, not realising the real threat now comes from the land (this breaks my heart).
By the time conservationists realised there was a problem, there were estimated to be less than 2500 whio left in the entire country.
Whio Forever?
So, how can we stop the decline of whio? Partner up!
If we control stoats in whio habitat, we give whio their best chance of resilience in the face of other threats like climate change. We’re pretty fortunate here at DOC to have a partnership with Genesis, and with their support we’ve been able to protect more than 1,500 kilometres of river in whio habitat in locations across New Zealand.
Stoats aren’t the only threat to whio though, many of our rivers aren’t as healthy as they used to be, so habitat loss is right up there, along with climate change. Helping to keep our rivers healthy (don’t litter, plant trees, wash your car on the grass, etc), and reducing our greenhouse gas emissions (you know the drill) are actions that can help the wider picture for fabulous whio.
Well, I’m all out of ducks, and you’ve made it to the end of the ducktales blogs; well done you! Now you get to go on and share all these new facts at your Christmas parties. You’re welcome; you can thank me by being decent to ducks:
Be decent to ducks
Be a responsible cat owner, by:
- Desexing and microchipping your cat
- Keeping your cat indoors or contained inside a ‘catio’, especially at night
- Putting your cat in a cattery when you go on holiday
- Never taking them onto public conservation land.
Be a responsible dog owner:
- This link is about dogs on beaches, but it has good advice for many natural environments: Dogs on beaches (doc.govt.nz)
- For whio it’s also important to keep dogs on a lead around rivers during nesting season (August to January)
- Hunters can request whio avoidance training alongside kiwi avoidance training for their dogs – visit https://www.kiwiavoidancetraining.nz/
Please don’t feed ducks, feeding wild birds can:
- Make them sick or make them starve because they are eating the wrong things
- Make them gather in unusually high numbers, spreading disease (we’re especially wary of this with H5N1 avian influenza spreading overseas)
- Increase their numbers at a cost to other species (e.g. mallards outcompeting pāteke on Aotea/Great Barrier Island)
- Modify natural behaviours so the birds spend more time in locations where they are at risk of pet attacks or car strike
- Increase risks to human health by increasing the concentration of bird faecal matter
Trap introduced predators at home or in your community:
