Whio Journal: Surfing the wild rivers of Tongariro

The whio, or blue duck, appears on our $10 note and the wild rivers of the back country, and not many places in between. As such, few New Zealanders know whio exist, and most will have never seen or heard one. With just 3,000 left in the wild, a partnership between Genesis and DOC called Whio Forever was created in 2011 to protect and grow the population of this national taonga. In this ‘Whio Journal’, DOC Biodiversity Senior Ranger Ali Beath walks us through the rollercoaster ride needed to undertake a whio survey (counting whio) on the wild rivers of the Tongariro District.

It’s 4.20am on a fine February morning, and I’m deep in a peaceful sleep, when the (supposedly) calming tune of the wake-up alarm on my phone blares through my dreams, dragging me abruptly into AWAKE! It can’t be that time already?

I’m heading out early today to help get some whio surveys in Tongariro Forest off the ground. I’m a Biodiversity Senior Ranger with the DOC Tongariro team, and we manage a large population of whio on the beautiful rivers of the Tongariro District in the central North Island, called the Tongariro Security Site.

Today we’re doing a whio survey by kayak on one of the larger whio rivers, a method used when it’s too difficult to undertake the survey by foot because of the terrain or length of the river. We do these whio surveys to know how big the adult population is, and how many young fledglings are present, which tells us if the season was a successful one for breeding.

Why are we doing this so early in the morning? Whio have crepuscular habits (great word that one), which means they’re mainly active in the mornings and evenings and tend to hide away in the heat of summer days. Heading out early therefore gives us the best chance of accurately counting as many whio we can. Plus, it can be a long day on the river, so it’s good to have lots of daylight hours up your sleeve so you don’t have to be rushing to get out by dark.

So, I make a strong coffee, eat some quick brekkie, and get on my way in the DOC truck.

I drive around to the north side of Mt Ruapehu to meet with Dean Flavell and kayak guide Mitch from Tongariro River Rafting. Dean is a long-time whio worker; he worked for us for many years on our whio team at DOC, and he’s helping us again today with these surveys.

We meet at the Mountain Air airstrip, near Whakapapa Village, where a helicopter will meet us shortly. We use this helicopter to fly the survey team and the kayaks into the river within the remote centre of Tongariro Forest.

This is our third attempt in as many weeks to do this survey. The first two attempts got foiled by early morning fog over the forest – too thick for the chopper. However, this morning is stunning, so we unload all the kayak gear from the truck and go through our pre-flight safety checks and safety discussion for the day.

The sun is finally coming up and the chopper and the guys are good to go! Dean and Mitch are getting flown into the confluence of two rivers ­- the Mangatepopo and the Whanganui, where the chopper pilot will skilfully put them and their gear down on a beach at the confluence.

This is an area that whio advocate Bubs Smith (Ngāti Tūwharetoa) nick-named “The Train Station”, so called because it’s got so many whio that you can sit on the rocky beach and watch multiple whio flying up and down – just like watching trains at a busy train station.

There didn’t used to be this many whio here. Whio eggs, ducklings, and adults, like so many of our native species, make good and easy meals for introduced predators, especially stoats. Tongariro Forest for years had just a relatively small population of remnant whio, hit hard from years of predation.

That all changed in 2004, when the project got funding through the Central North Island Blue Duck Trust, a trust set up by Genesis, Forest & Bird, and Te Papa Atawhai/DOC. It allowed us to purchase 600 stoat traps which we set up along three of the biggest rivers in Tongariro Forest. Crucially, it also allowed us to employ two staff whose working days were spent clearing the traps and monitoring the response of the whio population to the new trapping regime.

What a turning point that was. On the Mangatepopo River, where just eight pairs had hung in there over the years, the whio population increased to 22 pairs in the space of a few years, supported by an exceptionally clean and invertebrate-rich river system which whio need to survive.

The trapping wasn’t the only method we used to restore whio in Tongariro Forest. The Tiakina Ngā Manu programme (aerial 1080), in partnership with OSPRI (TBFree NZ), also played a huge role in the recovery of this whio population. Controversial as it sometimes is, the positive response of the whio population to both the trapping and regular Tiakina Ngā Manu operations is undeniable. In the years where Tongariro Forest had aerial 1080, the number of juveniles skyrocketed. Tiakina Ngā Manu also protects rivers that the traps can’t, simply because we can’t physically trap every single river in Tongariro Forest. Importantly, it also protects the wider rivers of the Security Site that the dispersing juveniles settle in as the population builds up.

All this has resulted in a high density and extremely productive population of whio. And like every year since 2004 (when approximately 12 pairs were found), lots of ducks are counted in the survey on the Whanganui River that Dean and Mitch do. They find 156 whio in just under 10km of river – 37 of which are breeding pairs, with the remainder being juveniles and single adults. The Tongariro Forest population continues to thrive.

In response to Covid-19, during Alert Levels 3 & 4, we weren’t able to check the trapping network, and Tongariro Forest Whio Protection Ranger, Mathew Howell, was itching to get back out into the Forest to service the traps. We all worked from home during lockdown which was a great opportunity to catch up on data entry, reports and yes – make more traps.

In many ways the last month has been a time to pause and reflect, like finding yourself in a still and calm pool on the river. But now we are moving again – there are stoats to trap and a whio population to look after, and it sure is good to be back in the flow!