Spotting the rare whio
It’s rare, shy, elusive, endangered… and if you’re lucky, you might be able to stand on the side of State Highway One and spot it.
It’s New Zealand’s native blue duck, the whio, which lives in clear, fast-moving mountain streams and eats mayflies, stoneflies and caddis flies, using its unique lip to scrape food off rocks. With its habitat threatened by environmental pollution and its population decimated by pests, the ducks have been retreating into the back country for decades.
But a national programme to save the whio, partly based out of the Tongariro National Trout Centre, and pest-trapping to reduce the numbers of predators preying on the ducks is paying dividends in the Central Plateau. To many people’s excitement, whio have been regularly spotted on the Tongariro River just under the main road river bridge.
The news is also good on the western side of Mt Tongariro where an annual whio survey of the Whakapapa, Mangatepopo and Whanganui rivers found that the whio population has soared from 30 pairs in 1998 to 130 pairs and 252 ducklings counted last December, largely thanks to stable river flows during nesting and brood rearing and effective predator control.
Blue duck typically inhabit clean, fast-flowing streams in forested upper catchments of rivers and their biggest enemy is the stoat, which attacks females on the nest, steals eggs and takes young ducklings. They are also vulnerable to feral cats, domestic dogs and ferrets, with rats and possums also considered a threat.
Dave ‘Didymo Dave’ Cade, first spotted whio near the main road bridge on the Tongariro River a couple of years ago but says they have been showing up more regularly over recent weeks. First he saw a single one and then last week ago he spotted a pair, and says local fishermen have seen more.
He says that’s not only great for the ducks, which are classified ‘nationally vulnerable — threatened’ but great for people too, who may have the opportunity to spot these rare birds for themselves.
“I just find it incredible that people can go down there and stand on the banks and see them because they have always traditionally been back country and you couldn’t get to them.
“Even an 80 year old could walk to those places and see whio and we’ve never seen that before. I don’t know of any other locations in New Zealand you can see whio from State Highway 1.” Whio have also been spotted on the Hinemaiaia Stream near the main road bridge, Dave says.
While the whio’s success story is due to several factors and numbers have been rising over the entire central North Island over the last 14 years, whio on the Tongariro River have had a team of locals looking out for them. Tongariro River Rafting owner Garth Oakden set up the Blue Duck Project Charitable Trust nine years ago. It now has traps from Tree Trunk Gorge to the main road bridge as well as on the Whakapapa and Manganui-o-teAo rivers. When the project began there were three pairs on the Tongariro, and now there are around 30, Garth says.
“I couldn’t be prouder of what we’ve achieved but we couldn’t do it without our volunteers, they’re key to the whole thing.”
He said with the whio now moving into areas where there were also people, dogs must be kept under control near the river.
Cam Speedy, a trustee on the Central North Island Blue Duck Trust, says seeing whio on the lower Tongariro River mirrors a general region-wide expansion of whio in the area which has seen the birds finding new territories.
In one case, a bird banded on the Whakapapa River in 2007 was later found with a mate living on the headwaters of the Rangitikei River in the Kaimanawas, 64km away.
Region-wide conservation efforts, including the Blue Duck Project Charitable Trust on the Tongariro, the Conservation Department and Genesis Energy’s Whio Forever partnership, begun on the Tongariro River in 2004 and spread nationwide, conservation by local hapūr Ngāti Hikairo, the Sika Foundation Whio Initiative and work by ecologist Nick Singers on the Waimarino River headwaters, had all contributed to the population thriving, Cam said.
Conservation work and predator control is helping whio return to Central Plateau rivers.
A pair of whio under the State Highway One bridge over the Tongariro River in Tu¯rangi.