DOC/Supplied
The whio population in Kahurangi National Park has had an increase of 340% since 2000.
A Department of Conservation (DOC) survey into the whio population in Kahurangi National Park has seen a massive increase and DOC are saying it is thanks to the combined efforts of the community, businesses and a captive breeding facility.
The survey, which started in 2020 and is ongoing, has to date found an increase of 340% in whio (blue duck) numbers since 1998-2000 when DOC last surveyed the bird.
Currently, there are 846 adult whio in Kahurangi with 335 breeding pairs among them.
This is an increase from the 2000s survey which recorded only 191 whio and 58 breeding pairs in the park.
DOC science technician Jason Malhan said the “combined endeavours” of DOC, the community, businesses and a captive breeding facility have “greatly improved the fortunes of whio” in the park.
After the last survey, DOC started two security sites in the early 2000s to protect whio with stout trapping and boosting breeding techniques to fast-track population growth.
“The Ōpārara-Ugly and Wangapeka-Fyfe Whio Security sites have both surpassed the goal of 50 breeding pairs,” Malham said.
Support from businesses like Genesis, through their Whio Forever programme, the Issac Conservation and Wildlife Trust in raising whio ducklings, as well as contractor and community help in maintaining traps, has been “instrumental” in increasing numbers.
DOC/Supplied
DOC staff have walked 700km of the waterways in Kahurangi so far and have been “encouraged” by the whio increases.
Other volunteers include Tapawera Area School students and community groups Friends of Flora, the Friends of Cobb and the Mokihinui-Lyell Trust.
These volunteers help to lay traps in catchment areas like Cobb Valley, the Flora Stream catchment and Old Ghost Road.
There was also an Air New Zealand supported biodiversity project in Gouland Downs setting up a trapping network to protect whio, takahē, roro/greatspotted kiwi and other native species, Malham said.
Currently, whio pairings have been found mostly around security site rivers where stoat trapping is supplemented with aerial 1080 predator control, Malham said.
“The average pair density on rivers with both forms of predator control was 0.76 pairs per kilometre with 1080 alone and 0.12 pairs per kilometre before predator control.”
2023 was a tough year for the whio as the number of breeding pairs measured nationally dropped by 15% to 587. The decrease is linked to flood damage which made it difficult for traps to be reset. Video supplied by Genesis Energy.
The increase hasn’t come without its downfalls, with climate change and repeated flooding impacting breeding spaces, and a “mega breech mast” in 2019 which saw a number of rodents, stoats and feral cats invade the area.
Aerial 1080 predator control was carried out over a large part of the park during this time, but it wasn’t possible to cover all the park.
Currently, DOC staff have walked over 700km of the waterways in Kahurangi and while exact numbers of whio aren’t possible, staff are “highly encouraged” by the increase they have seen so far.
