Fri, Nov 17, 2023 5:00 AM
Big increase in whio numbers in Kahurangi
Whio with ducklings. Photo: DOC. Photo: Supplied
Staff Reporter
A Department of Conservation (DOC) survey shows a big increase in whio numbers in Kahurangi National Park over the past 23 years thanks to predator control and management measures to grow the native blue duck’s numbers.
The current survey, started in 2020 and still underway, has found to date a 340% increase in whio/blue duck numbers in Kahurangi since a DOC whio survey in 1998-2000. In the latest survey, 846 adult whio, with 335 breeding pairs among them, have been observed.
In the 1998-2000 survey, 191 adults whio, including 58 pairs, were counted. DOC Science Technician Jason Malham says the combined endeavours of DOC, the community, business, and a captive breeding facility have greatly improved the fortunes of whio in Kahurangi National Park since the 2000 survey.
“We started two DOC whio security sites in the early 2000s to protect whio with stoat trapping and boosting breeding with techniques that have enabled more rapid growth in their numbers. The Ōpārara-Ugly and Wangapeka-Fyfe Whio Security Sites have both surpassed the goal of 50 breeding pairs.
“Support from Genesis through the Whio Forever programme, The Isaac Conservation and Wildlife Trust in raising whio ducklings, and contractor and community volunteer help in maintaining traps have been instrumental to the security sites protecting whio and increasing their numbers.
The community volunteers include Tapawera Area School students and other locals. “Aerial 1080 predator control over large areas of Kahurangi National
Park has also increased protection for whio and other vulnerable native wildlife from high rat and stoat numbers in years when there has been beech seeding, known as a mast.
“More whio pairs generally have been found on security site rivers where stoat trapping is supplemented with aerial 1080 predator control. The average pair density on rivers with both forms of predator control was 0.76 pairs per kilometre
compared to 0.58 pairs per kilometre with 1080 alone and 0.12 pairs per kilometre before predator control or any whio management was carried out.
“Community groups are undertaking trapping which contributes to protecting whio. These include the Friends of Flora, operating in the Flora Stream catchment, the Friends of Cobb, in the Cobb Valley, and the Mokihinui-Lyell Backcountry Trust on the Old Ghost Road.
“An Air New Zealand-supported biodiversity project in Gouland Downs has a trapping network to protect whio, takahē, roroa/great spotted kiwi, and other native species.” DOC staff have walked more than 700 kilometres of waterway in the current whio survey. Exact counts of whio in the 516,000-hectare national park aren’t possible, but DOC staff are highly encouraged by the substantial increase in the Kahurangi whio population indicated by the numbers being observed.
The current survey, started in 2020 and still underway, has found to date a 340% increase in whio/blue duck numbers in Kahurangi since a DOC whio survey in 1998-2000. In the latest survey, 846 adult whio, with 335 breeding pairs among them, have been observed.
In the 1998-2000 survey, 191 adults whio, including 58 pairs, were counted. DOC Science Technician Jason Malham says the combined endeavours of DOC, the community, business, and a captive breeding facility have greatly improved the fortunes of whio in Kahurangi National Park since the 2000 survey.
“We started two DOC whio security sites in the early 2000s to protect whio with stoat trapping and boosting breeding with techniques that have enabled more rapid growth in their numbers. The Ōpārara-Ugly and Wangapeka-Fyfe Whio Security Sites have both surpassed the goal of 50 breeding pairs.
“Support from Genesis through the Whio Forever programme, The Isaac Conservation and Wildlife Trust in raising whio ducklings, and contractor and community volunteer help in maintaining traps have been instrumental to the security sites protecting whio and increasing their numbers.
The community volunteers include Tapawera Area School students and other locals. “Aerial 1080 predator control over large areas of Kahurangi National
Park has also increased protection for whio and other vulnerable native wildlife from high rat and stoat numbers in years when there has been beech seeding, known as a mast.
“More whio pairs generally have been found on security site rivers where stoat trapping is supplemented with aerial 1080 predator control. The average pair density on rivers with both forms of predator control was 0.76 pairs per kilometre
compared to 0.58 pairs per kilometre with 1080 alone and 0.12 pairs per kilometre before predator control or any whio management was carried out.
“Community groups are undertaking trapping which contributes to protecting whio. These include the Friends of Flora, operating in the Flora Stream catchment, the Friends of Cobb, in the Cobb Valley, and the Mokihinui-Lyell Backcountry Trust on the Old Ghost Road.
“An Air New Zealand-supported biodiversity project in Gouland Downs has a trapping network to protect whio, takahē, roroa/great spotted kiwi, and other native species.” DOC staff have walked more than 700 kilometres of waterway in the current whio survey. Exact counts of whio in the 516,000-hectare national park aren’t possible, but DOC staff are highly encouraged by the substantial increase in the Kahurangi whio population indicated by the numbers being observed.
