Predator control sees whio thrive

Date:  16 May 2019

This is the best result for the whio here since intensive trapping work started on 20 km of the Oparara River in 2002. At that time there were four pairs of whio, and juvenile survival was low, meaning the population was aging with very few new breeding pairs.

The Oparara Ugly site has grown considerably, and whio are now protected across 92 km of the Oparara, Ugly, Kākāpō, Huia and Little Wanganui Rivers.

DOC, with the support of Genesis through the Whio Forever Programme maintains nearly 1,500 trap boxes on the river margins, which are cleared monthly. This work helps to keep predator numbers to a minimum between 1080 pest control operations giving vulnerable whio the best chance of surviving the nesting season. Whio eggs, ducklings and nesting female ducks are at risk of predation by stoats, which are a major cause of their decline across New Zealand.

Genesis Environmental Coordinator Cam Speedy who works with the DOC whio technical team, says the results are incredibly gratifying.

“These sorts of numbers make the hard work done by so many people all worthwhile. Seeing the partnership support communities working to restore the whio in the wild is immensely satisfying.”

The trapping and pest control work takes place alongside intensive captive breeding work to help build the population. This work is supported by The Isaac Conservation and Wildlife Trust who assist DOC by hatching eggs and raising ducklings which are then returned to the river as young adult birds. This results in increased numbers of breeding pairs which in turn helps to foster a self-sustaining population at the site.

Buller DOC Operations Manager Robert Dickson says the good results mean that people will be increasingly likely to encounter whio on their adventures in the Oparara Area, “As well as good results for the whio, the extra pest control in the Oparara and Ugly catchments will be providing benefits to an array of forest species”.

Genesis and DOC have partnered in a five year programme to secure the future of this threatened native bird. The Whio Forever partnership is implementing a national recovery plan to protect whio breeding areas and habitat.

More about whio

The whio is a threatened species of native duck only found in New Zealand’s fast flowing waters. Featured on New Zealand’s $10 note and with an estimated population of less than 3,000 birds, whio are rarer than kiwi.

Whio are adapted to live on fast-flowing rivers. Finding whio means you will also find fresh, fast-flowing water with a good supply of plants and underwater insects. This makes whio important indicators of ecosystem health – they only exist where there is quality fresh water and an abundance of life.

Conservation issue

The whio are predated by stoats, ferrets and cats with the largest impact during nesting time when eggs, young and females are vulnerable, and also when females are in moult and can’t fly. Extensive trapping can manage these predators and work in key whio habitats by DOC and Genesis on the Whio Forever Project has already seen an increase in whio numbers.

Whio cannot be moved to predator-free islands like other species because of their reliance on fast-flowing rivers. Pairs occupy approximately 1 km of water – so they need a lot of river to sustain a large population and they fiercely defend their territories, which makes it difficult to put them with other ducks in captivity.

They are susceptible to flood events which, destroy nests, fragment broods and wash away their valued food source.

Whio Forever

Genesis has a strong historic association with whio through the Tongariro Power Scheme. In 2010 this association grew through the establishment of Whio Awareness Month (March). Today, Genesis and DOC continue their partnership through The Whio Forever Project, which aims to secure the future of whio in the wild and ensure New Zealanders understand and value whio in our rivers. The support of Genesis and the work of DOC has enabled the Whio Recovery Plan to be implemented.

Contact