Duckling boom delights Whirinaki visitors

Date:  15 June 2018

The track to Central Whirinaki Hut runs right through the middle of an intensive trap network that was bolstered by a Battle For Our Birds aerial 1080 treatment to knock down rats and stoats during 2017.

Blue duck/whio are rarer than kiwi, but numbers are now booming in the Whirinaki Security Site, one of eight locations across New Zealand where Genesis is helping the DOC protect and enhance the bird’s population through the Whio Forever project.

The latest monitoring of whio pairs in the wider Whirinaki following the 2017 operation showed 12 pairs produced 32 ducklings between them with 25 reaching adulthood. This is a 60% increase in ducklings produced and a 66% increase in those ducklings fledging from the previous year, when just trapping was used to protect the birds.  

The success of the protection programme means the population of whio along a 17 km stretch of the Whirinaki River has gone from 16 pairs before trapping started in 2011 to 33 pairs in 2016. 

DOC Ranger Jacob De Vries said this abundance makes the track to Whirinaki’s Central Whirinaki Hut a mecca for whio admirers.

“There are so many in there now, that walking up the track it’s pretty rare not to see one. More often than not they see you first and you can hear them whistling to their mates to tell them they have a visitor.”

When planning a trip to the park, check out www.doc.govt.nz/whirinaki for more info.

Background information

Blue duck/whio are endemic to New Zealand – they depend on fast flowing clean rivers surrounded by native vegetation to survive. However, because of issues like habitat loss and vulnerability to introduced predators, whio are a threatened species. 

Surveys in the Whirinaki Forest indicated, that although habitat loss was not an issue, whio were not flourishing, their ducklings were not reaching adulthood, and streams that could hold many more whio were often nearly empty. 

Nationwide monitoring showed that stoats were the number one cause of the decline, with a shocking 90% of whio nests lost and 46% of females lost while sitting on the nests outside managed areas in Aotearoa. 

Across the country, Genesis is partnering with DOC in a five-year programme to support whio recovery and build self-sustaining whio populations. Operating under the name of Whio Forever this partnership is implementing a national recovery plan to protect whio breeding areas and habitat. 

Genesis and DOC have focused on eight ‘Security Sites’ in Aotearoa to build self-sustaining whio populations – the Whirinaki Forest is one of the most important of these sites. 

The Whirinaki whio Security Site trapping networks currently covers over 3800 ha and approximately 60 km of waterways. The site was also treated with aerial 1080 during 2017 as part of a larger operation to knock down numbers of stoats and rats across the 38,000 hectares of the wider park.

• The whio is a threatened species of native duck that is only found in New Zealand’s fast flowing waters. Featured on New Zealand’s $10 note and with an estimated nationwide population of less than 3000 birds, whio are rarer than kiwi.
• Whio are adapted to live on fast-flowing rivers so 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.

The support of Genesis is enabling DOC to double the number of fully secure whio breeding sites throughout the country, boost pest control efforts and enhance productivity and survival for these rare native ducks.  

Contact