Kokako flourishing in forest

A 20-year war waged against rats and possums has seen a Waikato population of kokako reach a new milestone in genetic strength.

A survey of North Island kokako in the northern Pureora Forest east of Te Kuiti found more than 500 individual birds. It is the first kokako population considered by Department of Conservation staff as genetically robust

Kokako specialist Tertia Thurley said the latest head count marks a significant period.

‘‘We can start to safely harvest birds from there to establish new populations without impacting on our Pureora population,’’ Thurley said.

For two decades, volunteers have culled predator numbers in the Mangatutu, Tunawaea and Okahukura valleys of the Rangitoto Range.

Volunteer group, Pirongia Te Aroaro o Kahu Restoration Society, received funding in 2015 to protect a remnant kokako flock at Okahukura which allowed the separate bird populations to merge.

‘‘They started pest control in Okahukura last year and that provided a really important link between Mangatutu and Tunawaea,’’ Thurley said.

Connecting the Waipapa Valley on the eastern side of the range near Mangakino is the next target.

Keeping the predator numbers down gives the kokako a chance of successful breeding seasons said Okahukura project co-ordinator Jeanie Allport.

It prevents a ‘‘genetic bottleneck’’ leading to greater genetic diversity and reduced chance of genetic disease.

Pirongia Society volunteers have been targeting rats with pindone bait, laid at bait stations in the Okahukura valley. ‘‘In 2013, there were 22 pairs of kokako and in a recent survey, that has more than doubled. We’re giving those birds a real chance to come back,’’ she said.