Pest numbers are down and native birds are beginning to bounce back in the Tararua Forest Park north of Wellington following an aerial 1080 pest control operation in late 2010.

The operation, coordinated by DOC and Animal Health Board (AHB), aimed to restore forest health and boost native bird populations, as well as protect Wairarapa cattle and deer herds from bovine TB.

Intensive monitoring undertaken by DOC, the AHB, Landcare Research and Greater Wellington Regional Council before and after the operation has shown significant drops in pest numbers and increasing populations of some native bird species.

New Zealand parakeet/kākāriki

Although still early days, Dr James Griffiths of DOC said that signs for some bird species were promising. “Counts have shown that rifleman, whitehead and kakariki have all increased following the operation, compared to the non-treatment area where no 1080 was applied,” he says.

These species are all able to breed quickly but are also very vulnerable to predation. “In this respect they are like canaries in the coalmine and can give us an early indication if pest control is working.”

A decrease in possum and rat numbers, which have stayed at low levels for the two years following the operation, is also encouraging says Dr Griffiths. “We are making a major investment in monitoring to assess the long term results of this aerial 1080 operation on a range of predators. If we can keep predator numbers down it gives native bird populations an opportunity to breed successfully.”

Rifleman and mistletoe

“Stoat numbers are also tracking at low levels, but we haven’t detected a significant change as they were at low levels prior to the operation. If stoat numbers had been high prior to the operation we would have expected to see a significant drop now.”

The operation was part of Project Kākā, a 10 year DOC programme aimed at restoring the health of a 22,000 hectare belt of the Tararua Forest Park stretching from Otaki Forks to Holdsworth in the Wairarapa.

Whitehead/pōpokotea

“As we collect more data over the 10 year term of the project the effect of 1080 on forest birds and pest animals in the Tararua Forest Park will become clearer. We may also start to see positive changes in the bird counts for slower breeding species such as kākā.”

Rat, possum and stoat numbers will be controlled every three years in the Project Kākā zone through the aerial application of 1080, with the next operation scheduled for spring 2013.

Project Kākā aerial pest control efforts are also being supported by community volunteer trapping at Donnelly Flats. It is hoped that over time sustained pest control in the Tararua ranges will allow for rare species re-introductions such as whio, robin and kiwi.