An independent review of the Pukaha Mount Bruce forest restoration project has both confirmed the overall direction of the project and recommended several areas for boosting pest control efforts in the 942-hectare reserve.
The independent review, carried out by Lincoln University ecologist Dr James Ross, was commissioned in June, prior to the ferret attacks which killed 12 kiwi in August.
Forest Restoration and Predator Control Programmes – DOC Update February 2011
The Department of Conservation is contracted by Pukaha Mount Bruce Board to undertake forest restoration and predator control work at Pukaha Mount Bruce.
DOC has provided an update to the Board on these activities over the last few months and their report is set out below. It begins:
Following the kiwi predation events of May 2010, we have modified our mustelid trapping programme considerably. Most Fenn traps within the forest have been replaced with DOC200 traps and perimeter traps have been replaced with DOC 250 traps. Traps at track entrances to the forest have been reinforced with additional DOC 250’s. These modifications were designed to improve our mustelid catch and in doing so, improve protection for kiwi. The DOC 250s have proven particularly successful in catching stoats and ferrets. A total of 7 ferrets and 10 stoats have been destroyed since September 2010. It is our intention to further strengthen this successful line of defence.
Due to the ongoing support of our community and sponsor agencies the Pukaha Restoration Project continues to be successful in restoring the forest to its former glorious state.
Early in 2010 we discovered kaka were accessing bait stations in the forest containing Pestoff 50D baits, targeting rats. We immediately began kaka-proofing the 1200 bait stations within the forest. However, later in the year we found six dead adult kaka in the forest. Pathology and toxicology examinations indicate poisoning was a possible cause of death for three of the birds. No further losses have been recorded. We have advised our regional council project partners that kaka have been accessing bait stations, and the Department of Conservation’s national office has been briefed on this, and the results of toxicology testing.
For reasons about which we are uncertain, we have been unsuccessful in reaching our target rat population this season. Potentially this is due to the modifications we have made to bait stations in order to prevent kaka accessing the rat bait or maybe it is a result of some other unknown factor. We are aware that rat control projects elsewhere in New Zealand have experienced similar difficulties this year including those where bait stations have not been modified.
The impact of the high rat population is that the current season’s kokako fledging will be threatened and we potentially may experience a lower than expected kokako recruitment at Pukaha this year. Adult birds should not be threatened as a result of high rat numbers.
Recent events have highlighted the challenges of forest restoration, and our reliance on intense and sustained pest control to keep our native wildlife safe. But we remain confident of the success of the Pukaha project. The kaka population in the forest has swelled to around 100 since the reintroduction of nine birds in 1996, and reintroduced kokako and kiwi are breeding. It’s enabling people to get a sense of how New Zealand used to be, when this forest remnant was part of the majestic 70 mile bush that was alive with native birdsong.