Countdown to Eradication
by Tony Bouzaid


Planning is well advanced for the eradication of pests from Kotuku Peninsula. The first stage has been preparing the ground for the aerial bait drops as was carried out on Kaikoura Island in August last year.

The first pest to be eliminated was the pig which was carried out by John Bacon after the fence was finished and the vehicular gates closed. It took several visits before we could finally say the last one was dealt with.

The remaining pests we have left to eliminate are rats, mice, rabbits and cats. In order to trace any rats or mice that survive the bait drop we have installed a 50m x 50m grid of tracking tunnels across the entire peninsula. This involved establishing GPS coordinates for all the existing bait lines then planning new lines where there was more than a 50m separation. Envirokiwi were employed to cut and mark lines through the bush, then measured out at 50m intervals along the lines where tracking tunnels were pegged to the ground and identified with a code. Tracking tunnels will also be positioned in between all the 543 bait stations.

Another job is preparing the dwellings for the drops which where possible means rabbit proofing the buildings with wire mesh so that there is less places to hide or burrow. We will be hand spreading bait around and under the buildings with bait stations inside at selected locations as well.

One of the most difficult jobs is spraying all the rank kikuyu to get it matted down before the drops as the bait will not penetrate to the bottom where mice and rats will often live. As there is a considerable amount of this outside the fenced paddocks it has to be sprayed twice for a thorough kill. It will then require some heavy rain to mat down.

After the second bait drop we will monitor the tracking tunnels in order to locate surviving rodents. We estimate it will require 10 people for 6 day stints, 3 days to put cards in all the tunnels and another 3 days to bring them all in. This will have to be done once a month for 6 months and if after that time no sign is found then every 3 months for 2 years. We are keen to hear from anyone who is keen to volunteer for this duty which will occur between September 2009 and March 2010 initially. Once we can satisfy the powers that be (viz the Department of Conservation) that we have successfully eradicated the rats and cats we will apply for the reintroduction of other endangered species that were once resident on the island.

Buffer zone controls are being set up around the fence ends, along the shorelines and around the dwellings to monitor rodent activity before the drops and after to check for any incursions. These consist of bait stations, rat traps and tracking tunnels. Signage will be installed around the peninsula beforehand to warn people about the bait drops and after to advise them of the pest free status of the peninsula and to check their boats for rodents before anchoring.

Over the last week I have become aware of three recent occasions where boats anchored in Kiwiriki Bay and Kaiaraara Bay have been boarded by rats at night. This is a clear indication that the rat density in these areas is extremely high, particularly now when the trees are fruiting and there is plenty of food about.