Rodent Monitoring on Kotuku Peninsular: Trying to find a needle in a haystack. by Tony Bouzaid
Environmental News Issue 20 Spring 2009 

An intensive monitoring programme over a 50m x 50m grid of tracking tunnels across Kotuku Peninsula has yielded some interesting results.
Once a month a group of 8 volunteers led by Envirokiwi have installed ink cards in 906 tracking tunnels over two days then pulled them in over the next two days. The first run in September showed rat prints on one card under a house in Arthur’s Bay on the Karaka Bay side of the peninsula. The second run in October yielded no prints on any of the cards. The third run in November changed the dynamics considerably.
In Garden Bay in Port FitzRoy one card near the shore showed a rat print on the 6th, the last day of the monitoring. We believe this rat has come ashore off a boat since there were no prints anywhere in the vicinity till this time. The following day we installed rat traps, bait stations, cards and hand-spread bait in the vicinity. The following day when we checked the rat had moved along the coast bait line 250m to leave a print in the last tunnel with a card. Two days later trying to jump ahead we installed traps and baited stations from 500m ahead of the last print. A day later and no traps had been tripped or bait taken or prints on cards. A dead rat smell was noticed in the vicinity of the last card print but no evidence of the rat dead or alive!
Arthur’s Bay at the Karaka Bay end of the fence was another story. Rats were trapped consistently on the outside of the fence near the end then one was trapped along the inside of the fence. While the last monitoring run was in progress a print of what was taken for a juvenile rat was recorded in the chook run. Subsequently a kiore was trapped inside the fence near the vehicle gate and another yet to be identified by the chook run.
Ditch Keeling spent 3 weeks on the peninsula tracking for rabbits and cats with one juvenile cat caught in Ley’s Bay on the Karaka Bay side. At the end of the period he hadn’t found evidence of a single rabbit and declared the peninsula clear of cats. If there had been any remaining cats they must have gone over the fence as they can exit easily enough.
The next monitoring run will be held from the 15th to 18th December for which we are again looking for volunteers. On the last run we had 4 members of the Cradock family come on their yacht and spend 2 days in the bush with us. I am grateful for the local volunteers who gave up so much of their time for days on end to tramp round some very rugged terrain inserting and removing ink impreg-nated cards. The greatest reward is finding 905 cards without rodent prints.