One of the main aims of the Centre for Wildlife Management and Conservation (CWMC) is to provide new, effective and humane tools and techniques for reducing populations of invasive mammal species. As part of this objective we have been researching innovative methods to control stoats over large areas for extended timeframes. Stoats are considered the most deadly predator of a number of New Zealand’s threatened and endangered native bird species, and have been a significant factor in the historic decline of much of New Zealand’s fauna. The majority of stoat control is presently achieved through single kill traps placed in DOC 200 boxes which must be set and serviced at regular intervals. These techniques require intensive efforts and high costs to achieve effective results. As such, there is an urgent need to develop more cost effective and sustainable stoat control tools.
In collaboration with Connovation Ltd the CWMC team has developed the ‘sptifire’, a resettable toxin delivery tunnel for the long-term control of stoats. These tunnel systems release a gel (containing a humane toxin called PAPP) onto the fur of the stoat as it passes through, which the stoat then grooms off, ingests and dies. The tunnel resets itself ready for the next stoat to enter, with each tunnel capable of killing approximately 100 stoats. These tunnels were shown in initial trials to be a quick, humane, efficient and safe method of eliminating stoats and weasels.
In January 2011 we began our first field trial of these tunnels at a Department of Conservation site in West Otago. 40 tunnels were placed in areas of high stoat densities and animal interactions with tunnels were observed by camera traps. While this trial is still on-going initial results have already shown that wild stoats will readily enter the tunnels and are successfully sprayed by the PAPP toxin. We are now hoping to achieve a significant decline in stoat numbers in this area, whilst ensuring that our tunnels can be left functioning for long periods of time unattended. Fine tuning of these tunnel systems continues with input from our design and engineering team (including experts from Lincoln Ventures Ltd and Auckland University of Technology).
Ultimately we hope to develop a cost-effective and reliable system which can be left out in the environment for several years while continuing to successfully eliminate stoats. This tunnel system will provide an important new tool in the on going battle against stoats, helping to eradicate one of the most prolific predators of native birds in this country and giving them a chance to make a recovery.
By Dr Helen Blackie