Monitoring is showing encouraging early results for the Zero Invasive Predators Ltd (ZIP) and Department of Conservation (DOC) trial in a 2,500 ha forest block near Jackson/Arawhata in South Westland.

The trial is part of our work to develop a method to completely remove possums, and potentially rats, from mainland sites. If successful, this method of predator removal will reduce, and ultimately eliminate, the need for repeated wide scale aerial application of toxins to control predators; and provide a tool for progressing New Zealand towards its Predator Free 2050 goal.

Phase One

Phase One of the trial involved two aerial applications of non-toxic cereal ‘pre-feed’ bait in June, followed by a single application of 1080 cereal bait on 5 July 2017, to attempt to reduce predator numbers to ‘functional extinction’ (i.e. the population is no longer viable).

Intensive monitoring in a 400 ha core of the trial block is currently being undertaken with promising early results.  A team of five people are regularly checking 800 monitoring points in the block. This monitoring will continue for approximately 50 days to ensure an accurate assessment of survivorship (if any), and provide confidence around the effectiveness of the method. As at 31 July 2017, no evidence of rat or possum survival has been found.

If no surviving possums or rats are detected after 50 days, then the trial will be complete.

Phase Two

If monitoring does find survivors a second phase will consist of two further pre-feed applications of non-toxic bait and a second 1080 application. The aerial pre-feed applications of non-toxic bait will begin within the initial Phase One 50-day monitoring period, in order to ensure that the Phase Two 1080 operation, if required, happens as close to the 50-day window as possible to avoid any successful breeding by survivors.

The two phases use different cereal baits with different ‘flavoured’ lures to reduce the chance that target individuals learn to avoid the bait after trying it during the first phase. Both 1080 operations will use the same strength toxin.

For more information, please refer to our Fact Sheet on the trial.