Rodenticide Trial for 'No-Rats' on GBI

Environmental News Issue 9

THE NEW RODENTICIDE ‘No-Rats’ is to be trialed soon in the Rosalie Bay Catchment on Great Barrier. As part of researching options for the eradication of rats on Great Barrier Island, John Ogden and Judy Gilbert recently met with the director and head scientist of the distributing company KiwiCare. No-Rats is a cellulose based product that rats are unable to digest as they do not have the required bacteria in their gut. The particular cellulose used at high concentrations causes the rats to become constipated and die quite rapidly from heart failure. The product literature claims the bait is rat specific and lethal after a minimum of 40grams has been ingested. The non toxic product has been trialed overseas on a number of other bird and animal species, including dogs, ducks, cats, and cattle, and while some had temporary constipation, none sickened or died. No-Rats is certificated for use on rats in New Zealand and has Bio-Gro status.

While No-Rats has performed well in controlled conditions overseas, there have not been any field trials in NZ. With good track infrastructure and an established record in product trials, the Windy Hill Rosalie Bay Trust is well positioned to be able to undertake the trial of this product. If it trials successfully No-Rats could be a very positive way of managing rats on the Barrier without toxins. KiwiCare is keen to have their product trialed in the field here and has agreed to supply the Windy Hill Rosalie Bay Catchment Trust with enough bait to cover a 30-40 hectare area over 6-8 weeks starting in the autumn. Two areas have been selected – one has rats already managed at low densities and covers open fields with multiple buildings while the other area has not had any pest management, has rats at high densities, and covers regenerating Manuka and mature forest. Two areas allows for the product to be trialed in different habitats with varying rat densities. A control area was established last year and will also be used as a measure of management efficacy.