New Zealand Journal of Ecology (2023) 47(1): 3517

Developing a new resetting tool for controlling rats

Research Article
Elaine C. Murphy 1,2*
Tom Agnew 1,3
Tim Sjoberg 1,4
Charles T. Eason 1
Duncan MacMorran 5
James G. Ross 1
  1. Department of Pest Management and Conservation, PO Box 85084, Lincoln University, Lincoln 7647, New Zealand
  2. Department of Conservation, Private Bag 4715, Christchurch 8140, New Zealand
  3. Zero Invasive Predators, Lincoln University, Lincoln 7647, New Zealand
  4. Pest Free Banks Peninsula, 698 Christchurch Akaroa Road, Halswell, Tai Tapu 7672, New Zealand
  5. Connovation Ltd, PO Box 58613, Botany, Auckland 2163, New Zealand
*  Corresponding author

A resetting toxin device (the “Spitfire”) has been designed that delivers a toxic paste to a rat’s ventral surface when it passes through a tunnel. The rat grooms off the paste and ingests the toxin. The system was assessed in cage trials and one field trial. The purpose of the cage trials was to investigate whether a range of toxins can be delivered by the Spitfire to rats (Rattus rattus and R. norvegicus), namely 0.55% sodium fluoroacetate (1080), 0.2% brodifacoum, 15% cholecalciferol, and 12.5% zinc phosphide. The trials with 1080, brodifacoum, and zinc phosphide were successful with > 85% of rats ingesting lethal doses. The trials with cholecalciferol were less successful with only 58% of rats dying. A one-month pilot field trial was undertaken using 1080 in the Spitfires. There was a knockdown in rat (and stoat Mustela erminea) abundance, establishing proof of concept for the Spitfire delivery system with this toxin. The long-term, effective control of introduced rats will require a range of toxins with different modes of action. The Spitfire could be a useful additional control tool for rats and is currently being re-engineered to be made more reliable.