Proceedings of the Vertebrate Pest Conference

Beginning in 2009, the Army’s Natural Resource Program on O’ahu implemented the first of three ecosystem-scale rat trapping grids of traditional snap traps in the Waianae Mountains using the model outlined in The New Zealand Department of Conservation’s current best practices for kill-trapping rats. Traps were generally checked every two weeks, but bait often remained palatable for just a few nights due to slug interference. Because of the amount of labor required for single set traps, trials with Goodnature A24 self-resetting traps were conducted from 2014-2016. Early findings showed that traps were malfunctioning at a rate of ~25% and there were major deficiencies with the bait and bait-delivery system. In 2016 the bait system was improved when Goodnature developed the automatic lure pump that continually releases fresh bait for ~4-6 months. Other improvements were also made to the A24 trap to decrease the malfunction rate. In 2017, we replaced more than 1,300 snap traps at all ecosystem-scale grids with 1,000 A24s. Tracking tunnels were used as an independent monitoring system to determine rat control effectiveness. At all sites, rat activity measured in the tracking tunnels has been low (less than 15%) for over 18 months. In this paper we discuss the results of the transition from single- to multi-set rat traps, highlights some successes and obstacles, and describes grid spacing and applicability to other sites.