Proceedings of the Vertebrate Pest Conference

Roof rats (Rattus rattus) are invasive commensal rodents that pose a significant threat to both natural and manmade environments. Like other commensal rodents, roof rats are often controlled with rodenticides placed within bait stations, but rats can be slow to visit stations or avoid them altogether. We tested whether the addition of a scent lure (Airzonix; VM Products) would increase visitation and use of bait stations in 36 residential yards in Orange County, California. We placed two EZ-Secured (VM Products) stations, one containing a scent lure and non-toxic bait (treatment) and one containing bait only (control), in each yard, and monitored them continuously with digital game cameras for three weeks. We compared time to discovery and entry, bait consumption, and nightly roof rat activity between scent lure and control stations. The addition of a scent lure did not reduce time to discovery or entry significantly, nor did it increase bait consumption or rat activity, although rat behavior differed around scent lure and control bait stations. Overall, although roof rats discovered bait stations fairly quickly (median time to discovery 124-195 h), they entered and consumed bait in only a fraction (50-60%) of the stations, and were slow to enter stations (median time to entry 318-387 h), underscoring that additional techniques are still needed to improve the attractiveness and efficacy of bait stations.