Evaluation of Rodent Bait Station Use Under Controlled Conditions

A method was developed to evaluate the responses of groups of wild Norway rats to bait stations. Groups of rats were first acclimated to test arenas of 5.6 m2 which each contained abundant harborage in the form of a covered pallet, drain pipes, and masonry blocks. Activity levels were measured daily by four methods: bait consumption, tracks, fecal counts, and motion detector (actimeter) counts. When activity had stabilized, one bait station containing an attractive nontoxic food and additional actimeters were added to each arena. Daily observations revealed changes in activity around the exterior of stations, time until entry, and the initiation and quantity of consumption of the station bait (unpoisoned EPA meal). In tests using the protocol, replicated comparisons were made of eight “tamper-proof” bait stations having various degrees of design complexity. In general, simpler designs showed more rapid and greater utilization and bait consumption. The method has application to evaluations with house mice and for studies of toxic baits in particular station designs.