Date of this Version
Wildlife Society Bulletin 41(2):264–270; 2017; DOI: 10.1002/wsb.756
With the development of a toxic bait (HOGGONE®) for the control of invasive wild pig (IWP; Sus scrofa) populations in the United States, there is a need to develop a bait station to mitigate potential effects on nontarget species. Our objective was to identify characteristics of a bait station that can successfully exclude raccoons (Procyon lotor)—a ubiquitous and dexterous nontarget species—while facilitating bait consumption by IWPs that exhibit group-feeding behaviors. We evaluated abilities of captive raccoons (n = 19) and IWPs (n = 41) to open the lids of prototype resistance assessment bait stations (RABS) under various levels of resistance (range = 1.1–18.1 kg) at research facilities in Colorado and Texas, USA, during July–August 2014. We found that similar proportions (0.65) of individual raccoons and IWPs in our tests opened lids with 0–1.4 kg resistance, which decreased as resistance increased. No raccoons opened lids with ≥13.6 kg of resistance. However, equal proportions (0.45) of IWPs opened lids with 13.6 kg and 18.1 kg, and a greater proportion (0.73) secondarily accessed RABS after other IWPs opened them. Scrounging behaviors of IWPs (i.e., aggressively taking access to food from less dominate IWPs) increased as the levels of resistance increased, but similar proportions of animals gained access. These results suggest that a threshold-weight-of-resistance of 13.6–18.1 kg on hinged lids excludes raccoons and allows access by IWPs. Furthermore, bait stations designed to allow multiple IWPs to feed simultaneously may be preferred because of group feeding behaviors. Field evaluations are required to evaluate the exclusion of other nontarget species (e.g., white-tailed deer [Odocoileus virginianus], black bears [Ursus americanus], and coyotes [Canis latrans]), potential scrounging behaviors by nontargets, and bait consumption by IWPs.