Invasive feral swine (Sus scrofa) cause extensive damage to agricultural and wildlife resources throughout the United States. Development of sodium nitrite as a new, orally delivered toxicant is underway to provide an additional tool to curtail growth and expansion of feral swine populations. A micro-encapsulation coating around sodium nitrite is used to minimize detection by feral swine and maximize stability for the reactive molecule. To maximize uptake of this toxicant by feral swine, development a bait matrix is needed to 1) protect the micro-encapsulation coating so that sodium nitrite remains undetectable to feral swine, 2) achieve a high degree of acceptance by feral swine, and 3) be minimally appealing to non-target species. With these purposes, a field evaluation at 88 sites in south-central Texas was conducted using remote cameras to evaluate preferences by feral swine for several oil-based bait matrices including uncolored peanut paste, black-colored peanut paste, and peanut-based slurry mixed onto whole-kernel corn. These placebo baits were compared to a reference food, whole-kernel corn, known to be readily taken by feral swine (i.e., control). The amount of bait consumed by feral swine was also estimated using remote cameras and grid boards at 5 additional sites. On initial exposure, feral swine showed reduced visitations to the uncolored peanut paste and peanut slurry treatments. This reduced visitation subsided by the end of the treatment period, suggesting that feral swine needed time to accept these bait types. The black-colored peanut paste was visited equally to the control throughout the study, and enough of this matrix was consumed to deliver lethal doses of micro-encapsulated sodium nitrite to most feral swine during 1–2 feeding events. None of the treatment matrices reduced visitations by nontarget species, but feral swine dominated visitations for all matrices. It was concluded that black-colored peanut paste achieved satisfactory preference and consumption by feral swine, and no discernable preference by non-target species, compared to the other treatments.

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. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

Disease and damage from white-tailed deer (Odocoileus virginianus) continually threaten the livelihood of agricultural producers and the economy in the United States, as well as challenge state and federal wildlife managers. Threats can be partially addressed by excluding free-ranging deer from livestock-related resources. Throughout the year, use of stored livestock feed by deer in northern Lower Michigan (MI), USA fluctuates, though their presence is relatively consistent. Since 2008, use of livestock areas and resources by deer has been reduced through intensive efforts by livestock producers in cooperation with state and federal agencies. These efforts focused on excluding deer from stored cattle feed in areas where deer were abundant. We monitored deer activity from Jan 2012 to June 2013 on 6 cattle farms in northern MI using GPS collars to evaluate behavioral effects of excluding deer from stored feed. We characterized areas deer occupied before and after installing 2361 m of fences and gates to exclude deer from stored cattle feed. Following fence installation, 9 deer previously accessing stored feed shifted to patterns of habitat use similar to 5 deer that did not use stored feed. However, continued attempts to regain access to stored feed were made at low frequencies, emphasizing the need to maintain the integrity of fences and keep gates closed for damage prevention and biosecurity.