Populations of invasive wild pigs (Sus scrofa) are increasing in many regions of the world, in particular the United States and Australia. Invasive wild pigs cause extensive damage to ecological resources and agriculture. Development and registration of a safe and humane toxic bait offers a practical and cost‐effective tool to control invasive species. Currently, no toxicants are approved for use on invasive wild pigs in the United States and those approved in Australia are under scrutiny because of concerns regarding humaneness and effects on nontarget species. We tested a newly formulated bait containing the micro‐encapsulated active ingredient, sodium nitrite (HOGGONE®; Animal Control Technologies Australia P/L, Victoria, Australia), that is considered humane and safer for nontarget species because it does not bioaccumulate. We examined palatability, lethality, and stability of the bait (i.e., fresh compared to 8‐month‐old bait) on groups of captive invasive wild pigs. We found HOGGONE® was a preferred food item, averaging 475 g of toxic bait consumed per animal during the first night offered. Consumption of HOGGONE® resulted in 95% mortality (53 of 56) in the treatment groups across 2 treatment nights. Most mortalities (98%) occurred during the first night the toxic bait was offered. Camera evidence suggested that deaths occurred within 3 hr post‐offering. The toxic bait was stable and effective up to 8 months post manufacture. Our results support current applications to register HOGGONE® for reducing damage from invasive wild pigs in the United States and Australia. Further research is required to evaluate HOGGONE® on free‐ranging invasive wild pigs using bait stations that exclude nontarget species. © 2017 The Wildlife Society.

Populations of invasive wild pigs (Sus scrofa; hereafter, wild pigs) are expanding, requiring costeffective tools for control, and disease prevention, such as toxic or vaccine baits. Specifically, development of a novel and humane toxicant is underway for control of wild pigs in the United States and Australia. A speciesspecific bait station for delivering the toxic bait must be used to protect nontarget animals. Further, a bait station must be designed to maximize feeding by wild pigs by accommodating their group-feeding behaviors. We sought to develop a bait station that delivered bait to the maximum proportion of wild pigs and excluded the most ubiquitous nontarget species, specifically white-tailed deer (Odocoileus virginianus) and raccoons (Procyon lotor). We used direct observations and cameras during 2015 to evaluate wild pig feeding behavior and nontarget access for various sizes, arrangements, and construction materials of prototype bait stations in pen and field settings in Texas, USA. We found that a bait station constructed of 2 back-to-back troughs, 1.1 m in length, without a divider was sufficient for feeding the largest proportion of wild pigs in pens. Using this design of bait station at 30 field sites, we found that wild pigs fed more frequently from plastic than metal bait stations, although both bait stations reduced feeding by wild pigs compared with control sites. From near-video imagery at 3 field sites, we identified that 80% of wild pigs (33 of 41), 0% of white-tailed deer (0 of 7), and 17% of raccoons (1 of 6) accessed the bait stations on the final night of testing following a 2-week acclimation and training period. Future steps toward development of a wild pig-specific bait station include adding resistance to the lids of bait stations to completely exclude raccoons and identify baiting strategies that most efficiently acclimate wild pigs to using bait stations. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.

Range expansion of feral swine (Sus scrofa) continues to be pervasive in the United States.

BackgroundIn 2018, a sodium nitrite (SN)‐based toxic bait for invasive wild pigs (hereafter wild pigs; Sus scrofa), was evaluated to determine its effectiveness in reducing local wild pig populations in Texas. Localized population reductions of >70% were achieved, but spillage of bait outside wild pig‐specific feeders (bait stations) caused by feeding wild pigs resulted in the deaths of non‐target animals. To evaluate risks to non‐target animals, we tested whether bait presentation influenced the total amount of bait spilled by wild pigs and estimated the associated risk to non‐target species.ResultsWe found that bait spilled outside bait stations could be reduced by >90% when compacted in trays, as opposed to being manually crumbled into pieces. We documented a mean spill rate of 0.913 g of bait per wild pig. Conservative risk assessments for nine non‐target species for which SN toxicity data exist indicate that there is relatively low risk of lethal exposure, apart from zebra finches (Taeniopygia guttata) and white mice. Our results indicate that there may be enough spilled bait per feeding wild pig to kill 9.5 or 3.5 individuals of these species, respectively. Other species assessed range from 0.002 to 0.406 potential mortalities per wild pig.ConclusionWe demonstrated that the amount of bait spilled by wild pigs during feeding and the associated risk to non‐target animals can be minimized by presenting the bait compacted in trays within bait stations. We recommend that baits be tightly compacted and secured in bait stations to minimize risks to non‐target animals from spilled bait by wild pigs. © 2023 Society of Chemical Industry. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.