Context Management of overabundant or invasive species is a constant challenge because resources for management are always limited and relationships between management costs, population density and damage costs are complex and difficult to predict. Metrics of management success are often based on simple measures, such as counts, which may not be indicative of impacts on damage reduction or cost-effectiveness under different management plans. Aims The aims of this study were to evaluate the effectiveness of aerial gunning for the management of wild pigs (Sus scrofa), and to evaluate how cost-effectiveness would vary under different relationships between levels of damage and densities of wild pigs. Methods Repeated reduction events were conducted by aerial gunning on three consecutive days at three study sites. Using a removal model, the proportion of the population removed by each flight was estimated and population modelling was used to show the time it would take for a population to recover. Three possible damage–density relationships were then used to show the level of damage reduction (metric of success) from different management intensities and levels of population recovery, and these relationships were expressed in terms of total costs (including both damage and management costs). Key results Populations were typically reduced by ~31% for the first flight, ~56% after two flights and ~67% after three flights. When the damage relationship suggests high damage even at low densities, the impact of one, two or three flights would represent a reduction in damage of 2%, 19% and 60% respectively after 1 year. Different damage relationships may show considerable damage reduction after only one flight. Removal rates varied by habitat (0.05 per hour in open habitats compared with 0.03 in shrubby habitats) and gunning team (0.03 versus 0.05). Conclusions Monitoring the efficacy of management provides critical guidance and justification for control activities. The efficacy of different management strategies is dependent on the damage–density relationship and needs further study for effective evaluation of damage reduction efforts. Implications It is critically important to concurrently monitor density and damage impacts to justify resource needs and facilitate planning to achieve a desired damage reduction goal.

There are no registered toxins available for use on Feral Swine (Sus scrofa, Linnaeus) in the United States. HOGGONE Ò is a proprietary bait matrix under development in Australia that delivers toxic levels of sodium nitrite to feral swine. However, one challenge is to develop a species-specific oral delivery system to deliver toxins to feral swine in the USA while minimizing non-target wildlife exposure. The HOGHOPPER TM is a lightweight and portable bait delivery system that could overcome this problem. Our objective was to compare non-toxic HOGGONE removal by wildlife that visited HOGHOPPERS during acclimation periods (doors open; free-feeding stage) and activation periods (doors closed; simulated toxic stage) at sites throughout the United States. We conducted 38 HOGHOPPER trials on private and public land in Alabama, Florida, Oklahoma, and Texas, and determined species-specific visitation and HOGGONE removal rates using motion-sensing digital camera systems. We found activated HOGHOPPERS to successfully exclude all wildlife except feral swine and Raccoon (Procyon lotor, Linnaeus). For raccoons the number of baits removed per 24h was reduced by 92% during the HOGHOPPER activation period. No other wildlife removed HOGGONE from HOGHOPPERS. During trials in which raccoon breaches occurred, an extended acclimation period was used. To minimize raccoon exposure risks, an abbreviated acclimation period of 14d should be used with the HOGHOPPER. This will decrease the likelihood that raccoons learn how to access HOGGONE from the HOGHOPPER. Further experimentation is needed to demonstrate the efficacy of toxic HOGGONE at controlling feral swine populations.