With the expansion of feral hog populations comes growing concern over the effect that they will have on native habitats and wildlife. Resource managers have been looking for new tools to help in the control of feral hog populations, and toxicants have been at the forefront of research and development for several years. However, there has been limited success and there are currently no registered toxicants available for control of feral hogs. BRI, in conjunction with Texas Parks and Wildlife is currently conducting research into one such control method, sodium nitrate, including investigations into it’s effectiveness, the potential for detrimental effects on non-target species, and the usefulness of attractants to increase efficiency of toxicant use.

The use of attractants for trapping and hunting wildlife has been shown to be widely successful. One area of particular interest is the potential use of pheromones as attractants due to their species specific nature. We are testing the effects of attractants produced from the carpal glands of feral hogs on a group of captive feral hogs. We will look at the effect that the attractant has on group feed consumption as well as if effectiveness of the attractant changes as distance from the feeder to available cover changes. The information obtained from this study will give us insight into the potential use of carpal gland secretions as attractants for feral pig control and how distance to cover could increase or decrease the efficacy of control efforts.

We are also investigating three formulations of sodium nitrate in pen trials using captive feral pigs. Preliminary evaluations show that none of the formulations tested resulted in the 90% mortality necessary for EPA registration with the highest mortality observed being approximately 42% of test subjects.
The sensitivity of turkey vultures to sodium nitrite is not known and with ongoing research into the use of sodium nitrate as a feral hog toxicant the need for information on the risk of exposure is high. Feeding behaviors of turkey vultures and other raptor species will be observed by remote cameras for two treatment groups of carcasses to obtain data on the order organs are consumed and shown preferences among scavenger species. Sodium nitrate residual levels in feral pig tissue in the areas of the body that the vultures are observed feeding on will be analyzed to show the potential risk of secondary exposure based on carcass usage.

Through this research we will provide resource managers with relevant information on the utility of feral hog population control methods. Additionally, by providing information on how using toxicants in feral hog control may have detrimental effects on native species, resource managers may be able to alter their methods in the field to minimize these risks.