Feral Pig Control: Present and Future Article by James C

TEXAS WILDLIFE B o rderlands news

Borderlands Research Institute for Natural Resource Management

Feral Pig Control: Present and Future Article by James C. Martin, Justin A. Foster, and Ryan S. Luna

andowners across Texas and around exist and can be modified for almost any already out of control. In order to control the nation are dealing with the recent situation. The Texas Agrilife Extension web feral pig populations, at least 70 percent of explosion in the feral pig population. site is a good resource for trap design and the population must be removed each year CommonlyL referred to as the “pig bomb,” trapping procedures. While trapping can be to maintain the current population size and this rapid population growth has resulted highly successful, precautions should be taken a yearly take of at least 75 percent being in an estimated population of feral pigs in in how the animals are dealt with after the needed to reduce the population in a given Texas upwards of 2.5 million animals. Texas’ capture; trapped feral pigs can be aggressive area. Large scale shooting of feral pigs such as population makes up approximately half of and despite popular belief can and will jump that conducted on many private ranches and the nationwide feral pig population estimate. fences as high as 4.5 feet tall when pressured. by USDA Wildlife Services can and in some High reproductive output and fecundity Shooting, via ground or helicopter, can be cases does have a drastic effect on populations along with misguided and illegal movement highly effective at reducing pig populations in a localized area. of animals has made this rapid expansion of in an area. A distinction must be made here Recreational hunting while not effective population and distribution possible. that “shooting” and recreational hunting as a control or management tool for the state Pigs first arrived in the United States in are different in the context of population as a whole may help to reduce predating pigs the 1500s with the first Spanish explorations. reduction or control. Despite recreational in agricultural areas and serve as a way in Accidental releases and losses to Indian raids hunting of feral pigs being legal for many which landowners can recoup some of the allowed for the first individuals to begin years, the feral pig population continues losses due to feral pig damage. Recreational the process of becoming feral. Populations to grow. While hunting is a great tool for hunting has caused some issues with the of feral pigs slowly grew but were probably the management of game species with transfer of feral pigs to new areas. Researchers limited in numbers by predatory animals; stable populations, it might not be the best have found that some pigs killed in northern most of which are only now recovering from method to control a population that is states where they have only recently been near eradication and subsistence seen have close genetic similarity hunting by Native Americans to those in southern states. This and frontiersmen. Without leads managers to believe that these constraints, an increase in feral pigs may be being illegally available forage from agriculture transported across state lines and clandestine releases on both for the purpose of populating public and private property, an area for future hunting. This the population was able to not only aids in the expansion reach the levels we now face. of feral pigs but also potentially Natural resource managers and transmits diseases into an area researches are now working to which could pose risks to the develop more effective ways to health of humans, livestock and deal with the growing issue. wildlife. Trapping can be a cost effective A potential game changer in and relatively simple solution for the way we control feral pigs is dealing with feral pig problems under development through on private property. Many the cooperation of the USDA designs and trapping techniques National Wildlife Research

32 TEXAS WILDLIFE january 2015 b o rderlands news

Center, Texas Parks and Wildlife Department and 50 percent mortality in pen trials, while However, none of these have been tested and Animal Control Technologies Australia. current formulations are resulting in 80 in areas where sympatric populations of feral This team, along with assistance from to 90 percent mortality. Additional testing pigs and black bears occur, as is the case in east graduate students from the Borderland of these formulations is needed before the Texas. This issue may be addressed by a new Research Institute at Sul Ross State University group is able to request an Experimental Use device produced by Wildlife Management is investigating the use of sodium nitrite as a Permit (EUP) from the EPA to allow testing Solutions LLC, the Hog Annihilation toxicant. Sodium nitrite is commonly used as outside the pens on free ranging feral pigs. Machine or HAM uses sound recognition a meat preservative and has been thoroughly Registration of sodium nitrite as a toxicant is software to determine when pigs are near the investigated for its safety for human handling not expected for another three to five years if feeder. When pigs are present the machine and consumption. These investigations have one of these current formulations repeatedly opens the feeder doors to allow access to the paved the way for the potential use of sodium produces acceptable results. feed, upon the animals leaving the machine nitrite as a toxicant by eliminating the need While research into the toxicant itself has resets and shuts the doors locking out other for studies regarding human safety. Focal been the main focus over the last few years, it species. The device is also equipped with a points of the ongoing research are stability is not the only important piece of the puzzle. defense model that electrically charges the and palatability, efficacy, non-target risk Delivering the toxic bait to feral pigs and only device to address the bear issue. Testing on mitigation and risk to secondary consumers. feral pigs is becoming increasingly important. the feeder system is ongoing but may prove It is important to note here that private use of Researchers at the Kerr Wildlife Management effective in reducing the non-target risk. sodium nitrite for pig control would be illegal Area have evaluated the effects of sodium Currently no toxicants are registered in the and ineffective due to the instability of the nitrite on multiple native species and have United States for the control of feral pigs and chemical. reported on the risk of non-target mortality. it will be at least three to five years before there Currently three newly developed To limit this risk, non-target exclusion is one available. Despite what many think, formulations of the toxicant are being tested devices are being investigated. The Boar toxicants will not be the silver bullet in the at TPWD’s Kerr Wildlife Management Area Operated System (BOS™) (Giovanna Massei), battle against feral pigs, but just another tool in Hunt, Texas. These formulations have Hog Hopper™ (Animal Control Technologies in the landowner and resource manager’s tool shown significant improvement over previous Australia), and the Non-target Exclusion box. However, control of feral pigs through versions and have met the Environmental Device (NED) have all been the subject of integrated management and the utilization of Protection Agencies requirement’s for various publications and have been shown to all of our available tools can have a profound efficacy in preliminary trials. Results of meet the needs of restricting access of most impact on the population. previous formulations ranged between zero non-target species that occur in Texas.

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