Southern region land-grant researchers finding solutions to control feral hogs

V. Todd Miller

BATON ROUGE, LOUISIANA

 Feral hogs are a nuisance in many areas of the United States, causing billions of dollars in damage. They are reported in 35 states with a population of approximately nine million hogs causing billions in damages each year. They eat crops, dig up trees and devour food that other animals depend on.

Feral swine can significantly damage native flora and fauna through their rooting behaviors or indirectly by facilitating the spread of invasive plants, altering soil and water resources and limiting regeneration of native plants. Habitat degradation by feral swine may influence the diversity and occurrence of native wildlife communities. Feral swine also carry and transmit diseases such as brucellosis and pseudorabies virus that pose significant risks to the health of many wild and domestic animals.

Feral Hogs cause an estimated $1.5 billion in economic damages annually across the United States, according to the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service. Land-grant researchers from the southern region are developing solutions to manage this infestation.

Feral hogs have been part of the American landscape since the 1500s when early explorers and settlers imported swine as a food source. Free-range livestock management practices and escapes from enclosures led to the first feral hog populations taking hold.

In the 1900s, the Eurasian wild boar was introduced to some states for sport hunting. Modern feral swine are a combination of escaped domestic pigs, wild boars and hybrids of the two.

Arkansas Forest Resources Center conducts multi-state damage assessment

To serve as a baseline for feral swine damage assessments to private landowners and help guide management practices, the Arkansas Forest Resources Center in Monticello led a multi-state survey of 4,500 landowners to gauge economic damage to croplands, forestlands, pasturelands/livestock and their combinations.

The study, “Assessing feral swine damage in the western gulf region of Arkansas, Louisiana, and Texas,” was published in the Biological Invasions journal in January and estimates feral swine damages over five years across all of Arkansas and Louisiana and 38 counties in east Texas. The project was initiated by Nana Tian, assistant professor of forest economics in the College of Forestry, Agriculture and Natural Resources at the University of Arkansas at Monticello and researcher for the Arkansas Agricultural Experiment Station. Her research partners were Jianbang Gan, professor in the department of ecology and conservation biology at Texas A&M University’s College of Agriculture and Life Sciences, and Gordon Holley, professor in the School of Agricultural Sciences and Forestry at Louisiana Tech University.

The survey estimates private landowners’ average agricultural cropland damage in the past five years was $28 per acre in both Arkansas and Louisiana and approximately $25 per acre in east Texas. The most reported feral swine damage to agricultural crops was to corn, soybeans, rice, wheat, hay, silage and forage crops.

Feral hog baits are Louisiana’s answer

The Louisiana Department of Wildlife and Fisheries estimates the state’s population of feral hogs at more than 900,000. The damage estimates based on a Louisiana State University AgCenter survey to Louisiana’s commodity production are $66 million and other non-production losses are at almost $25 million.

LSU AgCenter researcher Glen Gentry along with the LSU Department of Chemistry is working on a bait and delivery system to help reduce the population of feral hogs. The baits are soft and can be swallowed whole by the pigs, which reduces the chances of crumbs being consumed by other animals.

The baits have sodium nitrite, a common food additive in products, such as bacon. It is lethal to pigs at fairly low levels.

The researchers had to look at several factors when developing the bait. One involved choosing a formula that was more attractive to hogs than other animals and was based on features like smell and texture. 

Louisiana’s next steps

The LSU AgCenter team plans to commercialize the bait system once they are satisfied with its performance. The product will then be patented and go through federal and state approval processes. A landowner will probably need to get some form of pesticide applicators license to distribute the bait.

Oklahoma tracking feral hogs 

The Wichita Mountains Wildlife Refuge (WMWR) was established in southwestern Oklahoma in 1901 for “the protection of game animals” and is a key refuge for native bison conservation. Feral swine were first documented at WMWR in 1993. Feral swine are a serious threat to native habitats and wildlife, and their direct and indirect impacts on native faunal communities at WMWR have not been formally assessed. Managers have controlled feral swine with 200 plus feral swine removed each year. Despite considerable effort and costs, swine have persisted and impacts of control on swine have not been put into formal data. 

Oklahoma State University’s research goal is to quantify feral swine space use patterns within the refuge and evaluate the effects of feral swine on the diversity of the native mammal community to inform management of the refuge. Remote game cameras at 99 random sites within the refuge will be used to document feral swine and other native mammals’ space use patterns. Additionally, small mammals have been live captured at approximately a quarter of the sites to document small mammal diversity. The process of classifying the camera images and summarizing results from the first field season is in progress.

Next Steps in Oklahoma

Sampling will be repeated, along with habitat sampling in May-August 2023. Occupancy modeling will be used to evaluate environmental factors driving variation in swine space use. For native mammals, data will be analyzed to estimate species richness using an approach that accounts for species that may have been missed. After the 2023 sampling is completed, data and research results will be disseminated to natural resource managers and the scientific community.

South Carolina’s Wild Hog Task Force

To address the issues of expanding wild hog populations and their negative impacts, the South Carolina Wild Hog Task Force was created to coordinate education, research and management efforts to reduce problems associated with wild hogs in the Palmetto State. The task force is comprised of 21 different state and federal agencies, agriculture and natural resources associations and conservation groups led by Clemson University and U.S. Department of Agriculture Wildlife Services.

Clemson University continues to provide leadership, coordinating the South Carolina Wild Hog Task Force to coordinate education, research and management programs to reduce damage caused by wild hogs in South Carolina. Future research will focus on effective methods to reduce wild hog damage and track actual damage in the state. ∆