Contact Information: 

Dr. Fred Cunningham 

Supervisory Research Wildlife Biologist

Mississippi Field Station

P.O. Box 6099

Mississippi State, MS 39762-6099

Phone: (662) 325-8215 

FAX: (662) 325-8704

fred.l.cunningham@aphis.usda.gov

www.aphis.usda.gov/wildlife_damage/

nwrc/ 

Major Cooperators

 Animal Control Technologies Australia

 Archbold Biological Station

 Invasive Animals Cooperative 

Research Centre

 MacArther Agro-ecology Research 

Center

 Sul Ross State University

 Texas A&M University-Kingsville

 Texas Department of Agriculture

 Texas Parks and Wildlife Department

 University of Florida

 USDA/APHIS/Veterinary Services

 Wildlife Services Operations

Wildlife Services

Protecting People rotecting People

Protecting Agriculture rotecting Agriculture

Protecting Wildlife rotecting Wildlife

FY 2012

National Wildlife Research Center

United States Department of Agriculture

Animal and Plant Health Inspection Service

National Wildlife Research Center Scientists Provide Basic Ecological Information to 

Develop Feral Swine Damage Control Strategies.

Wildlife Services’ (WS) National Wildlife Research Center (NWRC) is the only Federal research organization devoted exclusively to resolving confl icts between people and wildlife 

through the development of effective, selective, and socially responsible methods, tools, 

and techniques

As increased urbanization leads to a loss of traditional wildlife habitat, the potential for confl icts between people and wildlife increases. Such confl icts can take many forms, including 

property and natural resource damage, human health and safety concerns, and disease 

transmission among wildlife, livestock, and humans.

The high reproductive rate and adaptability of feral swine has resulted in populations that 

have dramatically increased in size and distribution. This invasive animal now occurs 

across much of the United States where it causes a range of agricultural and environmental damage through depredation, rooting, and wallowing activities. Furthermore, feral swine 

compete with native wildlife and livestock for habitats, are carriers of exotic and endemic 

diseases, and transmit parasites to livestock and humans. It is estimated that feral swine in 

the United Statescause more than $1 billion in damages and control costs each year.

Applying Science and Expertise to Wildlife Challenges

Effects of Baiting on Feral Swine Culling Success—How feral swine respond to control 

operations is an important consideration in developing optimal management plans. To better understand feral swine behavior, NWRC scientists studied the effects of supplemental 

feeding/baiting on feral swine movements and the likelihood of baiting to reduce dispersal 

of swine under culling pressure on the Rob and Bessie Welder Wildlife Foundation (WWF) 

in San Patricio County, Texas. By placing global positioning system (GPS) collars on feral 

swine, scientists were able to track movement throughout control operations. Populationwide culling activities included trapping and shooting around a centralized bait station. 

Feral swine home ranges did not differ between the bait station site and other non-baited 

sites. However, the daily movement rates of feral swine at bait station sites were 39 percent greater than movement rates of animals in non-baited areas. Opposite to what was 

expected, baiting stations did not reduce movement in the treatment areas. WS does not 

recommend the use of baiting as an alternative to fencing for containing feral swine during 

culling activities.

Tuberculosis and Feral Swine—There is little information regarding the diseases and 

parasites found in feral swine populations in the Texas border region. This information 

is needed to understand risks from trans-boundary diseases and to devise and evaluate 

control strategies. Information from the Texas border region is of particular importance 

because of the natural movements of wildlife, legal movements of livestock, and illegal 

movements of animals and animal products from and to Mexico, where many diseases, 

including bovine tuberculosis, may be present in domestic livestock. Bovine tuberculosis 

is caused by the bacterium Mycobacterium bovis. In a recent NWRC study, approximately 

400 feral swine were opportunistically sampled for M. bovis in southern Texas. Though no 

evidence of M. bovis infection was found in the swine, researchers recommend continued 

periodic and strategic sampling of feral swine for M. bovis in high-risk areas since feral 

swine are capable of becoming reservoirs of the disease.

Improving Traps for Feral Swine—Without an effective registered toxicant in place, trapping continues to be one of the primary methods for controlling feral swine populations. As 

such, numerous trap designs are currently used to capture feral swine; however, drop nets 

had never been evaluated. In a study conducted in Oklahoma, NWRC scientists compared 

the effectiveness and effi ciency of a drop-net and a traditional corral trap for trapping feral 

swine. A mark and recapture analysis showed more swine were removed with drop-nets 

Feral Swine Damage Control eral Swine Damage Control 

Strategies trategies

Groups Affected By These Problems

 Consumers

 Livestock producers and farmers

 Meat processors

 Sporting organizations

 U.S. citizens and landowners

 Wildlife and natural resource managers
than with corral traps. Effi ciency estimates for the average time 

per capture were 1.9 and 2.3 hours for drop-nets and corral traps, 

respectively. Feral swine did not appear to exhibit trap shyness 

around drop-nets, which often allowed the researchers to capture 

entire sounders (family units) in a single drop. Use of drop-nets 

also eliminated capture of non-target species. Results of this 

study indicate that drop-nets are an effective tool for capturing 

feral swine.

Monitoring Feral Swine Populations with Mark-Recaptur—

Land managers often use a variety of lethal control methods 

to combat growing feral swine problems. NWRC researchers 

evaluated the use of the biomarker tetracycline hydrochloride 

(TH) and mark-recapture techniques for monitoring the effectiveness of feral swine control methods. Researchers established 

and observed feral swine bait stations containing TH-treated sour 

corn. TH is a palatable and ingestible antibiotic that establishes 

a permanent fl uorescent mark on growing bone and teeth. Using 

data on the number of feral swine observed consuming THtreated bait and the number of animals subsequently removed 

from the population with TH-marked teeth, researchers calculated 

population estimates. TH proved to be a suitable marker for 

mark-recapture estimates of feral swine. The technique also included several advantages over traditional population monitoring 

techniques, such as reduced animal capture and handling costs; 

the ability to euthanize captured animals instead of releasing 

them for future recapture; and the ability to employ a variety of 

recapture methods.

Feral Swine Activity Near Domestic Swine Facilities—A major 

concern with feral swine is their potential to maintain and transmit 

diseases to domestic swine. The domestic swine industry is 

dominated by operations that maintain some level of biosecurity. 

However, a portion of the industry is considered “backyard” or 

transitional production. It is these smaller operations that provide 

opportunities for disease transmission between feral and domestic swine through fence lines and contaminated surfaces. To help 

aid in disease management, NWRC researchers collected data 

on feral swine movements, habitat preference, and the infl uence of boundaries and corridors near 28 small-scale domestic 

swine facilities in Texas. Data from collared feral swine showed 

they preferred habitat characteristics commonly found surrounding domestic swine facilities. Feral swine also demonstrated a 

disproportionate use of specifi c vegetation types as compared 

to their availability during both wet and dry periods. Additionally, 

the presence of paved, 2-lane roads infl uenced movements of 

feral swine. This information aids in the development of targeted 

management and eradication strategies near domestic swine 

facilities, particularly in emergency situations such as disease 

outbreaks.

Selected Publications:

CAMPBELL, T. A., D. B. LONG, M. J. LAVELLE, B. R. LELAND, 

T. L. BLANKENSHIP, and K. C. VERCAUTEREN. 2012. Impact 

of baiting on feral swine behavior in the presence of culling activities. Preventive Veterinary Medicine 104:249–257.

CAMPBELL, T. A., D. B. LONG, L. R. BAZAN, B. V. THOMSEN, 

S. ROBBE-AUSTERMAN, R. B. DAVEY, L. A. SOLIZ, S. R. 

SWAFFORD, and K. C. VERCAUTEREN. 2011. Absence of Mycobacterium bovis in feral swine (Sus scrofa) from the southern 

Texas border region. Journal of Wildlife Diseases 47:974–978.

CAMPBELL, T. A., D. B. LONG, and G. MASEI. 2011. Effi cacy 

of the Boar-Operated-System to deliver baits to feral 

swine. Preventive Veterinary Medicine 98:243–249.

CARDENAS-CANALES, E., T. A. CAMPBELL, Z. 

GARCIA-VAZQUEZ, A. CANTU-COVARRUBIAS, J. 

FIGUEROA-MILLAN, R. W. DEYOUNG, D. G. HEWITT, F. C. 

BRYANT, and J. ORTEGA-SANTOS. 2011. Nilgai antelope 

in northern Mexico as a possible carrier for cattle fever ticks 

and Babesia bovis and Babesia bigemina. Journal of Wildlife 

Diseases 47:777–779.

LAPIDGE, S., J. WISHART, L. STAPLES, K. FAGERSTONE, 

T. CAMPBELL, J. EISEMANN. 2012. Development of a feral 

swine toxic bait (HOG-GONE®) and bait hopper (HOGHOPPERTM) in Australia and the USA. Proceedings of the Wildlife 

Damage Management Conference 14:19–24.

LAVELLE, M. J., K. C. VERCAUTEREN, J. W. FISCHER, 

G. E. PHILLIPS, T. HEFLEY, S. E. HYGNSTROM, S. R. 

SWAFFORD, D. B. LONG, and T. A. CAMPBELL. 2011. 

Evaluation of fences for containing feral swine under simulated depopulation conditions. Journal of Wildlife Management 

75:1200–1208.

LONG, D. B., and T. A. CAMPBELL. 2012. Box traps for feral 

swine capture: a comparison of gate styles in Texas. Wildlife 

Society Bulletin 36(4):741-746.

MOCZYGEMBA, J. D., D. G. HEWITT, T. A. CAMPBELL, 

J. A. ORTEGA-S., J. FEILD, and M. W. HELLICKSON. 2012. Home ranges of nilgai antelope (Boselaphus 

tragocamelus) in Texas. Southwestern Naturalist 57:26–30.

RAMIREZ, E. R., M. C. DOMINGUEZ-BRAZIL, C. W. LAWSON, S. M. BURNS, R. GUARNEROS-ALTOMIRANO, 

S. J. DEMASO, W. P. KUVLESKY, Jr., D. G. HEWITT, J. A. 

ORTEGA-S., and T. A. CAMPBELL. 2012. Home ranges of 

female Rio Grande wild turkeys in southern Texas. 

Southwestern Naturalist 57:198–201.

REIDY, M. M., T. A. CAMPBELL, and D. G. HEWITT. 2011. 

A mark-recapture technique for monitoring feral swine 

populations. Rangeland Ecology and Management 

64:316–318.

SANDERS, D. L., F. XIE, R. E. MAULDIN, L. A. MILLER, 

M. R. GARCIA, R. W. DEYOUNG, D. B. LONG, and T. A. 

CAMPBELL. 2011. Effi cacy of ERL-4221 as an ovotoxin for 

feral swine. Wildlife Research 38:168–172.

WYCKOFF, A. C., S. E. HENKE, T. A. CAMPBELL, D. G. 

HEWITT, and K. C. VERCAUTEREN. 2012. Movement and 

habitat use of feral swine near domestic swine facilities. 

Wildlife Society Bulletin 36:130–138.

The U.S. Department of Agriculture is an equal opportunity employment provider and employer
The U.S. Department of Agriculture is an equal opportunity employment provider and employer

Major Research Accomplishments:

 WS evaluated the use of bait stations to contain feral 

swine during simulated culling activities and found bait 

stations to be ineffective at containing animals, but 

facilitated removals.

 WS determined that drop-net traps were more successful in capturing feral swine than traditional corral traps. 

Researchers also found box traps with rooter gates 

captured more juvenile feral swine, resulting in more 

total captures than box traps with side-swing gates.

 WS studied feral swine movement and habitat use near 

domestic swine facilities and found animals preferred 

habitat characteristics commonly found surrounding 

domestic swine facilities.

 WS found no evidence of Mycobacterium bovis in feral 

swine populations within the southern Texas border 

region.

 WS developed a mark-recapture population monitoring technique that complements feral swine damage 

management activities.

 WS evaluated ERL-4221 as an ovotoxin for feral swine 

and found the chemical to be ineffective at reducing 

total ovary mass, number of follicles, and number of 

corporal lutea.