Governmental Provisions to Manage and Eradicate Feral Swine in Areas of the United States

Abstract

Feral swine (wild hogs) are one of the most widely distributed free-ranging mammals in the world. In the United States, feral swine serve as game animals for the sport of hunting in some areas, while they are nuisance species at other locations. Increasing feral swine populations creates negative impacts to growing crops, native plant communities, and wildlife. Feral swine can also serve as reservoirs for a number of bacterial and viral diseases that can infect wild animals, livestock, and humans. The US state governments are adopting statutes and regulations to reduce the growth and dispersal of feral swine populations. An analysis of these provisions suggests that while they seek to control feral swine populations, they are unlikely to provide any significant relief from damages to crops and native ecosystems. More localized reduction plans and a national disease control program are suggested to assuage damages being wrought by these invasive animals.

Introduction

Feral swine (Sus scrofa) are an invasive species in the United States with an estimated five million animals established in 39 US states (Morthland and McSpadden 2011; USDA 2013a). Commencing in the sixteenth century, domestic swine were introduced to the United States from Europe by explorers and settlers as a source of food. During the last century, ranchers and sportsmen imported the Eurasian (Russian) boars as a huntable game species and released them into fenced and unfenced areas (Fogarty 2007). Wild Eurasian boars have interbred with swine populations, and all combinations of wild hogs are referred to as feral swine (Hamrick et al. 2011; Carson 2013).

Because of their fecundity and adaptability to a wide range of habitats, feral swine populations have flourished (Timmons et al. 2012b; USDA 2013b). Rapid increases in feral swine numbers and distribution have alarmed agricultural producers, environmental groups, and public health officials. These groups have petitioned the US state legislatures for new legislation and regulations to safeguard agricultural crops, ecosystems, and public health. In addition, the federal government has been asked to assist with controlling the numbers of feral swine due to the damages they are causing (Shaw 2013). This paper examines policies adopted to control feral swine populations. Through an examination of three categories of regulatory provisions to reduce feral swine populations, the diverse objectives of state governmental approaches are analyzed. The discussion offers a critique of the US state regulations and a brief comparison with policies adopted by the Australian government. This discloses that the US federal government has lagged in its efforts to address this invasive species. The analysis also suggests that the actions by most state governments are not meaningfully reducing populations, and so are not significantly lessening damages caused by feral swine.

Recreational Sport Versus Invasive Pest

Hunting

In the United States, over 2.2 million hunters spent 34 million days hunting feral swine, raccoons, foxes, groundhogs, and coyotes in 2011 (US Department of the Interior 2013). Each US state is able to adopt its own laws regarding the status of feral swine. Hunters want robust numbers of feral swine, and landowners encourage the presence of feral swine due to the income derived from selling hunting leases (Mapston 2004; Plasters et al. 2013). Persons who view feral swine as a species for recreational hunting tend to oppose efforts to reduce populations, despite significant reductions in farm income from feral swine damages (Adams et al. 2005).

In states with established feral swine populations and significant revenues from hunting, the responses to damages are provisions that preclude the transport and release of feral swine to new areas. Simultaneously, other state laws and regulations encourage hunting and sanction fenced preserves where hunters pay for the privilege of taking feral swine. Some states have adopted legislative provisions that operate to curtail the elimination of too many animals, require licenses, have limited hunting seasons, and require field tags for killed animals. A few states retain penalties for persons who illegally injure or cause the death of a feral swine (West Virginia Code 2013). These hunting provisions promote an increase in feral swine populations.

Crop and Environmental Damages

The most perceptible damages from feral swine populations involve the destruction of agricultural crops, native species, and ecosystems (Timmons et al. 2012a; Krull et al. 2013). In the United States, the expansion of feral swine has prompted the US Department of Agriculture (USDA) to propose a nationally coordinated swine damage management program in cooperation with agencies and organizations at the state level (USDA 2013b), and the US state governments have examined the damages from feral swine in an effort to develop regulations to reduce populations. In 2000, the annual economic loss due to feral swine damage plus the cost of their control in the United States was estimated to be over US $1.5 billion (Pimental 2007; USDA 2013a).

Feral swine can have a significant impact on native species and ecological systems (Timmons et al. 2012a). Disturbances by feral swine affect local vegetation composition and decrease the diversity of woody plants and animal species (Siemann et al. 2009; Krull et al. 2013). Damage to native animals can be costly. Feral swine eat invertebrates, salamanders, frogs, snakes, turtles, fish, crabs, rodents, muskrats, and in some cases, white-tailed deer fawns and young livestock (Seward et al. 2004). They can adversely impact ground-nesting birds (Adams et al. 2005; Kammermeyer et al. 2011), reduce successful hatching of alligators (Elsey et al. 2012), and seriously threaten the nest success of several threatened and endangered sea turtles (Engeman et al. 2010). Another danger is the destruction of levees that protect people and property from flood waters, including levees in the New Orleans region of Louisiana (Shaw 2013).

Disease Transmission

Feral swine serve as a reservoir for diseases (Musante et al. 2014). They can carry over 30 diseases and 37 types of parasites that can be transmitted to livestock, people, pets, and wildlife (Corn et al. 2009; Leiser et al. 2013; USDA 2013a). Feral swine carrying a disease may end up decimating an endangered species (Plasters et al. 2013). Eight diseases that can infect humans are brucellosis, leptospirosis, salmonellosis, toxoplasmosis, balantidiasis, trichinosis, trichostngylosis, and sarcoptic mange (Seward et al. 2004).

The diseases of most concern are pseudorabies and swine brucellosis (Leiser et al. 2013; Musante et al. 2014). Attention is needed to prevent pseudorabies, a virus that is spread through the contact of infected animals with animals that are not infected, from being transmitted to commercial hog facilities (Witmer et al. 2003; van Campen and Rhyan 2010; Wyckoff et al. 2012). Although it is not fatal to adult swine, it weakens animals and causes spontaneous abortions and stillbirths (USDA 2005). Swine brucellosis, a bacterial infection that is transmitted through reproductive discharges, can infect cattle if they come within close contact with diseased swine (USDA)2005). Expanding feral swine populations might serve as a reservoir for infection of other native wildlife and domestic animals (Olsen 2010), leading to losses in reduced beef and milk production calculated in billions of dollars (USDA 2012).

Feral swine infected with brucellosis also pose dangers to humans (CDC 2009). The Centers for Disease Control warn hunters to avoid direct contact when dressing and butchering an animal (CDC undated). Because an animal’s blood, fluids, and tissues may be infected, care must be used to avoid contracting brucellosis (CDC undated; USDA 2012). Research also suggests that in some areas, feral swine harbor Campylobacter pathogens that could infect hunters during handling and processing of a carcass (Jay-Russell et al. 2012). Diseases carried by feral swine may be transmitted from water and cultivated fields to other animals and deposited on edible plants such as lettuce and spinach to adversely affect humans (Jay et al. 2007; Benjamin et al. 2013).

The US State Legislation to Control Populations

While the US federal government is studying feral swine “to address the need for a national feral swine damage management program to protect agriculture, natural resources, property, and human health and safety” (USDA 2013b), there is no policy on feral swine (USDA 2013c, p. 27). Rather, under the US federal system, regulatory authority resides with the states (USDA 2013c, p. 80). Due to the increasing financial losses associated with feral swine, the US state governments have adopted three categories of regulatory provisions to address damages from feral swine. The examination of these provisions illuminates options for governments in determining whether to offer greater support for agricultural production and the preservation of ecosystems.

Encouraging Hunting

State regulations vary on their classifications of feral swine. They have been classified as game animals, wild animals, nuisance animals, outlaw quadrupeds, non-game animals, feral animals, exotic animals, and other designations (Wildlife Society 2012). These different classifications subsequently affect regulatory controls for feral swine populations. In areas where hunting is important, governments may decline to take meaningful action to address damages to crops and ecosystems. But in other areas, governments are encouraging the reduction of feral swine populations by relaxing hunting regulations on private and public property (Table 1). Some states allow hunting year-round on private property with no bag limit, allow landowners and lessees to eliminate feral swine on their properties without a hunting license, and expand the weapons that may be used to kill feral swine. The use of dogs for hunting feral swine and allowing hunting at night can also help in reducing populations. The Texas legislature passed a bill in 2011, which allows landowners to take swine by shooting from a helicopter (Texas Administrative Code 2013), while Oklahoma law allows the use of aircraft (Oklahoma Statutes 2013).

Table 1.

US state provisions regulating feral swine

State	Source	Encouraging hunting	Precluding activities	Eradication provisions
AL	Ala. Admin. Code ch. 220-2	Expansive weapons, no bag limit, use of bait, hunting areas	No transport beyond boundaries, no release on other property
AR	Ark. Code Ann. §§ 2-38-502; 2-38-504	Any time on private property with permission	No transport or release
CA	Cal. Fish & Game Code § 2118		No import, transport, or release	No possession
DE	Del. Gov. Reg. 201:66 (proposed)	Yes, for eradication	No release, no hunting fees
FL	Fla. Admin. Code 5C-3.007, 5C-21.010, 5C-21.002, 5C-21.015, 68A-4.002, 68A-15.006	Private land at night, season for using dogs	No transport, disease test for moving and import to a preserve	Dealers registered, inspection of game reserves
GA	Off. Ga. Code Ann. §§ 27-2-31, 27-3-24: Ga. Rules & Regs. r. 40-13-2.09	Night light to locate, possibility of baiting	No import without disease test
IA	Iowa Admin. Code ch. 77			Identification device and fee
IL	Ill. Admin. Code §§ 8:105.90, 17:1-700		No import without disease test, no hunting fees
IN	Ind. Admin. Code §§ 312:9-3-118.6, 345:1-3-13	Any time on private property with permission	No import, transport or release	No sales, trade, or compensation
KS	Kan. Ann. Stat. § 47-1809; Kan. Admin. Reg. § 9-7-7		No import, transport, or release	No possession, no hunting preserves
KY	Ky. Rev. Stat. § 150.186		No import, transport, or release	No possession
LA	La. Admin. Code §§ 76:V-127, 76:V.130, 76:XIX.101, 76:XIX.111	Year-round, sometimes after sunset, use of dogs, trapping	No relocation
MD	Code of Maryland Reg. § 15:11-16.01		No import	No possession or sales
MI	Mich. Comp. L. Serv. §§ 287.731, 287.841		No import unless permission, no release
MN	Minn. Admin. Code r. 1700.2700, 1700.2850, 6216.0250		No import, purchase, or transport	No possession
MS	Miss. Code Ann. §§ 49-7-31.5, 49-7-140; Code of Miss. Rules r. 40-002-07	No license, nuisance animals by landowners, any weapon, bait, dogs, at night	No import, release, or transport without permit
MO	Mo. Ann. Stat. §§ 270.170, 270.400; Mo. Code St. Reg. tit. 3, § 10-7.433	On property or with owner’s permission	transport only farm to farm or to slaughter	Permit for preserve
NC	N.C. Gen. Stat. § 113-291.12; N.C. Admin. Code §§ 15A:10B.0303, 15A:10H.0301	No closed season	No transfer or release
NE	Neb. Rev. Stat. Ann. § 37-524.01		No release	No profits
NH	N.H. Rev. Stat. Ann. §§ 467:3, 467:5			Liability under trespass
NM	N.M. Stat. Ann. § 77-18-6		No import, transport, release, or hunting fees	No breeding or sales
ND	N.D. Century Code § 36-26-03		No import or transport	No possession or profits
NV	Nev. Admin. Code § 503.110		No import or transport	No possession
NY	N.Y. Env. Cons. Law § 11-0504; N.Y.S. Register 35:50:4 (proposed)		No import or transport	No possession after 2015
OH	Ohio Rev. Code § 1533.721; Ohio Admin. Code r. 1501:31-15-02, 1501:31-15-17	Year-round, trapping	No release	No captivity or sale without permit
OK	Okla. Stat. Ann. tit. 29, §§ 4-135; 4-107.2; Okla. Admin. Code §§ 35:15-34-5, 800:25-37-12	No license on owned- leased property, at night, loaded firearms, aircraft	Transfer by licensed transporter
OR	Ore. Revised Stat. §§ 497.655, 498.180, Ore. Admin. Rules r. 635-056-0050	County animal controls programs	No import, transport, or hunting fees
PA	Pa. Admin. Code § 7:3.142, 58:137.2		Permit required for import, no release	Sterilization of males in preserves
SC	S.C. Code §§ 50-16-20, 50-16-25; S.C. Code Reg. §§ 27-1013, 123-40	Limited use of dogs, open game season, at night	Import disease test, no transport or release without permit	No possession, no sale
TN	Tenn. Code Ann. § 44-2-102; Tenn. Comp. R. & Regs. r. 1660-01-15-.01		Import disease test	No import of diseased animals
TX	Tex. Parks & Wild. Code §§ 42.002, 42.005, 43.1075, 43.158; Tex. Admin. Code §§ 4:55.9, 31:65.151, 31:65.152	No license for landowners and their lessees and agents, use of helicopter	No movement without authorization
UT	Utah Admin. Code r. 58-1-8		Import disease test
VA	Va. Admin. Code § 4:15-30-40		Permit for import	No possession, permit for sale
VT	Vt. Stat. Ann. tit. 10, § 4709		No import	No possession
WA	Wash. Admin. Code §§ 16-54-065, 16-54-111, 232-12-017		No import, transfer, or release	Possession illegal, no sale
WI	Wis. Admin. Code nr. 16.15, 40.04		No import or hunting fees	No possession except under license
WV	W. Va. Code § 20-2-12; W. Va. Code State R. § 58-64-7			license for preserves, liable for damage

The Oklahoma legislature enacted a law in 2012, which authorizes the use of the Judas tagging system (Oklahoma Statutes 2013). The Judas system allows a landowner to fit trapped swine with radio collars and release them onto the same property on which they were captured. The released collared animal eventually associates with other feral swine, so that a landowner or hunter can locate a group of animals. This enables landowners to set corral traps in appropriate locations and to eliminate a group of animals.

The ecological benefits from reducing feral swine populations through hunting can be substantial. The removal of feral swine from a special wetland habitat in Florida resulted in the reduction of damages by 60 % (Engeman et al. 2007). Benefits may extend beyond the numbers of animals killed as research suggests that hunting can lead feral swine to move away from an area (Hayes et al. 2009). This can reduce damages to agricultural crops or sensitive ecosystems.

Precluding Activities

To slow the dispersal of feral swine into new areas, many states have enacted laws with penalties that preclude the import, transport, or release of animals (Table 1). To suppress the spread of disease, most states prohibit the import of feral swine into the state or prohibit the import of live feral swine unless permission is granted or there is proof of a negative pseudorabies and brucellosis test. A majority of states preclude the transport of live feral swine within the state (with exceptions), so that it is illegal to relocate animals to new areas. In an effort to curb swine releases, several states have increased the penalties for release of feral swine. These provisions have helped in curtailing persons from transporting animals to new areas for hunting.

Several states have adopted provisions intended to preclude or discourage activities that are dependent on feral swine populations. The most common is a provision that precludes persons from charging hunting fees to reduce the situations in which persons receive remuneration from feral swine. States adopting this provision discourage the introduction of feral swine into new areas, discourage the establishment of game preserves stocked with feral swine, and diminish incentives for maintaining feral swine populations. Other states have adopted distinct hunting provisions for wilderness areas, which allow more aggressive controls to be applied in areas suffering greater damages. Two counties in Texas have decided to pay persons US $5.00 per animal-harvested crops (Caldwell County Feral Hog Task Force 2013).

Specialized Eradication Provisions

Due to crop losses inflicted by feral swine, which are borne by landowners and crop growers, it is advantageous to eradicate this invasive species in some areas. State and local governments have choices in determining whether to go beyond hunting regulations and precluding activities in an attempt to eradicate feral swine. Most eradication efforts are adopted and paid by persons who want to control the numbers of animals damaging crops. In some instances, governments may also contribute funds for eradication efforts.

An initial provision of an eradication program is a law or regulation that precludes persons from possessing live feral swine (Table 1). New York, with only four breeding populations of feral swine, adopted this provision in 2013 with the goal of completely eliminating feral swine in the state (New York Environmental Conservation Law 2013; USDA 2013d). Subsequent proposed regulations would preclude the hunting and trapping of feral swine in New York except as authorized by appropriate officials. This prohibition would discourage individuals from illegally releasing feral swine into new areas (New York Department of Environmental Conservation 2013). Furthermore, the elimination of hunting prevents hunters from causing groups of feral swine to scatter in a manner that frustrates eradication efforts involving the trapping of a group of animals in a corral (New York Department of Environmental Conservation 2013).

States with established feral swine game preserves may adopt provisions to control situations in which animals escape. Iowa requires owners of feral swine to have an electronic identification device implanted beneath the skin or hide of each animal, the registration of animals, and the payment of a yearly registration fee (Iowa Administrative Code 2013). New Hampshire has a statute under which possessors of feral swine, who allow an animal to escape an enclosure are liable for damages from its trespass onto other properties (New Hampshire Revised Statutes Annotated 2013). Yet, state agencies that attempt to limit the growth and distribution of feral swine populations to protect crops and wildlife often encounter opposition from the hunting community. In 2013, the Pennsylvania Game Commission announced plans for the complete eradication of feral swine from the state (Pennsylvania Game Commission 2013). Owners of game preserves saw the proposal as a threat to their livelihoods. Before the Game Commission’s final regulation could go into effect, the Pennsylvania legislature passed a bill saying that the Game Commission has “no authority to promulgate regulations on swine hunting preserves” (Pennsylvania Statutes Annotated 2013). Hunting preserves in Pennsylvania are able to continue with their business operations and provide owners of rural lands a source of income.

Discussion

Inadequacy of the US State Responses

Over the last 20 years, feral swine populations have exploded across the United States leading to greater crop losses, habitat alterations, and risks of disease. Individual US state governments have sought to combat these damages by enacting assorted provisions to regulate feral swine populations. Three categories of regulations may be distinguished: hunting controls, precluding activities, and eradication efforts. The provisions vary considerably among the states due to different classifications of feral swine as game animals, wild animals, nuisance animals, and other designations.

An analysis of provisions to encourage hunting discloses that they have not been adopted by all states. Furthermore, most states have not incorporated several ideas that would make it easier for persons to harvest feral swine. Omitted ideas include eliminating requirements for licenses, eliminating tagging requirements, expanding hunting seasons, and allowing for the use of additional devices for hunting. Because the number of hunters in the United States is declining while the numbers of animals available to be hunted are increasing (Responsive Management/National Shooting Sports Foundation 2008), more encouragement might be offered to persons who wish to hunt feral swine. If a state desires to reduce existing feral swine populations, then it might proceed to relax hunting requirements for feral swine.

Yet, even with more encouragement for hunting, feral swine populations may not be reduced because they are so prolific. Populations may need to be reduced by 70 percent annually just to maintain a stable population size (Wildlife Society 2012; Illinois Department of Natural Resources 2013). Some hunters only want to harvest a few animals (Holsman et al. 2010). Research suggests that hunters will not be able to harvest sufficient numbers of animals on a sustained basis to reduce populations (Campbell and Long 2009).

The analysis of the second category of regulatory options that preclude the import, transport, and release activities discloses that these actions do not constitute meaningful efforts to reduce feral swine populations. These exclusionary actions reduce the introduction of feral swine into new areas rather than addressing reproduction rates. Another problem with these regulations is that some states have multiple agencies regulating feral swine (Wildlife Society 2012). While one agency may support preserving animals for hunting, another may be attempting to offer support for activities to reduce crop damages (Wildlife Society 2012). Given the conflicting objectives, many states are not offering bona fide support to the reduction of feral swine populations.

States also are having difficulties in enforcing regulations (Plasters et al. 2013). Individuals continue to engage in prohibited activities that assist feral swine in multiplying. Problems with violators who were illegally releasing feral swine prompted New York to propose a rule to make it illegal to hunt feral swine. This would eliminate any incentive to have feral swine in the state. If a state intends to reduce feral swine populations, then efforts beyond hunting and exclusionary measures may be needed.

The eradication efforts noted in the third category of regulations can assist in reducing numbers. Their appropriateness will depend on how many feral swine are in the state and the level of support for hunting. Those areas with low numbers of feral swine may be able to prevent the establishment of new populations and eradicate existing populations. While these efforts can be costly, they can markedly reduce damages so that they offer long-term benefits.

More significant is the absence of provisions addressing more drastic measures such as toxicants and fertility control agents. Both Australia and New Zealand have employed poisons in programs to reduce numbers of invasive species, including feral swine (Eason et al. 2010; Koichi et al. 2013). While a few of these measures have been used in some areas in the United States, there is no approved toxicant for use (Campbell and Long 2009), and the measures may be controversial. Poisons may be linked with secondary poisonings and may cause animals to suffer (Eason et al. 2010; Koichi et al. 2013), but a more significant problem is that nontarget animals can consume most of the bait (Campbell et al. 2006). Research continues on feeding devices that allow feral swine to consume poison bait while minimizing consumption by other species (Lapidge et al. 2012).

The most surprising observation is that despite the concerns about feral swine as carriers of brucellosis, tuberculosis, and pseudorabies that could spread to domesticated farm animals, the US federal government has not developed a feral swine disease control program to reduce the risks of a disease outbreak. To address disease concerns, the federal government might develop a disease prevention program that would establish federal controls on the movement of feral swine. The program could also delineate other provisions to reduce disease threats, which would involve the control and management of feral swine populations. With federal provisions of feral swine, states might be able to coordinate efforts with neighboring states and would be more likely to adopt additional provisions to control this invasive species.

Contrasts with Australia

The absence of federal policy in the United States on the management of feral swine populations may be contrasted with Australia, where official documentation refers to these animals as “feral pigs” (Commonwealth of Australia 2006). The Australian policy recognized that the animals may be “an agricultural pest, an environmental pest, an animal of cultural value, a food resource, a commercial resource, an endemic and exotic disease hazard and a recreational hunting resource” (Commonwealth of Australia 2006). A report from New Zealand noted an entrenched conflict between persons viewing feral swine as a resource and those who wanted to manage populations (New Zealand Ministerial Panel 2008). This documentation suggests that issues confronting the United States in addressing feral swine are similar in other parts of the world.

However, the federal government of Australia has been more proactive in developing a federal strategy. Section 270B of the federal Environment Protection and Biodiversity Conservation Act 1999 delineates “threat abatement plans” for “feral pigs” (Commonwealth of Australia 2006). The Australian government set out “a national framework to guide coordinated actions to contain the spread of” feral swine and other species. Eradication was recognized as impossible for most areas, so that management controls to control damages was the major objective.

In the United States, the federal government has commenced some efforts to develop a national policy on feral swine. In May, the USDA published a notice of intent to prepare an Environmental Impact Statement on a feral swine damage management program and notice of public meeting (USDA 2013b). This was followed by a public hearing at which various federal officials from the USDA, Wildlife Services, and Veterinary Services presented ideas on the development of a federal program. It was acknowledged that “interstate laws regarding the illegal movements of feral swine needs [sic] to be in place,” yet feral swine cannot be listed as injurious wildlife due to the absence of authority to regulate subspecies (USDA 2013c, pp. 60–61, 85). This suggests that the US wildlife law precludes the US from taking action similar to Australia’s “threat abatement plans.”

The Australian national government has also proceeded to delineate a “Model Code of Practice for Controlling Feral Pigs” (Sharp and Saunders 2012). The code is to help persons choose humane, cost-effective, and efficacious techniques for reducing the negative impacts of feral swine. The US might consider adopting analogous provisions to establish management policies that facilitate reductions of feral swine populations while complying with legal constraints and humanely treating animals being eliminated.

The Environmental Impact Statement being prepared by the USDA (2013b) may enable the US government to justify the need to control and manage feral swine populations. It will presumably contain scientific information on disease threats posed by feral swine, which would facilitate the development of a national disease control program and new federal regulations. As noted by the Center for Food Security and Public Health at Iowa State University (2009), brucella abortus has been found in a feral swine population and concern exists that it might be transmitted to domesticated livestock. It is appropriate for the US federal government to address the risks of feral swine spreading diseases to domestic animals and wildlife.

Returning to the Australian model code, its federal provisions do not replace legislation that applies under state and territorial jurisdiction (Sharp and Saunders 2012). At the state level, Queensland has imposed an obligation on landowners to keep their land free of certain pests including feral swine (Queensland Department of Agriculture, Fisheries and Forestry 2013; Queensland Parliamentary Council 2013). This shows a strong government action to control invasive species. If the US government develops federal regulations, then they would undoubtedly allow states to continue with more specialized management and eradication efforts. However, a strong property rights ethic in the US means that an obligation such as imposed by the government of Queensland is unacceptable.

The Australian government has also released reports on trapping, aerial shooting, ground shooting, use of Judas pigs, poisoning, and euthanasia for guidance in the management and control of feral swine (Sharp 2012a, b, c, d, e, 2013). These national reports delineate practices for individuals to follow in eliminating animals and prominently delineate animal welfare considerations. Considered together, the reports provide the public with extensive information on controlling and managing feral swine populations. They suggest that Australia has a coordinated approach to addressing controversies involving feral swine. In the US, state agencies have consulted with agencies in other states (Wildlife Society 2012), and individualized state reports provide information for the public (Mapston 2004; Hamrick et al. 2011; Kammermeyer et al. 2011; Higginbotham 2013). However, the US lacks a coordinated federal approach grounded on economics, ecological, and public health policies. This detracts from meaningful controls for this invasive species.

Concluding Comments

In the absence of a US policy on feral swine, most of the issues about feral swine are handled by state governments. While most US state governments have acknowledged the problems associated with feral swine, they have not adopted meaningful provisions to reduce populations. The failed efforts in Texas suggest that more drastic actions are needed. Despite decades of elimination efforts, the state has not been successful in meaningfully reducing its feral swine population (Dart 2013). The lack of credible state legislative responses to expanding feral swine populations suggests that there is a communications problem with convincing people and legislators that feral swine populations are detracting from the state’s economy and pose public health risks. Improving communications by scientists and researchers on damages from feral swine might help policymakers arrive at more appropriate policies (Heger et al. 2013). Agricultural interest groups may need to become more adept at publicizing damages to crops and advancing acceptable practices for reducing numbers. Greater public support is needed to convince legislators to take additional actions to reduce population numbers.

Due to a number of reasons, some states are unlikely to adopt provisions that would result in meaningful reductions of feral swine populations. Given the large areas and different topographies of the US states, groups desiring to reduce populations might advance a proposal under which the state legislature would grant more powers to counties. Granting counties more authority to address feral hog populations could lead to controls made by elected officials closest to landowners being affected that are consistent with cultural and social beliefs of an area. County ordinance provisions would allow citizens in communities being adversely affected to take actions to assuage damages to crops, wildlife, and ecosystems. A variety of techniques may be needed, including hunting, preclusion, outlawing possession, trapping, toxicants, and fertility control agents (Campbell et al. 2006).

Simultaneously, the US federal government should become more involved in responding to significant crop and natural resource damages being inflicted by feral swine and the risk they pose to domestic livestock. Policies in Australia offer some ideas for a coordinated federal approach. However, given the impediments imposed by the US federal law, the most fruitful federal action would be to develop a disease management program. As a preventive action to protect the health of farm animals, this program could establish proscriptions that would operate to reduce feral swine populations and preclude the introduction of animals to new areas. Federal controls to safeguard health of domestic animals would supplement controls enacted by the US state and local governments.

In a democracy, elected legislators enact laws to protect citizens from damages including those from invasive species. While governmental officials have responsibilities to all citizens, they should strive to regulate activities that detract from the wellbeing of a majority. Because feral swine populations are destroying crops and ecosystems to the detriment of the economy in many locales in the United States and pose health risks to other animals and humans, legislators and governmental officials who fail to respond in a meaningful way are remiss in their responsibilities.

Biographies

Terence J. Centner

is a professor in the Department of Agricultural and Applied Economics.

Rebecca M. Shuman

is a graduate student at The University of Georgia, Athens.