by Mayzie Purviance
An invasive species, as defined by the National Park Service, is a “non-native organism whose introduction causes or is likely to cause economic or environmental harm, or harm to human, animal, or plant health.” Feral swine could easily fit any of those descriptors.
Feral swine, often referred to as wild pigs or wild hogs, may not be a pressing issue in the northwestern U.S. – yet. But populations are running rampant in southern states and Canada.
“The northwestern states should be paying close attention as to what has happened in the southeastern United States and take steps to prevent intentional introductions,” Billy Higginbotham, expert on feral swine and Professor Emeritus-The Texas A&M University System, said.
Higginbotham explained that growth and expansion of the feral swine population happened rapidly. In 1982, Animal and Plant Health Inspection Service (APHIS) released a color-coded map highlighting counties infiltrated by feral swine in blue. Twenty states on the map included “blue” counties. Of the 30 uninhabited states, all were northern.
The same APHIS graphic in 2018 had far more “blue,” with every state south of Tennessee and east of Texas completely colored, with the exception of a few urban counties. California had all but one county inhabited by feral swine while states such Kentucky, Nevada and Arizona resembled a speckled robin’s egg. The 2018 APHIS Feral Swine Distribution Map reported 35 states invaded by feral swine. Among these states were more northern states including Michigan, North Dakota, Washington and Oregon.
Along with these 35 states in the U.S., Higginbotham said all provinces in southern Canada, with the exception of those along the Atlantic coast, have wild pigs in their range. These feral swine are expanding at an increasing rate of 55,000 square miles per year.
Efforts are actively being made in regard to feral swine control and eradication. USDA recently announced they are allotting $75 million to the Feral Swine Eradication and Control Pilot Program (FSCP). A pilot program of the 2018 Farm Bill, this cash influx to the FSCP was provided in a joint effort by the USDA’s Natural Resources Conservation Service (NRCS) and APHIS.
“The eradication/control program has brought the issue of wild pigs to the national level and any additional federal funding is a step in the right direction on what I call ‘The War on Wild Pigs,’” Higginbotham said.
Dr. Susan Keller, DVM, North Dakota State Veterinarian, said wild pigs haven’t taken over North Dakota like they have in some states.
“There are states that have feral swine populations which are out of control and USDA understands the damage to agriculture and agricultural land that feral swine cause, as well as the risk they are to the movement of diseases which impact swine and other animals as well,” Dr. Keller said. “It will take not only funds, but also a change (in some cases) as to how feral swine are addressed in state regulations in order to try to eradicate them. Eradication has to be the goal, because assuming that the population can be controlled has proven to be challenging, if not impossible.”
Keller said in 2008 the North Dakota Board of Animal Health issued a standing order to have confirmed feral swine reported either to the state veterinarian’s office, to a local North Dakota Game and Fish warden or USDA Wildlife Services. Local authorities and local county agents are to be contacted and asked to help determine if the pigs are domestic. If they are unclaimed, they are classified feral swine and are to be destroyed by Wildlife Services and samples are to be collected for disease testing.
Although this is protocol in North Dakota, not every state uses such guidelines. In 2018, APHIS reported trapping, aerial operations and recreational hunting of feral swine have effectively reduced damage in some areas. But at least 70 percent of feral swine must be removed each year in order to prevent population growth. With the U.S. being home to 6 million feral swine who cause an estimated $190 million worth of damage to agricultural crops alone, some believe toxicants must be legally introduced.
“Toxicant testing has been on-going for several years using a product with the active ingredient sodium nitrite and field-testing trials are ongoing,” Higginbotham said. “Attempts to legalize a toxicant containing warfarin were not approved a few years ago.”
Sodium nitrite is a chemical commonly used as a meat preservative to cure meats such as sausage and bacon. Sodium nitrite is toxic to feral swine when consumed in high doses over a short period of time. Although allowing producers to legally use sodium nitrite will help tremendously, Higginbotham said the approval of a toxicant alone will not mean the eradication of all wild pigs in the U.S.
The Future of Feral Swine…
Although feral swine populations aren’t out of hand in the northwest U.S. to date, they could be should proper population control measures not be taken. While southern states urge the passage of legal toxicants, northwest states still have the opportunity to set successful control tactics before populations become established. Higginbotham, whom witnesses feral swine destruction each day, issued a “warning” for those in the northwest to not give in to the glorification of hog hunting and strongly discouraged stocking of feral swine for hunting and dogging purposes.
With rapid expansion across the U.S. and southern Canada of feral swine in the past 36 years, it is expected that more and more northwestern states will see a population increase in wild pigs. But between the already successful protocols and the initiative of the FSCP, feral swine could stay unproblematic in the northwest.
“I am grateful that the swine industry in North Dakota advocated for and helped develop a protocol to address feral swine concerns back in 2008,” Dr. Keller said. “Due to neighboring land within the state and neighboring states that the Board does not have jurisdiction over, it is expected that there will continue to be occasional sightings of feral swine that we will continue to investigate and address as soon as reported.”BACK