The outcome of Missouri's war against feral hogs remains uncertain, but conservation officials are gathering intelligence behind enemy lines and marshalling forces for a pitched battle.
Missouri currently is in the early stages of a feral-hog population boom. Swine ranging from domestic porkers to hog-wild descendents of razorbacks and Russian boars exist as established populations in 20 counties, mostly in southern Missouri. Another 19 areas scattered all over Missouri have isolated feral-hog populations.
In almost every case, these populations grew from animals released deliberately to create hunting opportunities.
Unfortunately, those opportunities come with serious liabilities.
Rex Martensen, who is in charge of the Missouri Department of Conservation's feral-hog control effort, says hogs running loose create ecological havoc, taking acorns and other natural foods away from wildlife They root up large expanses of forest and field in search of roots, bulbs, small mammals and the eggs of ground-nesting birds, including quail and turkeys. They also invade crop fields and pastures. Crops planted as food plots on conservation areas are favorite targets of wild hogs.
As if that were not enough, feral hogs seek out springs, seeps and fens where they wallow, creating erosion and fouling streams with their feces.
Most feral hogs weigh less than 200 pounds, but they can grow to more than 500 pounds. Regardless of size, sharp tusks and an aggressive disposition make feral hogs dangerous.
Feral hogs also pose an economic threat to Missouri. In 1992, the Missouri Department of Agriculture (MDA) imposed quarantine on several thousand acres in Carter, Shannon, Oregon and Ripley counties after feral hogs in the area were found to have pseudorabies. Wild hogs can carry the pseudorabies virus without serious symptoms, but the disease is fatal to many other wild and domestic animals.
Missouri's domestic swine are considered disease free and a good source for safe, healthy pork products.
However an outbreak of swine brucellosis or pseudorabies from feral hogs into domestic swine could severely cripple Missouri's pork industry, creating a negative economic impact that would affect the entire state.
Besides pseudorabies, feral hogs can carry leptospirosis, swine brucellosis, swine fever, foot-and-mouth disease, African swine fever and several other potentially devastating diseases. A federal quarantine to prevent the spread of such diseases would be enormously damaging to Missouri agribusiness.
Swine brucellosis can infect humans, causing a malady known as undulant fever.
This can cause arthritis, urinary inflammation, meningitis, heart inflammation and depression.
The Conservation Department has opened two fronts in its war on feral hogs. One is in Iron, Reynolds and Wayne counties -- the epicenter of a large infestation in the Ozarks.
This area encompasses thousands of acres of state and federal land and some of the state's most fragile ecosystems -- glades and fens. The other area is public land in west-central Missouri.
Since Jan. 1, Conservation Department workers have removed more than 200 hogs from conservation areas or surrounding private property where landowners have asked for help.
Efforts by the U.S. Army Corps of Engineers and the U.S. Department of Agriculture's Animal and Plant Health Inspection Service (APHIS) bring Missouri's 2009 hog-removal total to nearly 400.
While this is better than nothing, Martensen says much more effective measures are needed. Feral hogs are so prolific they can maintain a stable population with 70-percent annual losses.
"We aren't anywhere near that," said Martensen. "At present, we are only slowing the growth of the feral hog problem, not stopping it. Our goal is to eradicate hogs from state land. However, we would still consider it a success if we eliminated them from some areas and contained their spread in others."
So far this year, the two most effective hog-removal methods have been aerial gunning from a helicopter and catching hogs in corral-type traps with one-way doors. Other methods, including snaring and sharpshooting with night-vision equipment, are less effective, but still valuable for removing remnant hog populations following trapping and aerial shooting work.
The Conservation Department continues to develop new techniques and strategies for hog removal. One technique that has not panned out as well as hoped is the use of Judas pigs. This is intended to take advantage of hogs' social nature. A trapped hog is fitted with a radio-tracking collar and released. In theory, hog eradication crews should be able to follow the collared pig back to its herd. However, the success of this method has been limited at best.
Spying plays a role in every war, and the Conservation Department's hog hostilities are no exception. Trail cameras are a valuable tool in anti-swine espionage. These cameras have become popular with deer hunters in recent years. Triggered by motion or infrared sensors, they take digital photos or videos of passing wildlife 24 hours a day.
An even more sophisticated way of gathering intelligence behind enemy lines involves unwitting informants. The Conservation Department fits captured hogs with GPS (global positioning system) collars that record the animal's position every 2.5 hours.
Martensen calls the current strategy of each agency pursuing feral hog eradication on its own land a "shotgun approach." He said the multi-agency Feral Hog Task Force created by Gov. Blunt in 2007 is discussing a concerted effort in a selected area to see what they can accomplish by focusing all their resources in a limited area. This is a good fit for the current stage of Missouri's feral-hog problem, which still consists of isolated populations that could be eradicated one by one.
"If it works, then we apply those methods to other areas of the state," said Martensen. "If it doesn't work, then we identify why it doesn't work and see if we can fix it and take another run at it."
The Conservation Department has budgeted $45,000 this fiscal year for the feral-hog fight.