A Sounder Approach to Feral Hog Control

By Matt Hill and Mark McLain | September 1, 2016
From Missouri Conservationist: September 2016

Missouri has an abundance of natural resources including our beautiful Ozark forests, clear springs and streams, glades, prairies, rich crop ground, and healthy wildlife populations.

Unfortunately, some of the resources that make Missouri great are being destroyed by a terrible invasive species feral hogs.

How a Few Released Hogs Became a Big Problem for Wildlife and Farms

Feral hogs became a problem in Missouri around the late 1990s when a few misguided sportsmen illegally released hogs for the purpose of establishing populations for hunting. With continued illegal releases and natural reproduction, feral hog populations boomed across the southern Ozarks, and now this destructive invasive species is in more than 30 Missouri counties. Feral hogs are bad in many ways. They destroy wildlife habitat and natural communities such as fens, glades, wetlands, and bottomland hardwood forests by rooting and wallowing the ground. They also eat ground-nesting birds and other wildlife, and they outcompete native wildlife for food.

They can contaminate streams and rivers, and they can carry many diseases including pseudorabies and brucellosis that can be transmitted to livestock, pets, and people.

Recently Dr. Jason Weirich, director of Agronomy for MFA Incorporated, commented on the threat feral hogs pose to Missouri farmers. “Feral hogs are a great concern to agriculture due to their ability to destroy crops and pasture. In fact, a group of 10-12 hogs can destroy 10-20 acres overnight. That sort of damage not only destroys good farmland, but hurts the pocketbook as well.” Don Nikodim, executive director of the Missouri Pork Association agreed. “Feral hogs pose a serious threat to Missouri’s pork industry because of their potential to spread disease. The reintroduction of swine brucellosis or pseudorabies from feral hogs would be disastrous. Feral hogs need to be eliminated from our state.”

After trying numerous methods to control them, managers found trapping to be the most effective way to eradicate feral hogs. In 2012, the Department organized its efforts and cooperated with partner agencies (the U.S. Department of Agriculture, Animal and Plant Health Inspection Services-Wildlife Services, government agencies, agricultural groups, nongovernmental organizations, and hundreds of private landowners) to develop and implement a feral hog eradication plan. The group of partners also mounted an aggressive education campaign to inform the public of the destruction feral hogs cause and how they threaten Missouri’s fish, forests, and wildlife. The coordinated effort among all the partners and landowners has made great strides in this fight.

Hog Trapping Successes

When the Missouri Department of Conservation and partners first started trapping hogs, they preferred the corral trap equipped with a rooter gate, a small 3-by- 3-foot trap door that closes behind the hogs after they enter and hit the tripwire at the back of the corral. This effective trap captured thousands of hogs over the years.

But feral hogs are sensitive to any disturbance, and they can become shy to the rooter gate’s small opening. To build a better hog trap, the U.S. Department of Agriculture, Animal and Plant Health Inspection Services-Wildlife Services (USDA-WS) developed the Missouri Drop Gate. This trap’s door has an opening that measures 6 feet wide and 3½ feet tall. The door drops down from a raised and locked position like a guillotine once the hogs hit the trip wire. Because the opening is much wider than the original rooter gate, the drop gate captures more hogs from one group with fewer trap nights, making eradication efforts more efficient. Along with the new drop gates, the corrals are larger. The corral is made up of 16-foot-long welded wire panels fastened to posts that are driven into the ground to keep it in place.

The larger corral allows more hogs to get into the trap at once, and with the extra room the hogs seem to go into the trap sooner. The drop gates on large corrals are working very well. In 2015, the Department and its feral hog partners removed 3,649 feral hogs from the state.

Building a Better Hog Trap

The Department is constantly learning new eradication techniques and continues to develop and implement new and better equipment. The latest innovation in hog traps is the drop or suspended trap. Drop traps are enclosures that are fully suspended by a minimal support structure on the ground so that the hogs do not notice the trap is above them. Because there are no trap doors or panels on the ground to restrict their movement, the hogs often will all go under the drop trap the first night it is set. The idea of the suspended trap came to Missouri from the researchers at the Samuel Roberts Noble Foundation (the Foundation), an independent, nonprofit institute headquartered in Ardmore, Oklahoma. They develop new trap designs to assist farmers with feral hog problems and conduct research to enhance agricultural productivity regionally, nationally, and internationally.

The drop net was the first trap design the Departmentused from the Foundation. It is a net 60 feet wide and 60 feet long that is suspended by five support poles and a series of ropes and pulleys. All of the ropes come back to a central release mechanism that is triggered by an electronic remote control. All of the drop net components can be hauled to the trap site in the back of a truck or on a small trailer pulled by an ATV and be set up, ready to trap in a short time. Once the net is dropped, the hogs quickly get tangled tightly in the netting and cannot escape. Trappers then rush in and dispatch the hogs.

The Foundation’s most recent innovation is The BoarBuster™. This is a round trap made of rigid corral panels that are supported by three legs. It comes with a camera that operates much like a basic trail camera except it is connected to a cellular network, which allows the trapper to monitor the site and trigger the trap remotely from a computer or portable electronic device. When the camera detects motion, it automatically sends a text message or email to the trapper to alert them that something is at the bait site. The trapper can then log into the website to view the picture. If feral hogs are present, the trapper can turn on the live video feed. This real-time surveillance is critical to determine if all of the hogs in that sounder (family group) are under the trap so trappers can determine the best moment to drop the trap. Once the entire sounder is under the trap, the trapper clicks a button on the screen that drops the trap around the hogs. These drop-style traps have proven to be the most efficient and effective feral hog eradication tool used to date.

Selective Shooting Works Better Than Shooting on Sight

The Department still employs other specialized eradication methods, such as aerial gunning and targeted night shooting to eliminate hogs in rough, remote areas or to remove a single hog in an isolated spot. These methods are invaluable to eradication efforts. The helicopter can get to areas with no roads or to a wilderness area where motorized vehicles are restricted. Targeted night shooting helps eliminate a single roaming hog or the last few hogs from a sounder, allowing trappers to move on to another group of hogs in a different area and systematically eradicate them.

Feral hogs maintain a home range in which they travel, forage for food, and reproduce. This is one of their weaknesses and, if left undisturbed, they stay close to their home range. A typical feral hog sounder in Missouri has a home range of about 1,000 acres. When trapping, the Department tries to identify these home ranges and find the best spot in that range to catch the entire group at once. This is why, many times, traps are not placed at every location that has hogs. If hogs are using four different properties, but are spending most of their time on one particular property, that is where a trap is set. The best chance of catching the entire sounder is on the property where the hogs are spending the most time. This strategic approach allows staff to set up traps on many different sounders of hogs across the landscape. Such an approach ultimately removes more hogs, bringing the goal of eradication closer. In these situations, neighboring landowners should work together, baiting and running the trap.

A Unified Front Against a Common Enemy

Early in the fight against hogs, the Department realized it was fighting a war, not a battle, and that eradicating hogs from Missouri would take a cooperative effort. The Department continues to enlist the cooperation of many additional landowners each year. The USDA-WS has been an instrumental partner from the beginning of these efforts in Missouri. They currently have five full-time hog trappers in Missouri that provide trapping assistance, knowledge, experience, innovative trap designs, and materials for trapping. The Department also coordinates aerial gunning of hogs with USDA-WS helicopters from Oklahoma and Tennessee. The Department recently partnered with a wide range of groups, including agricultural and conservation groups and the Missouri Conservation Heritage Foundation. All these partners are committed to eradicating hogs from Missouri and provide funds and public support for the common goal.

Call or Click, But Please Don’t Shoot

Missouri has learned from other states and, by trying different methods, that trapping is the most effective way to eradicate feral hogs. Hunters shooting feral hogs complicate efforts to remove these pests by scattering sounders and disturbing trap sites. If you encounter a feral hog, please call the number or visit the website on the opposite page to report it as soon as possible. If you are experiencing feral hog damage on your property, find trapping assistance by contacting the phone number or visiting the website. With your help, we can eliminate this dangerous and destructive invasive species from Missouri.

Approved Feral Livestock Regulations

In January 2016, the Department proposed new regulations that would prohibit taking feral livestock on any property owned, leased, or managed by the Department. This regulation was approved by the Conservation Commission and will become effective on Sept. 30, 2016. It will allow the Department to trap feral hogs on lands it owns, leases, and manages without disruption from hog hunting.

Tennessee: Lessons Learned

For many years, Tennessee had two small feral hog populations in 15 counties on the eastern side of the state. For 50 years they did not allow hog hunting, and those populations remained only in those 15 counties. In 1999, the state chose to open a hunting season on feral hogs. Now Tennessee has hog populations in nearly 80 counties across the state. Hunting made their hog problem worse and the goal of eradication much more difficult. Tennessee officials have since eliminated hog hunting and are now working to eradicate feral hogs from their state.

Also In This Issue

Rabbit Hunting
Non-hunters take to the woods well into adulthood
Agent and Girl Fishing
Missouri’s conservation agents are out in communities protecting and conserving our fish, forests, and wildlife... and building relationships along the way

This Issue's Staff

Editor - Angie Daly Morfeld
Art Director - Cliff White
Associate Editor - Bonnie Chasteen
Staff Writer - Heather Feeler
Staff Writer - Kristie Hilgedick
Staff Writer - Joe Jerek
Photographer - Noppadol Paothong
Photographer - David Stonner
Designer - Les Fortenberry
Designer - Marci Porter
Designer - Stephanie Thurber
Circulation - Laura Scheuler