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Posted Dec. 26, 2012

As agricultural producers grapple with the costly damage of feral hogs, two Noble Research Institute researchers provide a revolutionary solution
clay forst
Clay Forst of Caddo, Okla., shows damage to his food plots caused by the rooting of feral hogs.

"What has taken me two years to grow, hogs destroyed a quarter of it within two nights."

Clay Forst

  • Photos

On an unusually warm fall morning, Clay Forst carefully navigates his white Tahoe through rocky terrain down into a series of interconnecting pecan bottoms on Boggy Creek. Forst, who manages the wildlife outfitting division of his family's 13,000-acre ranch near Caddo, Okla., would enjoy this morning ride except he's preparing to show a pair of visitors something that truly frustrates him. Deep, sporadic holes scar a lush, green, turnip-filled food plot; clear evidence of feral hogs looking for food in the night.

As Forst continues touring the ranch, he spots a small, tripod deer feeder, frowns and moves to investigate. For weeks, Forst has been battling the hogs to keep this feeder upright. He would fix it; they would tip it back over and gorge on the golden corn within. He'd fix it again, fastening it with wire; they'd wrangle it loose again.

"Lots of hard work and money go into planting food plots, as well as repairing what the hogs tear up," Forst said. "It's depressing at times to see all the money and work destroyed overnight."

Farmers and ranchers have cursed (and, in a few rare cases, enjoyed) feral hogs for decades. Once managed as free range livestock, feral hog populations are spreading throughout the United States. As this hog population expands, agricultural producers and landowners grapple with the reality of controlling these ever-present pests. Just ask Forst.

A Hog History
Simply put, feral hogs are an invasive species in the U.S. Early explorers, such as Hernando Cortes and Hernando de Soto, brought domesticated swine with them on their global explorations, managing them as free range livestock. Many of the swine simply wandered off and became feral (i.e., an animal that has changed from domesticated to being wild or untamed), which led to the rise of hunting the hogs.

Feral hog populations continued to grow through the decades and embrace a larger footprint. Feral hogs now exist in approximately 38 of the 50 states with California, Florida and Texas possessing the heaviest populations. (Oklahoma's population is considered healthy and growing.)

Feral hogs' success can be attributed to several factors, including the animal's ability to adapt to a variety of situations, eat a variety of foods and reproduce rapidly.

"They are prolific reproducers," said Russell Stevens, Noble Research Institute wildlife and range consultant. "However, there is a lot of misinformation about how many piglets they can have. Feral hogs are capable of producing two litters per year (but rarely do) with each litter consisting of four to 10 piglets. Good habitat, nutrition and weather allow production of the most young, with peak numbers usually born in late winter or early spring."

Despite their prolific breeding and expansive range, the exact number of feral hogs remains difficult to accurately measure.

"Historically, there has never been an accurate report of feral hog numbers or their distribution in Oklahoma," Stevens said. "Their secretive nature makes it difficult to obtain. Statewide distribution is easier to estimate, but is mostly limited to knowledge of their presence or absence in a particular county."

During the summer of 2007, Noble Research Institute wildlife and fisheries staff initiated a statewide survey to obtain a better estimate of the distribution and number of feral hogs in Oklahoma.

Representatives of the surveyed agencies were contacted in every Oklahoma county and asked if feral hogs were present in the county and to estimate the density.

Based on the respondent estimates, the feral hog population in Oklahoma was between 617,000 and 1.4 million. With inherent mapping error taken into account, the estimated feral hog population in Oklahoma was calculated to be about 500,000. Estimates nationwide range from 4 million to 5 million feral hogs.

"Feral hogs can adapt to any plant community," Stevens said, "but they prefer moist bottomlands or riparian areas associated with streams and rivers."

The hogs' penchant for following riverbeds explains part of their expansion. As water development has spread into more arid regions, along with improved range conditions through better livestock grazing practices, the hogs have followed the availability of land and food.

"We have had a hog problem for a few years," Forst said. "However, when Boggy Creek flooded a couple of years ago, the hog numbers increased and so did the damage."

The costly case against feral hogs
Feral hogs, like all animals, are susceptible to many infectious and parasitic diseases, but cause more problems through rooting, wallowing and destruction.

As an introduced species, feral hogs compete with native wildlife and domestic livestock, consuming large amounts of mast production like acorns and pecans that wildlife species depend on for winter survival, and consuming and damaging forages necessary to livestock.

"For example, most producers in southern Oklahoma and northern Texas use bermudagrass as the main forage for cattle," Stevens said. "However, bermudagrass seems to be one of the favorite food items for feral hogs in the winter. Hogs rooting up the bermudagrass decrease the production potential for that field the following spring and summer."

Harm to crops and farming can be very costly to producers in Oklahoma and Texas. The most extensive crop damage usually occurs at planting time or when a crop is nearly mature. Rooting also causes physical damage to the property by creating holes and a rough surface for planting and harvesting equipment.

In Texas, it is estimated that one hog can cause about $200 in agricultural crop damage each year. If one multiplies $200 by the average size of a sounder - about 20 animals - then producers face significant losses.

"A small 1.5-acre food plot isn't much, but it cost me $95 an acre to plant," Forst said. "Within two nights, hogs destroyed a quarter of what has taken me a year to grow."

Feral hogs can also cause costly damage to landscaped areas such as golf courses or other public facilities that may be near areas that have populations of hogs. "We have photo documentation of hogs on the Noble Research Institute's campus, rooting through the lawn and flower beds," Stevens said. "That's not too expensive to replace, but you get into golf courses and costs skyrocket."

Besides damage to the land, feral hogs also hurt water resources and quality for wildlife and livestock consumption. Small water sources, such as streams and creeks, sustain the most damage through the hogs rooting and wallowing.

The actual effect of feral hogs on the environment is largely unknown, but it doesn't matter to Forst. He wants them gone. "There needs to be a collective push to trap, hunt and harvest feral hogs," he said. "They will overrun the land and destroy a lot of acres, and a lot of money will be spent to control them after the damage has been done."

Many people experiencing problems with feral hogs are, like Forst, eager to eliminate them, but extermination is difficult. Feral hogs are adaptable and tenacious when it comes to survival.

No easy solution
Although total and permanent removal is unlikely, trapping is currently the best method for controlling hog numbers.

"Controlling hogs using trapping isn't a one-time job and you're done," said Ken Gee, Noble Research Institute senior wildlife researcher. "Due to their mobility and high reproduction rate, you have to monitor hog populations and implement control techniques periodically."

Cage and corral-type traps are the most prevalent trap designs because they are relatively inexpensive and somewhat portable.

Unfortunately, sometimes the feral hogs become trap-shy. "They are smart animals." Gee said. "Feral hogs can become educated and become wary of traditional, corral-type traps,"

Feral hogs can be hunted throughout the year. Traditional hunting is generally ineffective for controlling hog numbers, according to Gee. Another method of population control is the "Judas pig" tracking technique. This technique was signed into law as Senate Bill 1751 and became effective Nov. 1, 2012. The law allows landowners and hunters to use an electronic tracking device to monitor this pig until it joins the sounder (group of feral hogs), revealing the position or pattern so the sounder can all be removed.

For most, however, trapping is the answer. But how do you best trap feral hogs?

The Noble Research Institute began research on feral hogs in 2010. Gee, along with Josh Gaskamp, Noble Research Institute wildlife research assistant, conducted a two-year research study to measure the effectiveness of drop nets versus corral traps in capturing feral hogs.

"Numerous trap designs have been used to capture hogs," Gee said. "However, drop nets have never been examined as a potential tool for feral hog control. In the mid-1990s, we began using drop nets to capture feral hogs that were interfering with our white-tailed deer capture efforts. The technique was successful enough to warrant further exploration."

A two-year study was implemented to compare the effectiveness and efficiency of a 60-foot by 60-foot drop net, which is completely suspended, eliminating near-ground visual obstructions, versus a traditional corral trap where pigs enter a cage structure and a door closes behind them when a trip wire is activated.

In 2010 and 2011, multiple trap sites were identified on 10,000 acres in Love County, Okla. Trap sites were baited with whole corn and monitored with infrared-triggered cameras. The study, which removed 356 hogs between the two methods, showed that the drop nets were more effective than corral traps.

"We captured a larger portion of the population with drop nets, often capturing the entire sounder," Gaskamp said. "The hogs were not hesitant to walk under the drop nets because there isn't a structure at ground level."

Capturing an entire sounder reduces instances of hogs becoming educated to the inner workings of the trap, Gaskamp said. Additionally, non-target captures, such as deer, raccoons and turkey, are eliminated because humans, not the animal, trigger the drop net. To some landowners, this is an inconvenience. They prefer capture techniques that do not require observation time in the field, especially since hogs are often active throughout the night.

While effective, a drawback of drop nets is that it is difficult to get the hogs out of the net without euthanizing them.

After the first year of the study, Gee and Gaskamp began to see that combining the best of both traps might lead to the most effective and efficient trap. "We needed the unobtrusiveness of the drop nets," Gee said. "And the convenience and accessibility of the corral traps."

Necessity became the mother of invention. Now they just had to design and build it.

The birth of the BoarBuster
Gaskamp and Gee developed the BoarBuster, a fully suspended, remotely activated, selective corral trap made out of cattle panels. "The BoarBuster is basically a corral trap that we are able to suspend, and then monitor and drop from a remote location," Gaskamp said. "All visual obstructions are eliminated so the hogs don't become trap-shy."

The new system allows the wildlife team to be offsite during the drop. In fact, Gaskamp can drop the trap anywhere he can get cell phone reception. The new BoarBuster system will send Gaskamp an email or text message to alert him that there is motion at a trapping location.

Using cameras set up at each site, Gaskamp can watch the animal(s) through his smartphone or personal computer (eliminating any unwanted animals from being trapped) and then remotely spring the trap whenever the expected number of hogs has entered the trap.

"I can be at home watching TV or at a ballgame, receive a message, watch the sounder gather and then spring the trap," Gaskamp said. "I can then leave the hogs in the trap and go collect them the next day."

Building and field testing the trap soon sparked another study. Gee and Gaskamp wanted to compare the efficiency and effectiveness of the BoarBuster to the two previously studied methods. This study is currently in progress, but initial results are positive.

The catch per unit effort for the BoarBuster was roughly 300 percent greater than drop nets and corral traps, and the trap has snagged a maximum of 39 hogs in a single trapping event. "About 88 percent of the identifiable hog population is being removed using the BoarBuster, which is similar to drop net effectiveness," Gaskamp said. "However, unlike drop nets, the BoarBuster's remote operation saves time by eliminating the need to observe them from the field. A load-out door allows us to remove animals with ease."

Word about BoarBuster is out and desperate landowners want the new trap. The Noble Research Institute is currently working to license the BoarBuster patent to a manufacturer/distributor. "We have also received calls from state and government wildlife agencies that want to implement this trap into their control programs," Gaskamp said. "The new trap has potential to be a game changer for localized feral hog control."

For agricultural producers like Forst, "control" would be a welcome relief. Until then, he'll be out fixing his deer feeder.