Unfortunately for deer hunters, there is only a certain time of the year that they are able to pursue their passion … white-tailed deer. Depending on the state, the season is normally a three- to four-month period considering all of the days that can be legally hunted, but most hunters typically don’t hunt all of the season because they don’t hunt with all weaponry, or they have limited ability to break away from obligations associated with family and/or work.
For gun hunters, the most common type of deer hunter, the season might be as short as nine days. I began hunting with a 16-day gun season, and I did everything I could to break away from my obligations at school during those short windows of opportunity. Usually, this meant I could hunt somewhere from five to seven days during the season … far fewer than I would have been able to hunt if deer hunting was legal throughout the year. So, outside of those few days I could hunt deer, I would read about hunting, watch hunting shows and daydream about mature bucks. Deer season for me was the same as Christmas for a 7-year-old … it came once a year, and was gone before I knew it. So what’s a deer hunter to do?
One rapidly growing pastime for deer hunters that enables them to get into the woods throughout the year and hunt large game is wild hog hunting. Wild pigs are very similar in size to deer, they provide meat for the freezer, and there are generally no season or bag limits for these animals. They make the perfect quarry to pursue during spring or summer for a deer hunter experiencing withdrawal.
Although wild pigs aren’t found everywhere, their range has rapidly spread over the past 25 years, and at one time or another have been found in 47 of the 50 states. They are found in large numbers across the Southeast from Texas to North Carolina, in California and Hawaii, and there are spotty populations developing in the Midwest and other areas of the country. At the current rate of spread, every deer hunter in the country is soon going to be able to scratch their “big game itch” all year long.
What are Wild Pigs?
Wild pigs are descendants of a combination of released, pure-blood Eurasian wild boars and wild descendants of domestic swine (most domestic swine were selectively bred from Eurasian wild boars). They are not native to North America, but were first introduced by early explorers who released them in areas they planned to revisit in the future. Domestic swine have always had an incredible ability to survive and reproduce in the wild, and so these explorers would have a ready supply of fresh meat that they were familiar with when they returned on later voyages. These first introductions, along with early laws that allowed domestic pigs to be raised free-range, served as the foundation upon which the current population grew.
Because wild pigs are primarily descendants of domestic stock, they have an astounding rate of reproduction. Domestic pigs have been selectively bred to maximize reproduction, and these genetics have carried over into wild pigs, resulting in the most prolifically reproductive large mammal on Earth. They are generally sexually mature at 7 months, and our research group has found 4-month-old females that were pregnant. They have litters of five to six piglets, often have two litters/year, and can have up to three litters in 14 months if conditions are good. By the time a female pig reaches her second birthday, she might have produced 10 to 15 piglets. In comparison, a female white-tailed deer will generally produce her first fawn (and usually only one) around her second birthday. This all adds up to a huntable animal that we don’t have to worry about over-harvesting. They’ll replace themselves (and more) as fast as we can shoot them. What more could an off-season deer hunter ask for? But wait … it gets better.
As I described previously, the earliest wild pigs in North America were domestics that were released into the wild. Because of their dietary habits, they are able to find food in most habitats, and do well in a multitude of climates, landscape types and ecological regions. They’re omnivorous, and their diet generally consists of 75% to 80% plant material, with the remainder made up of animal matter. Much of the food they consume (roots, tubers, insects, earthworms, fungi, etc.) is rooted up from beneath the soil surface, allowing them to take advantage of a resource that few other animals utilize. So not only do they reproduce quickly, the fact that they are omnivorous and able to utilize food resources that many animals can’t assures that they will be successful in most any area where they are introduced. This is proven by the fact that they have done extremely well in other areas across the globe where they’ve been introduced: Japan, China, Southeast Asia, Africa and Australia.
Too Much of a Good Thing?
On the surface, wild pigs seem like a great addition to the landscape. However, there is a much more sinister side to this animal, and biologists and managers alike consider them to be a major threat to the North American ecosystem. Estimates of damage to agriculture are in excess of $1.5 billion annually, and they’re considered to be the second greatest predator of livestock in some parts of Texas. They carry a multitude of diseases that are a threat to humans (e.g., swine brucellosis, bovine tuberculosis, leptospirosis and others) and are readily transferred by handling wild pig carcasses and bodily fluids. Additionally, they carry numerous diseases that are a major threat to the swine industry and disease-free standards that have been established.
Their proclivity for rooting below the soil surface causes considerable damage to the landscape. It damages sensitive plant communities, increases the rate of spread of invasive plant species, alters nutrient cycling, and the exposed soil caused by their rooting is prone to erosion. Water sources that they frequent usually have considerably elevated levels of sedimentation, nitrates and fecal coliform (E. coli), and disturbances by wild pigs to wetland and riparian systems have been estimated in some areas to be $5,000 to $10,000/acre.
As noted earlier, wild pigs readily consume animal matter, and they can have negative impacts on numerous wildlife species. In one study that our research group conducted at Fort Benning, Georgia, we estimated that wild pigs consume approximately 1,500 reptiles and amphibians per acre each year (960,000/square mile/year). They consume the eggs of ground-nesting birds such as turkeys, quail and pheasants. Preliminary data from a current study that we are conducting for the Alabama Department of Conservation and Natural Resources suggest that the presence of wild pigs may have reduced turkey poult recruitment by 20% to 50%.
We’ve documented wild pigs consuming white-tailed deer fawns, and data from one study we conducted indicated that the presence of wild pigs reduced deer use of baited sites by 50%. While we don’t have data indicating that wild pigs reduce deer density, we do know that they exclude them from some resources, and we hypothesize that they alter movement and behavioral patterns of deer. We are currently conducting a study that is examining the impacts of wild pigs on deer density, social structure and fawn recruitment, and we’ll share the results of the study with the D&DH community when the study is complete.
There is a huge trade-off when you have wild pigs. The benefit is that you can hunt them all year. The cost is all of the damage they do to the landscape, and to the animal and plant communities that are present in that area. Are you willing to accept a reduction in the quality of your deer herd for some pig hunting? How much of a reduction? What about turkeys? Can local agricultural producers sustain a 5%, 10% or even 20% reduction in their profits due to damage from wild pigs? These are the questions we need to be asking ourselves.
What is the Solution?
If you’re of the mindset that wild pigs are not a good thing and that steps need to be taken to reduce the number of wild pigs on the landscape, then you really have only one alternative: trapping. Unfortunately, hunting (stalk hunting, hunting over bait, dog hunting and every other legal form of pig hunting) has been shown time and again to have very little impact on established populations of wild pigs. In areas that have only a few pigs, hunting can sometimes be effective at significantly reducing or eliminating the population. But there is little to no chance that hunting will impact populations that are well established, contrary to what pig hunting enthusiasts claim.
Suffice it to say that wild pigs have too great a rate of reproduction, we don’t hunt often enough and we don’t kill enough pigs as hunters (even when we try). The fact that wild pig numbers have increased historically despite efforts (hunting and trapping) to control them is pretty strong evidence that hunting alone will not be successful. I’m not aware of a single instance where hunting alone has been successful at eliminating an established population or sub-population of wild pigs. But don’t take my word for it, just talk with any wildlife biologist or manager about their efforts to control wild pigs and you’ll hear some horror stories.
While hunting doesn’t show much promise for pig control, trapping has considerable potential to be effective at controlling wild pig populations, if it’s done correctly. Biologists and managers have been trapping wild pigs for decades, and there are a ton of folks out there who are very good trappers. They can remove a lot of pigs in a fairly short period of time, but there are very few success stories when it comes to eradicating populations, even when considerable effort has been applied.
I consider the reason for our poor overall success to be poor strategy. The historical strategy for trapping wild pigs has been to maximize a body count, which would logically seem to be the best strategy. But, in reality, it’s a strategy that is almost guaranteed to fail. In order to maximize the number of pigs that are trapped, you have to move traps frequently and set traps quickly. While this can result in the removal of a lot of pigs, it also ensures that not all of the pigs in an area will be trapped, and that the ones that remain have been educated.
Remember when I said that this is the most intelligent game animal in North America? What remains is an educated, reproducing machine that has just been rid of all of its competition for food resources. They will quickly replace all of their brethren while pig control efforts have been moved to other areas, or terminated due to the incredible “success” of the trapping.
I would argue that rather than a strategy of maximizing a body count, you should have a strategy that ensures that you trap them all. My mantra is: “It doesn’t matter how many you trap, it only matters how many you leave behind.” At first glance this statement might seem redundant, but I think if you keep reading you’ll recognize the underlying strategy in this statement.
In 2008, our research team at Auburn began an experimental wild pig control effort to see if we could successfully eradicate wild pigs from a 20,000-acre area of Fort Benning in Georgia. We hypothesized that if we were aware of every sounder (a sounder is a social group of wild pigs that is composed of related adult females and their young; adult males are solitary and travel from sounder to sounder looking for reproductive opportunities) in the area, and we knew the composition (how many adult females and young) of each sounder, then we could ensure that we successfully removed entire sounder groups and minimized the chance that we did not educate or leave any animals behind. The graduate students working on this project developed a simple five-step process to maximize the probability that this trapping strategy would be effective, which they called “Whole Sounder Removal.”
The Whole Sounder Removal trapping strategy is based upon a couple of key behavioral aspects of wild pigs. First, individual sounders have a tendency to utilize and defend space against other sounders, and thus often have non-overlapping home ranges with other sounders. We learned this through some of our early research on wild pigs at Fort Benning. Second, wild pigs move across the landscape very slowly. As recently as 15 years ago, the general belief was that wild pigs moved across the landscape very quickly and that they showed low site fidelity. The fact that wild pigs have been here for more than 500 years and yet there are still considerable areas in the United States that don’t have pigs is strong evidence that they do not spread quickly on their own. What this means is that if you eradicate wild pigs from an area, it should remain pig-free for some time because there are none left to reproduce and pigs colonize new areas slowly. While the rapid expansion of wild pig populations across the United States during the past 25 years seems to contradict this point, this spread has been caused primarily by intentional and unintentional releases of wild pigs for hunting purposes.
Whole Sounder Removal
STEP No. 1 — Survey the Population: The first step in the Whole Sounder Removal process is to figure out how many groups of pigs are present and where those pigs are located. You can accomplish this by setting up game cameras across the area of interest over a grid of 400 to 500 acres. Because the average home range size of a sounder is 600 to 800 acres, this grid size should be effective for locating all sounders. In each grid cell you should set out whole corn at sites with fresh pig sign, and set up a game camera on the bait. If the bait isn’t hit by pigs in three to four days, then move on. But, if a sounder is using the site, then keep on baiting and monitoring because this will be a future trap site.
STEP No. 2 — Identify Unique Sounders and Pigs: The cameras at each bait site can now be used to identify unique sounders and individuals. Individual sounders can easily be identified based upon unique pelage characteristics, total count, composition of adults and juveniles, etc. Sounders also commonly arrive at bait sites at the same time each night, and so timing of arrival can sometimes assist with identification. It’s important to ensure that you get an accurate count of all of the individuals in each sounder, because without that count, you can’t be sure that you removed all of the pigs.
STEP 3 — Construct Traps and Allow Habituation: Once you have detailed information about how many and which pigs are at bait sites, you can begin to set up traps. I recommend using the same location as where the cameras were located because the pigs are already accustomed to visiting those sites nightly. The best trap type is a corral trap, and the larger the door the better. Our data indicate that wild pigs are twice as likely to enter corral traps as box traps, and this trend is even more apparent with adult animals. Corral traps also tend to be much larger than box traps, so there is a greater probability of capturing an entire sounder at a single time. It’s essential that you do not set the trap immediately after construction. Tie the door in the open position, leave the camera in place where you can see the door and into the trap, and continue baiting. You must allow the pigs to become habituated to the trap, and you don’t want to set the trap until you have photographic evidence that all of the pigs are regularly entering the trap. The single, biggest mistake that trappers make is prematurely trapping pigs before they are habituated to the trap. This almost always leads to low capture numbers and a high number of trap-shy pigs. Once they associate traps with death, they will become much more difficult to capture.
STEP No. 4 — Trap the Pigs: When you know all of the pigs are regularly entering the trap, set the trap. There are a multitude of trigger types that can be effectively utilized to increase the probability of capturing the entire sounder. Root triggers can be very effective and there are multiple variations of this trigger type. Smart traps (live photos can be sent to your cell phone and you can remotely trigger the trap from your phone) are very popular today and have high capture rates, although they are too expensive for many landowners.
It is critical that you continue trapping until you get all of the pigs. If you get only the juveniles in the trap, let them go: You don’t want to educate the adults. They’ll come back in a few days. If you get all but one or two, keep trapping until you get those, too. It might take some time, but you can usually get them.
On occasion, you’ll have pigs that are too smart to enter the trap, and you might have one or two individuals that you can’t catch. This is where hunting (a more apt description would probably be “shooting”) becomes valuable. While you might not be able to get that last animal or two in the trap, you can almost always get them on bait. A single animal that is patterned on a bait pile with use of a game camera can easily be removed by a hunter. Even if the animal is coming in at night, most states have permits for night shooting of wild pigs just for this reason. Check with your state wildlife agency regarding how to obtain a permit.
STEP No. 5 — Continue to Monitor: After you’ve removed an entire sounder, continue to monitor the trap site to ensure that you didn’t leave any behind. Sometimes you can miss an adult female or two that have left the group to farrow (give birth). If you don’t continue to monitor after removing the sounder and there is a female that you missed, all of your work will be undone.
As I indicated, this trapping strategy was developed by some of my graduate students who conducted their research at Fort Benning, Georgia. Their research focused on an area of the installation that was approximately 20,000 acres in size. During the course of the study, they identified 17 unique sounders. In May of 2009, they removed the first two sounders, clearing approximately 2,000 acres of wild pigs. Then they monitored the response of the surrounding population for six months. They had affixed GPS collars to sows in all of the surrounding sounders and maintained bait piles with game cameras in the “pig-free” area.
During the six months of monitoring, no new sounders established themselves in the cleared area. At the end of the six months, they removed three more adjacent sounders, clearing another 2,500 acres. They once again stopped trapping and monitored wild pig activity for six months using GPS collars and game cameras. With the exception of one adjacent sounder expanding its home range to include approximately 100 acres of new space, the area remained free of wild pigs.
In summer of 2010, they began trapping the remaining 12 sounders and they cleared the remaining area of wild pigs. During all of their trapping, they removed 256 pigs, and cleared approximately 15,000 to 20,000 acres … with the exception of two females. Unfortunately, their time available for trapping was at an end and they could not get the last two. My understanding is that these two individuals were never removed from the base, and that they quickly recolonized an “island population” that was surrounded by an area that was pig-free.
There were two very important lessons we learned from this endeavor. First, wild pig populations can be eradicated if an appropriate trapping strategy is employed. Second, if you don’t get all of the females, they will quickly undo your efforts by replacing the pigs that you have removed.
Wild pigs are a scourge upon the landscape and devalue properties where they’re present. With the exception of a few hours of recreational hunting that they provide, they are of very little value. They cause considerable ecological and agricultural damage, and all evidence points to the fact that they reduce deer herd quality. Fortunately, there is something that can be done about it. While pig trapping is not as easy as snapping your fingers, hard work and persistence can significantly reduce, or even eradicate, wild pigs on your property. Just remember … it doesn’t matter how many you trap, it only matters how many you leave behind.
Of course, the easiest way to be pig-free is to not introduce them in the first place. Unfortunately, the desire to have a spring/summer big game animal to hunt has led to countless illegal releases of wild pigs across the country. State wildlife agencies are working hard to stop these releases, but they are going to need the help of concerned hunters, land managers and landowners to be effective in this endeavor.
Significantly reducing, much less eliminating, populations of wild pigs in an area might seem like a daunting task. Without question it will take considerable work and persistence. But it is doable, and the biology of wild pigs is what makes it possible. In most populations, wild pig social and spatial structure results in very slow movement across the landscape. What this means is that you don’t have to do this in a weekend, a month, or even six months.
Our data from Fort Benning show that you can remove a few sounders and take a break without overly worrying about losing all of the ground you just gained. Additionally, you don’t have to worry about trapping boars. While a boar likely causes more damage to the landscape than a sow, and also likely has a greater impact on deer than a sow, they don’t produce piglets. In essence, boars have no impact on population growth. And once you remove the females, the boars will leave on their own because they’ll be frequenting areas where there are females and potential reproductive opportunities. Be patient, don’t become overwhelmed, and don’t try and reinvent the wheel. Ask experts for advice, and approach pig removal as you would any other form of deer or land management that you take so much pride in. My guess is that you’ll enjoy the process … and I know you’ll enjoy the results.
— Dr. Steve Ditchkoff is a professor in the School of Forestry and Wildlife Sciences at Auburn University. He manages the deer research program at Auburn and has been conducting research on white-tailed deer for 25 years.
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