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Brace Yourselves… The Hogs Are Coming: 

Assessing the impact of feral hogs in North Carolina

Ellis Tinsley

          For many North Carolinians, learning that we have an exponentially growing feral hog problem may come as somewhat of a shock.  Unfortunately it couldn’t be closer to the truth and over the next decade this issue is going to get much worse.  Feral hogs create a significant ecological and economic burden, and if left unchecked have the potential to destroy hundreds of thousands of acres in our state alone and permanently alter the landscape for generations to come.

          Feral hogs are an invasive species to North America.  We have been able to identify three major explanations of how they arrived here.  Throughout the age of exploration, they were brought from Europe and Asia as domestic livestock.  A majority of these herds were free-ranging so they were easily able to escape, become wild, and begin the generations of interbreeding that is now coming back to haunt us.  Later in the 1890s, Eurasian wild boars were released on contained properties for hunting, where many were able to escape of course. Today, hog farms make up a large portion of North Carolina’s agricultural product.  Unfortunately with the mass quantities these farms produce, a power outage or a hole in the fence can release more pigs into the wild. 

          To understand the enormity of the situation, there are a few important facts about feral hog biology one must know.  As described above, there are three separate types of pigs that interbreed to create feral offspring: Feral hogs, domestic pigs, and Eurasian wild boars.  Female hogs (sows), have the ability to begin mating at about six months of age and can have one or two litters per year.  Each litter averages about four to six piglets so one sow can have around twenty offspring by her second birthday.  In North Carolina the only predators these piglets have are coyotes, bobcats, and foxes, but once they grow into adulthood none can kill them.  Adult hogs average range in weight is from 100-400 pounds and will eat anything and everything in their path.  Similar to our friendly domesticated canines, they have no sweat glands, which is why they wallow in mud and available water to cool off. 

          In a study performed by Rick A. Sweitzer and Dirk H. Van Vuren, it was discovered that rooting from feral hogs covers thirty-five to sixty-five percent of the land in places they classified as having high-density pig populations.  Rooting tears up the land so bad it contributes to substantial declines in biomass productivity, which in turn reduces the resources available for native trees and plants.  Their data revealed, “rooting by wild pigs in areas where densities exceed 2.0 pigs/km2 is contributing significantly to reduced tree seedling regeneration in oak woodland ecosystems” (Sweitzer and Van Vuren).  The pigs eat the acorns and biomass essential for tree growth, and the search for these items brings a considerable amount of harm to the young tree in its fragile state.   Not only are the pigs tearing up established saplings; they are also removing most if not all of the seeds.  As such, feral hogs in North Carolina will have a debilitating impact on our already dwindling population of hardwoods if the appropriate measures to stop them are not taken. 

          Texas A&M University allocates a considerable amount of resources towards the study of the impact of feral hogs.  According to their research, hog destruction in Texas averages around $52 million each year, and that is solely from damage to agriculture. As the animals are becoming more and more bold around humans, they have been known to venture into residential areas where they can cause millions more in damage.  Some reports that combine both residential and agricultural damage estimate costs of up to $400 million per year.    

          One of A&M’s more prevalent studies dealt with the link between feral hogs and riparian ecosystems that are similar to habitats we have here in North Carolina.  A major discovery from this work is that wild pig rooting in the upper soil layers leads to increased nitrogen levels in the soil.  The disturbance to the soil and leaf litter causes it to breakdown much faster than it should.  This process drastically increases nitrogen levels in the soil, which commonly results in two major problems.  First, the raised nitrogen levels are washed into water sources and can alter the quality so it is inhabitable for native species.  The second is that the nitrogen levels provide a healthy environment for Chinese tallow to grow.  Texas A&M researchers recorded over twice as much Chinese tallow abundance in rooted locations, and similar to other invasives, the plant has wreaked havoc on ecosystems in the South.  Better conditions for its growth in North Carolina could add another devastating impact to our growing list. 

          Now that the problem is clear, we fall to the age-old question of “so just what the hell do we do about it?!”  The North Carolina General Assembly made a fundamental statement about their position in 2011 when they changed the legal status of feral swine to indicate the population will solely be managed under the control of the NC Wildlife Resources Commission (NCWRC).  In coordination with the General Assembly, the NCWRC released two vital changes to regulations regarding the hunting of these animals, which give property owners a much higher chance of management success.   First, feral swine may be taken outside of standard shooting hours (½ hour before sunrise to ½ hour after sunset) with the aid of a light.  This gives landowners and managers the opportunity to catch hogs that have learned to feed nocturnally.  Second, feral swine may be caught and removed through trapping.  This is the most effective known method of management worldwide and NC would make no progress in these efforts if trapping were still illegal.

          Once signs of hogs are evident on a piece of property, drastic measures should immediately be taken to protect the ecosystem.  The best way to do this is through the use of a corral trap but there is a very important step-by-step process that should be followed to achieve the highest levels of success.

           The overall idea is to train the hogs to be comfortable entering the corral and feeding so finally you can trap them all at once.  First step is to find a location.  This should be somewhere the hogs frequently feed, but large enough to build the trap.  The next step is to put out feed in the location consistently at the same time for at least 2-4 days.  Once they are comfortable feeding at the site, the next phase is to begin adding sections to the trap.  Traps come in all shapes and sizes, but the most common are circular, ranging from 30-40 feet in diameter.  The trap should take the shape of a teardrop on one end where the trapdoor will go.  Build the trap by staking T-posts down in the desired shape and then running square-holed wire fencing around the posts.  Use bailing wire to secure the fencing to the posts.  Make certain the fence is sturdy because once the gate is closed a hog will take a running start and slam its 100-300 lb. frame into the fence attempting to escape.  Sections of the corral should be added over a period of 2-3 days again and the hogs should continue to be fed in the same manner as described above.  Once the hogs are comfortable entering and exiting the completed trap through an open gate, set game cameras to find out when the most hogs are in the trap at one time.  Finally, pick your optimal shooting time and depending on what type of gate is in use, set the trap and wait.  This method is ideal because anywhere from 10-50 hogs can be trapped and removed at once.  The hogs live together in “sounder” groups and the idea is to catch a whole sounder group at once.  Game cameras are an efficient way to judge the size of the sounder to find the highest number of hogs entering the trap at the same time.          

          State officials have done everything they can so far by relaxing legislation until more research into management techniques is complete.  They have left the fate of North Carolina’s wild spaces up to hunters and landowners.  Unfortunately, by the time this issue has become well known among all NC citizens I fear it will be too late.  At the moment, educating the public about the feral swine population and its potential impacts is of utmost importance to not only North Carolina but also the entire South.  By reaching a larger audience it is more likely a higher number of landowners will participate in management efforts.  For the sake of our trees and our land as we know it, the exponential expansion of feral swine in North Carolina must be controlled. 

 

Ellis A. Tinsley III

Class of 2014

Management and Society

Wilmington, NC

 

Bibliography

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