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From the October 2012 Conservationist

A dark brown, furry feral swine

Pigs Gone Wild

Feral swine threaten New York State

By Eileen Stegemann

Standing at the edge of the cornfield, looking at the upturned earth and destroyed crops, I think to myself, "Pigs did this?"

Cornfield damaged by feral swine
Damaged crops

I'm with DEC Wildlife Biologist Ed Reed, who has taken me to an upstate farm where feral swine (a.k.a. wild pigs) have been wreaking havoc for more than a year now. The area is a small patch by Ed's standards, but the damage is no less dramatic. Stalks have been broken and trampled, corn only half-eaten, most likely the result of another ear looking more delectable. For the farmer, this is devastating and in these tough economic times can mean the difference between remaining solvent or going under. Regardless, it's clear something must
be done.

We walk into the woods bordering the property to scout for more sign of pigs. There is evidence everywhere-broken twigs, tracks, turned-up ground, semi-dry muddy patches used as wallows-most several days old, but no pigs. Of course, we weren't really expecting to see pigs because they are most active at night, but it didn't stop me from hoping.

The pigs raiding this farm are Russian boars, escapees from a nearby property whose owner was raising them for game. As Ed laughingly describes, they are "large and in charge," formidable animals that can become very aggressive when they perceive they are threatened. Despite their size, they can run fast-up to 30 mph. Imagine a 300- to 400-pound, animal with razor-sharp tusks charging you. You get the picture.

However, Ed explains, "It really wouldn't be much different if these were escaped domestic or 'pet' pigs, as even these will revert back to their wild state in a relatively short time. And that doesn't mean the next generation-the actual escapee will begin to grow hair and tusks in the wild." I'm astounded at this news, and yet the biologist in me is fascinated.

As we continue to scramble through the underbrush, heading deeper into the woods towards the swampy area where Ed suspects the pigs spend the daylight hours, he explains that in the years he's been doing this, he's only seen actual pigs twice. But he's heard them a number of times at night, moving around in the cornfield, seemingly confident in their ability to elude capture. In Ed's words, they are extremely wary, incredibly smart, and fearless when confronted, a combination that makes them difficult to catch.

A green metal feral swine corral in the woods
Biologists use corral traps to try and
capture feral swine. (Notice the trail
cam on the tree at right.)

Showing me a large corral trap hidden in the woods, Ed explains some of the methods he and his coworkers use to lure these crafty animals. To avoid spooking the swine, biologists and technicians take weeks to painstakingly habituate the pigs to come to a particular spot by putting out bait. Continuing to provide bait, DEC staff then slowly bring in and set up the corral one section at a time. For the enclosure in front of me, this took more than two weeks. The pigs showed up faithfully, chowing down on the free food. That is, until the last piece of the corral-the gate that springs shut to trap the pigs-was added; then the adult pigs wouldn't venture inside. It's as if they knew it was a trap. So as I stood looking at the empty enclosure-gate wide open, the center freshly baited with corn-I couldn't help but sympathize with the biologists and the landowner. Fortunately, however, piglets are not as savvy as adult pigs and will venture inside in pursuit of an easy meal. Because of this, a couple of weeks before my visit, DEC staff captured 16 piglets. Interestingly, trail cams set up in the area captured images of adult pigs standing all around, but remaining outside the enclosure.

Ed also took me to a tree stand set up near a baited pile on the outskirts of the field. Despite being manned many a night by DEC staff, they only managed to get half-a-dozen adults. As Ed says, "The pigs know we're there and so avoid that area. Once we leave, they come right back." DEC has many a trail cam picture of numerous large pigs-as well as raccoon, deer and rabbit-visiting the bait pile.

Adult feral swine and piglets

What compounds the problem of controlling feral swine is that they are extremely prolific. In fact, a single female (sow) can have two to three litters of six to eight piglets each year. And the sows can start breeding as early as 6-10 months of age. That means that a few can quickly become an extended family, which in turn can quickly become a very large group. The numbers are alarming. Fortunately, New York winters limit feral swine reproduction to the warmer months. It's a small consolation, but one our biologists are grateful for. In the southern U.S., feral swine can reproduce year-round.

Feral swine are also highly adaptable and can live most anywhere near water. Combine this with the fact that they will eat pretty much anything-from acorns and roots to tree seedlings and farm crops, and from reptiles and amphibians to birds and young wildlife-and you can understand why it's so hard to contain them.

New York is actually a relative newcomer to the feral swine epidemic. Feral swine have long been wreaking havoc across parts of the U.S. Like the group Ed is battling, the majority of feral swine are the result of escapees from farming operations or enclosed game and swine shooting preserves, but some are from deliberate releases. The Wildlife Society's June 2011 newsletter stated: "Free-roaming wild pigs have become one of North America's most threatening invasive mammal species. Spreading fast, they now number up to six million across at least 37 U.S. states and four Canadian provinces, where they are destroying crops, ruining property, killing livestock, fouling waterways, and spreading disease. Fat, mean, and prolific, these pigs pose enormous challenges for wildlife professionals."

Night-time trail cam photo of a group of feral swine in the woods
A DEC trail cam caught this image
of a group of feral swine in upstate
New York.

Despite battling this group of pigs in northern New York for a while, Ed says that upstate N.Y. is relatively lucky. At present, there are only a few established groups. Across the state, near Cortland, however, the USDA has been battling a number of pockets of feral swine since the first known group was discovered there about a decade ago. Currently, these destructive animals have been documented in at least 38 counties, with breeding confirmed in six. And that's just the ones we know about­­-the numbers are always changing.

The more I learn about feral swine, the more I realize just how important and difficult a task it is for DEC to control them. And just when biologists think they've gotten the problem under control, another group of pigs crops up. It's the ultimate game of cat and mouse; in this case, its hard to tell who's winning.

A white feral swine digs a trench in a lawn
Swine, including this pet pig, can
cause serious damage to the
landscape when rooting for food
or wallowing in wet areas. (Photo:
Kelly Stang)

The reality is that swine are here and must be dealt with before they do too much more damage-not just to the landscape like farm crops and lawns, but also to our native species. Feral swine directly compete with local wildlife (such as deer, bear, turkey, squirrels and waterfowl) for food and space, and they cause serious damage while rooting for food or when wallowing in wet areas where they destroy native vegetation, cause erosion, and negatively affect water quality. These invasives also disturb and prey on the nests and eggs of ground-nesting birds, snakes, lizards, frogs and salamanders, and will kill and eat fawns and young domestic livestock. In addition, they eat almost any agricultural crop, as well as tree seeds and seedlings, and tear up lawns and golf courses in search of tender roots, grubs and worms. Feral swine also pose potential health risks to native wildlife, livestock, pets and humans as they can carry pathogens like E. coli and transmit at least 30 diseases including swine brucellosis, trichinosis, and pseudorabies.

As Ed and I get in the truck to head back to the office, I ask him if he thinks DEC will be able to win this battle, and without hesitation he says that he and the other biologists are confident we will eventually be able to get feral pigs under control. It may just take a while. In the meantime, DEC will continue the fight, capturing as many feral swine as they can, and seeking ways to prevent new introductions of these destructive animals.


Eileen Stegemann is the assistant editor of Conservationist.

Photo: USFWS/ Steve Hillebrand