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Unwelcome Invaders: Wild Pigs Pose a Serious New Threat to Idaho

Exotic species threatens agriculture, the environment and wildlife


Somewhere in the High Desert scrub of Southern Idaho lurks a threat that has wildlife and public land managers nervous. They're nervous that somewhere, amid the sagebrush, grasses, brambles and cattails a threat is multiplying, and if they fail to take control of the situation now, it could turn into a nightmare not only for them, but landowners, farmers, ranchers, hunters, fishermen and the state.

This threat isn't one of the more notorious or controversial wildlife species. It has nothing to do with developers. It comes with a snout.

Other parts of the country are already feeling the jarring blow of wild pigs--also called feral hogs when the pigs are escaped domestic swine--with some of the hardest-hit areas spending tens of millions each year just trying to keep problems from getting any bigger. Now, with confirmed sightings of wild pigs near Bruneau, officials in Idaho are trying to stop the issue before a population has the chance to take root.

The idea of pigs wandering around the desert hardly seems like a threat to most people who imagine rotund, pink barnyard creatures. But these little piggies are hardly harmless. Wild pigs can annihilate crops, destroy riparian areas, decimate wild bird populations, be a threat to both livestock and wildlife, and have the potential to carry a variety of diseases that pose a risk to both domestic and wild animals, and in some cases, humans.

"It's an ecological train wreck," said Mike Bodenchuk, state director for the Texas Wildlife Services Program, the agency that oversees control efforts in the Lone Star State.

Bodenchuk is at the center of the storm when it comes to the increasing problem of wild pigs in the United States. Researchers now estimate wild pigs are in 39 states. While getting a population estimate for a species that is notoriously smart, evasive and can become nocturnal is difficult, Texas authorities believe there are between 2 million and 3 million wild pigs in Texas alone. To put that number in context, Bodenchuk points to the fact that there are roughly 4 million white-tailed deer in Texas.

While wildlife managers in Idaho are hesitant to put a figure on just how many wild pigs there were when their presence was confirmed, Pam Juker, communications director for the Idaho State Department of Agriculture, said her agency estimates the population in 2009 to be somewhere between 50 and 100 animals.

That number has been reduced due to a combination of hunting and agency efforts, although an exact number of pigs taken by hunters is impossible to know since Idaho doesn't regulate wild pig hunting--only a valid hunting license is required. Additionally, the remaining pigs are elusive quarry in the expansive landscape.

"It's difficult right now, and it's a little frustrating because we're basically chasing ghosts," said Brian Flatter, senior conservation officer with Idaho Fish and Game whose 2,300-square-mile patrol area is where the wild pigs are active.

Major populations of wild pigs can be found throughout the South and California, but in recent decades, the pigs have managed to expand their range as far north as Michigan and even have a sizable foothold in north central Oregon.

Currently, the wild pigs in Idaho are confined to the Bruneau Valley, but some wildlife managers are concerned that if hunting pressure increases, they may be motivated to move downriver.

"They're very adaptable. They can live in nearly any environment as long as they have food and water," said Scott Stopak, a wildlife disease biologist with the U.S. Department of Agriculture's Wildlife Services division based in Boise.

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Bill London, district conservation officer with Idaho Fish and Game, added that both the Bruneau and Snake rivers could be enticing migration corridors for the water-loving pigs.

Wild pigs aren't a native species anywhere in North America, so the question arises: How did they get here in the first place? The blame goes all the way back to some of the earliest European explorers, including Christopher Columbus, who would routinely release pigs or goats on new land as a way to build up a future food supply for possible colonists or shipwrecked sailors.

Turns out, pigs are very, very adaptable and very, very prolific breeders. Wild pigs can start breeding when they're as young as 6 months old, are capable of having between four and eight offspring per litter and can have multiple litters in a year. Rabbits don't have anything on these guys.

Wild pigs are also big: typically, adult pigs weigh between 75 and 250 pounds and range from 50 to 75 inches in length. On rare occasions, they can be larger. In 1965 a wild pig weighing 893 pounds was killed in South Carolina.

Some of these largest pigs are thought to have been raised in domestic situations and then either escaped or were released. In just three generations, domestic pigs that escape or are allowed to roam free can revert to wild form, including thicker hair, a narrower head and long tusks, according to Stopak.

Wild pigs have gotten an even bigger hand from man in recent years as the popularity of hunting them has increased. In many of the cases in which only pockets of wild pigs have been found, officials believe they are the result of individual hunters secretly releasing a few pigs in the area so they can hunt them closer to home. Not only is the action illegal in most states--including Idaho--but it often creates unanticipated nightmares for wildlife and land managers, as well as private land owners. If someone is caught releasing wild pigs--an exotic species--in Idaho, he or she could face felony charges from both the Department of Agriculture and Idaho Fish and Game, punishable by both jail time and fines if convicted.

An illegal release is suspected in the case of the Southern Idaho wild pigs, but officials don't have evidence to confirm the belief.

What they can confirm is the presence of wild pigs in the area near the C.J. Strike Reservoir. Rumors began in 2007, when bird and coyote hunters began talking about occasional sightings of pigs in the desert. Those rumors were confirmed in 2009 when London and other Idaho Fish and Game officers met hunters who had killed a wild pig. The reports were further confirmed when officials with the USDA's Wildlife Services division captured photographs of the pigs on trap cameras set up in the area of suspected pig activity.

Area landowners were some of the first to notice the presence of the wild pigs in the area, including the Colyer family, who runs a Hereford and Angus cattle ranch.

Sherry Colyer said they first spotted the pigs and the damage they had done to the fields several years ago. The sightings raised immediate red flags for the family.

"We were extremely concerned," Colyer said. "They populate like rabbits, they will ... go through a crop of corn really quick and do a lot of damage in the fields."

Colyer said that after the sightings and hearing of damage to neighboring corn fields, her father-in-law began to trap the pigs on his own, eventually capturing roughly six to eight animals.

Even then, they knew there were more out there and began working with Idaho Fish and Game to monitor the situation and try to trap more pigs.

"It's distressing to think that if you don't keep them out ... that you're going to end up with a big mess," she said.

Since then, an interagency group has been working not only with each other but also with private land owners to get rid of the wild pigs before they can overwhelm efforts.

Because of Idaho law, wild pigs fall under the oversight of the Idaho State Department of Agriculture, since they are considered livestock. Like in many states though, oversight and responsibility aren't clear-cut because so many agencies are concerned with the issue. While Idaho law expressly bans the import and release of wild pigs, the department isn't suited to deal with the problem on its own. The department is working closely with USDA Wildlife Services, as well as Idaho Fish and Game to come up with an approach to the issue.

Regardless of the agency, no one wants to see the pigs become a permanent presence in Idaho.

"It's just a disaster," Stopak said. "It's not like it's one problem they create. They're very destructive animals."

"We certainly don't want them to take off," said Steve Nadeau, regional wildlife manager for the Southwest Region of Idaho Fish and Game. "It's opening up a whole Pandora's box with a whole suite of issues down the road."

Officials are now dealing with those issues in Oregon, where wildlife officials estimate there are now between 1,000 and 5,000 wild pigs on a patchwork of public and private land in north central Oregon.

For years, there were anecdotal reports of wild pigs in the area, but recently the issue has hit the front lines as both private landowners and public managers are seeing greater damage on the landscape.

Oregon's population is believed to have stemmed from two sources: private landowners introducing the species for their own hunting and an exotic hunting business from which some wild boars may have escaped, according to Keith Kohl, terrestrial invasive species coordinator for the Oregon Department of Fish and Wildlife.

For the last several years, the department, along with USDA Wildlife Services and the help of some of the private landowners, has been trapping pigs, but the extent of the population is still widely unknown since much of the activity is on private land and not all landowners have been willing to take part in the effort.

Still, the issue is of such concern that last year the Oregon Legislature passed House Bill 2221, which outlawed the selling or advertising of hunts for wild pigs. The bill also requires that any private landowner who finds wild pigs on his or her property report them within 10 days and work with agency officials on a removal plan. The law also transferred authority over wild pigs from the Oregon Department of Agriculture to Fish and Wildlife.

Even with the law in place, cooperation has been spotty at best.

"So far we've had three plans," Kohl said. "A lot has to do with landowners and government regulations. They're wary of raising their hands."

Oregon is facing the challenge of not only discovering the size of the population and figuring out how to reduce it but also finding funding. Kohl said his agency is working on getting funding from non-governmental agencies to match state funds.

Oregon is also exploring ways to learn more about the wild pigs that are already out there. Kohl said officials there are experimenting with a technique known as the Judas pig in which a wild pig is trapped and fitted with a radio telemetry collar before being released. The hope is that not only will the tagged pig lead them to larger groups, making trapping more effective, but the information will tell researchers more about the pigs' home range, how far they travel in a day and how long they're spending in one area.

"We're trying to do things to make it easier for the landowner, to make it easier to get rid of [the pigs]," he said.

Kohl said the resistant landowners largely don't think the pigs are a big deal, and many like the idea of being able to hunt them. But many change their opinions when they are shown the extent of the damage the pigs are capable of.

"When they see the damage, they understand the problem," Kohl said.

"It's amazing the amount of damage a group of pigs can do. It's just like a rototiller going through," he said, describing how one rancher's meadow grazing area was destroyed by wild pigs.

"[You have to show landowners] what it can do in their pocketbook," Kohl said.

But he admits that the key to accomplishing any reduction is to work with the private landowners.

"Without access, we can't do anything," Kohl said. "Like with a lot of things ... you have to show by example--show that we're out there trying to help them solve the problem, not force anything on them.

The damage wild pigs can do is both very real and extensive. From the Department of Agriculture's perspective, top concerns include the destruction of crops and rangeland, as well as the possibility of transmitting diseases from wild pigs to their domestic counterparts and jeopardizing the state's livestock industry standing.

Wild pigs' most common foods include roots, tubers and assorted vegetation, and they are able to get to those food sources with impressive efficiency. They use their snouts to root below ground level, tearing up surface vegetation. This not only gets them a good meal, but it means that a group of pigs--known as a sounder--can effectively take out an agricultural field overnight.

This rooting activity also makes them the bane of wetland and riparian areas since not only does the rooting lead to erosion, but increased sediment in the water can damage fish spawning areas. Additionally, the rooting can make it all the easier for noxious weeds and other invasive plant species to take hold.

Wild pigs--as well as domestic pigs--are equal opportunity eaters, meaning they will eat just about anything if given the chance. This puts everything from amphibians and worms to ground-nesting birds and their eggs to the occasional lamb or calf on the menu.

Idaho Fish and Game officials are particularly concerned with ground-nesting bird populations, including ducks, geese, pheasants and quail. Concerns are especially significant considering the area where the pigs are active overlaps a wildlife conservation area that is the nesting ground for a large population of waterfowl.

Flatter said there is evidence the pigs have been taking advantage of the birds.

"They're pretty opportunistic," he said. "Given a nest full of eggs, they'll eat them."

Just like the dietary preferences of wild pigs, the diseases they carry aren't too particular. Wild pigs can carry diseases that have been largely eliminated from domestic livestock, including swine brucellosis and pseudorabies. Unfortunately, some of these diseases aren't species-specific and can jump not only to wildlife but to humans as well.

The swine form of brucellosis (slightly different from the form found in large ungulates like elk and bison in the Yellowstone area) not only can kill animals but can be contracted by hunters while handling the carcass of an infected wild pig if they don't wear protective gloves. If a human is infected, the disease usually causes flu-like symptoms.

Pseudorabies is a form of the herpes virus and is not only fatal to wildlife but is of particular concern to hunting dogs.

"The unfortunate part [is] that with feral swine, they can harbor so many diseases but live with it ... if it gets into [the domestic] population, the amount of resources to control that are going to be enormous," Stopak said.

Wildlife Services has taken samples of all wild pigs trapped in Idaho, and to date, there have been no positive results from tests.

It's because of the health risks that livestock groups, including the state's pork industry, are supporting efforts to eradicate wild pigs, including providing financial support.

"Idaho is a brucellosis-free state and pigs could jeopardize Idaho's status," Flatter said. "You don't want to have that kind of a mark on your state. You don't want any potential negative issues.

"Anytime you bring wildlife into the state, it has to be inspected," Flatter said. "We don't have [native] wild hogs here. If any are brought in, the Department of Ag would not let them into the state ... Any time you're releasing wildlife, it just causes problems."

The wild pigs issue is one of the rare moments in which wildlife managers, agricultural groups and conservation groups are on the same side.

"It's a little unusual for everyone to be on the same page," said Justin Hayes, program director at Idaho Conservation League. "It's not just environmentalists saying this, it's sort of like all the various constituencies have concerns because everyone has something on the line."

Hayes said his organization is in full support of the efforts to remove wild pigs, including unlimited shooting and aerial gunning.

"Feral pigs are really destructive to the natural environment," he said. "We need to do everything we can to get rid of feral pigs in Idaho ... they need to be shot out of the state."

While Idaho and Oregon are in the early stages of learning to deal with wild pigs, Texas has been dealing with them since before it was an actual state. Historically, pigs were allowed to roam free, and people would occasionally have hog roundups, said John Young, mammalogist with the Texas Park and Wildlife Department.

But in the last few years, wild pigs in Texas have gone from an inconvenience to a major issue.

"There's no part of our environment that they don't impact," said Texas Wildlife Service's Bodenchuk. "They compete with native wildlife, they spread invasive plants, add E. coli to the watershed, eat endangered reptiles ... it's a train wreck that impacts us all."

Between 2003 and 2007, Bodenchuk said the wild pig population in Texas expanded by 20 percent per year. Even more telling is the fact that in 1982 the state killed 83 wild pigs, but by 2009 that number rose to 24,680, and the population is still considered out of control.

"We reached critical mass," he said. "We finally got enough pigs in enough places that we had populations interbreeding with each other. Populations grow slowly for a while, but once the second or third litters have their own litters, you have an exponential growth curve."

Bodenchuk's job has expanded to include traveling to other states to talk about the issues surrounding wild pigs.

"We serve as the bad example of what happens if you let it get out of control," he said with a resigned laugh.

Bodenchuk said Texas officials are using every method available to try to control the wild pig population, including trapping, snares, hunting, night-vision equipment and aerial shooting, which he said is the most cost-effective tactic.

But dealing with wild pigs is not cheap. Pigs cause an estimated $52 million in damage to just agricultural fields and pasture lands in Texas each year, Bodenchuk said, adding that the state does not compensate private landowners for damages. It breaks down to roughly $400 per pig per year. One 2007 study partially funded by the USDA estimated that damage to crops and the environment by wild pigs nationally is roughly $1.5 billion annually.

The ecological impact is harder to measure, but he points to the efforts to save endangered sea turtles, whose eggs wild pigs treat like an all-you-can-eat buffet.

"We're spending millions trying to beat the pigs to the nests," he said.

With 2 million wild pigs, Bodenchuk said eradication is off the table in Texas, but he still has hope that the population can be knocked down to manageable levels. He believes that with current technology and the cooperation of enough landowners, levels could be brought down by up to 70 percent.

To help in the effort, Texas researchers are working with an international group of scientists to create toxicants (poisons) that will work on wild pigs without endangering other wildlife.

Work is focusing on sodium nitrate--ironically the preservative in bacon--which limits red blood cells' ability to carry oxygen, which would basically put the pigs to sleep for good. The chemical is not dangerous to humans since we have a natural ability to counter the effects. Yet the challenge remains in creating a delivery system that wild pigs could get into but other wildlife couldn't. At this point, Bodenchuk said, wide use of the toxicant could be three years away.

In Texas, there are a few small slaughterhouses that specialize in processing wild pigs, taking advantage of the fact that it is legal to sell wild hogs as long as they are brought in alive for a pre-mortum inspection and the processing must be kept separate from other animals. Bodenchuk said roughly 90 percent of the meat is shipped out of the country as sausage.

The downside of the arrangement is that most markets will only accept pigs larger than 60 pounds, giving trappers a reason to release smaller pigs, Bodenchuk said.

Of course, the chance to go after a tough and elusive prey is tempting for some hunters. And while they might not go so far as to bring wild pigs into the state, they aren't opposed to taking advantage of an opportunity presented to them. It's because of this that wildlife officials have seen a bit of resistance to their efforts to get rid of the wild pigs in Idaho.

"They want to maintain it because they think it's fun," Flatter said. "They're not releasing more pigs, but they're keeping a low profile."

Hunters have played a key part in the effort to find the wild pigs by providing reports of sightings, as well as removing a fair number of pigs themselves.

"[Hunters] have probably killed more than the agencies have," Flatter said. "They had a jump on them. By the time we got up and rolling, the numbers of pigs were greatly reduced than they were four to five years ago."

In both Idaho and Oregon there is no season for wild pigs, which means hunters just need a valid hunting license. It also means there is no bag limit.

But before ambitious hunters grab their rifles, wildlife officials in both states point out that the pigs range across both private and public land, and there are some seasonal closures on public land.

While hunting would seem to be an effective way to keep populations in check, the overall impact of hunting is minimal.

"Anyone who shoots a feral hog is a friend of mine," Bodenchuk said, but quickly added that recreational hunting will never control the population. He pointed to reports from German game officials--where wild boars are actually a native species--that in a single year 600,000 wild boars were harvested, yet the population is still not in control.

"It's never worked anywhere in the world yet," he said.

Some states, including Kansas, are even banning the hunting of wild pigs in an effort to discourage hunters from bringing the species into new areas.

Still, many landowners in the area are working with state officials to trap the pigs as they learn more about the potential damages. Flatter said one landowner in particular started trapping on his own and has been rather successful. While hunters killed an unknown number of wild pigs last year, wildlife officials killed only one.

Landowner cooperation comes in part from a series of meetings in the Grandview area in which public officials explained the issue to area residents.

"We met with a lot of locals and businesses, and they were all on board," said London, adding that conservation groups were supportive of the plan as well.

"[It was nice] that we had everyone working together," he said.

The interagency team is working to first find where the remaining wild pigs are, and then to figure out how to get rid of them.

While officials say finding a limited number of pigs in a densely vegetated area is tough, they haven't emptied their tool box just yet. Bird hunting in the adjacent areas closed for the season at the end of January, allowing crews to track and attempt to capture the pigs. The timing means that not only will there be fewer people in the area, but it happens to be the best time of the year to track pigs since the foliage isn't filled in. The area is also subject to a spring closure to protect ground-nesting birds.

Officials have used hounds to try to track the pigs, but they're holding on to their last tool--aerial gunning.

"We have money for aerial gunning if the conditions are right," Flatter said, adding that efforts have been made to spot the pigs from the air during other missions.

However it's done, there is one goal: eradication. That last push is the hardest.

"It's much easier removing the first 20 than the last two," said Stopak.

"The problem is they can reproduce so fast, if you don't get all of them, it wouldn't take very long for them to rebound," Stopak said, adding that researchers estimate that 70 percent of the population would have to be removed each year just to maintain a stable population.

Bodenchuk has some advice for states who are facing wild pigs.

"Just say no," he said. "Get on them and get on them quick. We're spending several million a year--half a million directly from the Legislature--just trying to control feral hogs in Texas, and we're just chipping away at the edges. A single incident can be massive."