"They’re the most destructive mammal out there.”

[FYI. For Your Interest.]

Wily, Elusive Foragers Invade Upstate New York.

They roam by night, picking cornstalks clean, making off with apple crops. They have almost no natural predators, but they have razor-sharp tusks and a seemingly bottomless appetite for plants and animals. Their population can triple in one year.

They are feral pigs, and while they have long plagued parts of the Southern and Western United States, now they have become a problem in the peaceful Champlain Valley of New York, an agricultural heartland on the edge of the Adirondacks.

Actually, they are rarely spotted. Since they hunt at night and steer clear of humans, few people ever see these pigs. But a pack of them was captured on camera foraging on Bob Rulf’s farm here, their eyes eerily aglow in the light of the flash. “I have yet to see one myself,” Mr. Rulf said.

Mr. Rulf, 82, thought he had a deer problem. But when he dispatched a hunter to take care of them last spring, he learned the more disturbing truth.

Alternately called wild boars and feral swine, the pigs are not the gentle, pink cousins of Wilbur from “Charlotte’s Web,” E. B. White’s children’s classic. They start to breed as early as 6 months of age, bearing litters of as many as 10 piglets. They carry disease and can be aggressive toward people. They have even inspired a new television series, “Hogs Gone Wild,” about efforts to hunt them from Hawaii to Alabama.

Perhaps most worrisome is their reputation as eating machines: the pigs devour ground-nesting birds and reptiles, fawns and domestic livestock, native vegetation and crops. Feral pigs have already proliferated in parts of western New York. But state officials are drawing a line in the topsoil, so to speak, determined to protect both the agrarian economy and the fragile ecosystem from the nascent herd — or “sounder” in swine-speak — in the town of Peru.

“There’s a real sense of urgency,” said Ed Reed, a wildlife biologist for the state’s Department of Environmental Conservation. “Once the pigs get established, they are very difficult to eradicate completely.”

Hunting the animals is tricky, given their nocturnal nature. State officials have settled on trapping as the best way to capture an entire sounder of swine. To that end, two technicians have been slowly assembling traps on Mr. Rulf’s property — corrals, 30 feet in diameter, in which dried corn and doughnuts laced with Jell-O powder are luring the estimated half-dozen pigs troubling his farm.

With each extension of the traps, the pigs here have grown wary, staying away for a couple of nights before returning to nibble the bait. Officials hope that by the end of March, the pens will be finished and the pigs sufficiently acclimated to allow technicians to set trip wires closing the gates. The traps are circular because feral pigs have been known to crowd into the corners of other traps and climb atop one another to escape.

Last year, the state set a similar corral trap too soon, catching only three pigs. After that, none of the others returned to the area, even after the trap was dismantled. “I’ve never worked with an animal this smart,” Mr. Reed said.

Farmers in the region are nervously following the clash between the boars and the bureaucrats. “With all the agriculture here, the pigs have plenty of food,” said Peter Glushko, supervisor of Peru, a town of 7,000 on Lake Champlain, nine miles south of Plattsburgh. “Who knows where they’ll end up? Other farms should be concerned.”

The growing population has a number of origins: domestic livestock and pet pigs that were either released or escaped captivity; Eurasian boars imported for use on hunting ranches; and a hybrid between the two. Some researchers believe that pigs were most likely introduced to North America by Christopher Columbus in the West Indies; American settlers later brought more pigs as livestock. The practice by farmers of allowing pigs to roam on open ranges continued in some states until the 1960s, furthering their expansion into the wild. So far, feral pigs have infiltrated 5 of 62 counties in New York State. They first showed up about a decade ago in neighboring Onondaga and Cortland Counties, and the statewide population is estimated to be a few hundred, according to Justin Gansowski, a wildlife disease biologist with the United States Department of Agriculture in Castleton, N.Y.

By contrast, the feral pig population nationwide is a staggering five million, with the animals present in 35 states. Texas, Florida, Alabama and California are among the states with the highest concentrations of pigs, which benefit from warm climates and year-round availability of food.

New York State’s swine population has grown more slowly, possibly because of the cold climate’s impact on litter size. The Peru group, once estimated at 18 pigs, has been whittled by collisions with cars, hunting and trapping. While most pigs weigh between 100 and 150 pounds, one pig captured in Peru was an impressive 300 pounds.

Wildlife managers and researchers nationally are exploring various control measures, from contraceptives and poisons to snares and aerial shooting. Some are even taking cues from the military by employing night-vision equipment and thermal imaging to track and kill the pigs.

In New York, the state’s ordinarily strict hunting rules have been relaxed for feral swine. The Department of Environmental Conservation’s Web site advises those with small game licenses to “shoot and keep feral swine at any time and in any number.”

Rumor has it that Mr. Rulf’s pigs are descendants of Eurasian boars raised by a local man to sell to hunting preserves, although state and local officials have not confirmed that. Regardless of their origin, officials are not taking chances in halting the pigs’ progress, especially toward the six-million-acre Adirondack Park, the largest swath of pristine wilderness in the Northeast.

“They eat everything,” Mr. Reed said. “They’ll eat the understory in a forest and dig up plants by rooting the ground for insects and roots. They compete with wildlife for food. They’re the most destructive mammal out there.”