The wildlife you see on your next hiking trip? The rustle in your backyard at night? It might not be a raccoon or a deer.
A steady increase in the population of wild pigs — a marauding, non-native animal that can grow sharp tusks and weigh 250 pounds or more — is causing growing problems for parks, water districts and homeowners across the Bay Area.
The hogs wallow in streams, dig up lawns and gardens, eat endangered plants and animals and occasionally charge at people. They carry diseases like swine fever and can spread pathogens like E. coli to crops in farm fields.
“We’ve seen the impacts increasing,” said Doug Bell, wildlife program manager at the East Bay Regional Park District in Oakland. “They are omnivores. They vacuum up California quail, Alameda whipsnakes and other wildlife. They eat everything. They’ll come in and destroy lawns and all your landscaping overnight. Sometimes people can be hurt by them. We had a hiker who was run over by a wild boar and injured her leg. A firefighter was knocked down by one in 2020. They can be frightening.”
Hoping to slow the spread of the ravenous razorbacks, several large public land agencies are expanding their efforts to trap and kill the animals.
Last month, the Santa Clara Valley Open Space Authority, an agency in San Jose that has preserved 30,000 acres of land for hiking, biking, horse riding and wildlife, approved spending $243,000 to hire a contractor, Full Boar Trapping and Wildlife Control, based in Contra Costa County, to trap and shoot wild pigs over the next three years on its properties.
Typically, trappers set up circular net pens and bait them with fermented corn. The pigs enter and can’t get out. Sometimes temporary metal corrals are used, with gates that can be observed on video cameras and closed remotely. Trappers also use smaller cage traps. Because it’s illegal in California to release trapped wild animals elsewhere, the pigs are shot and often taken to landfills or rendering plants.
“We are seeing a lot more pig damage,” said Aaron Hébert, natural resources manager with the Santa Clara Valley Open Space Authority. “Trying to control the population and not just trying to haze them is now part of the strategy.”
Domestic pigs first came to California in 1769 with Spanish explorers. But things went hog wild starting in 1924. That’s when George Gordon Moore, an eccentric Canadian millionaire, purchased Rancho San Carlos, a 22,000-acre ranch in Carmel Valley. He held polo matches and hosted lavish parties with movie stars and wealthy Jazz Age captains of industry.
To hunt with guests, he introduced Russian boars. Not surprisingly, some escaped. They bred with local pigs and spread far and wide. Now they are in 56 of California’s 58 counties.
The animals are legal for sport hunters to shoot, like deer or ducks. Last year, 3,327 wild pigs were reported killed by hunters in California, according to the state Department of Fish and Wildlife.
But their population keeps growing. Females can have up to two litters per year, with as many as 10 piglets per litter.
There aren’t exact population totals. But from 2013 to 2017, 489 pigs a year on average were killed by the East Bay Regional Park District, East Bay Municipal Utility District, and state parks in Contra Costa and Alameda counties, according to a study by East Bay Parks. That number doubled to 944 between 2018 and 2022.
In December, East Bay Parks published a plan it compiled with other agencies to do more. The study showed that the animals, found commonly around Mount Diablo, Calaveras Reservoir and the Dublin Hills, would grow tenfold without a hunting and trapping program.
It recommended agencies work together to use drones with thermal imaging to track the pigs at night, fit some with GPS collars, put fencing around sensitive areas — although that can cost $20,000 a mile and block other wild animals — collect better data, and enlist the public’s help through a hotline or website to report sightings.
“We are trying to go from being reactive to proactive in the wider region,” Bell said.
In the South Bay, the Santa Clara Valley Water District in December signed a five-year, $125,000 contract with the U.S. Department of Agriculture to trap and kill wild pigs on land it owns at Anderson Reservoir and Coyote Ridge east of San Jose.
After the water district drained Anderson Reservoir in 2020 to replace its aging dam for earthquake safety, wild pigs began coming out of the Diablo Range. They would walk across the dry lake bed, and wreck lawns in the Holiday Lake Estates neighborhood and other residential areas between San Jose and Morgan Hill.
“In some cases, there are 25 or more pigs at a time,” said Sean Mulligan, a Holiday Lake Estates resident. “They are doing damage. People are building fences. They are causing hillside erosion, digging into lawns.”
For several years, water district officials told angry residents there was nothing they could do. The residents got a lawyer and argued the district was violating the California Environmental Quality Act by not dealing with the problem as part of the dam project.
“We didn’t have any activity until they drained the lake,” Mulligan said. “Then the pigs started showing up.”
Since January, trappers have killed 24 wild pigs around Anderson Reservoir and at nearby Coyote Ridge, said John Bourgeois, a deputy operating officer of the district,
“This is an effort to be a good neighbor,” he said. “It’s been in the works for a while.”
Multiple land managers said three wet winters in a row in Northern California have caused an increase in grasses, acorns and other food for wild pigs, which is believed to be why their numbers are growing steadily.
“We do get complaints,” said Bell, of East Bay Parks. “People will call up and say, ‘Your pigs are destroying our property.’ When 10 or 20 run through a neighborhood, it can be kind of frightening if you have small children and pets. We respond to that and increase trapping. But it’s a constant effort.”
