Besides the coyote, what would you guess is the most problematic type of wildlife in California?
Mountain lions? Hawks? Bears? Landscape-munching, car-wrecking deer?
Wrong. Try pigs.
"They are a major problem in the county," Sonoma County Agricultural Commissioner Tony Linegar said. "We deal a lot in agriculture with problem pig cases."
In 2012, farmers and landowners asked for help from the commissioner's two animal control agents almost 900 times: Coyotes accounted for 736 calls. Pigs came in second with 80 calls, more than twice the number of calls for all other animals combined, including mountain lions, bears, raccoons, and skunks.
The problem with pigs is that they breed prolifically, producing two or three large litters per year, so they can spread across the landscape exponentially. Even worse, they will eat nearly anything they can get their mouths on, from grubs, weeds, and acorns all the way up to small mammals, birds and amphibians.
The pigs, known technically as "feral swine," are the rough and tumble descendants of European and Asian pigs brought to the New World in waves, starting with the earliest Spanish explorers, right up to today's modern pig farmers. Some animals were released deliberately on the land, often for hunting purposes, and others escaped from farms.
Until the 1950s, wild pigs were found only in a few coastal counties in California, but now they have spread to nearly all parts of the state, excepting the driest deserts and coldest mountaintops.
In the East Bay, news outlets reported in September that a herd, known as a "sounder," of at least 20 pigs had devastated yards throughout the suburban city of San Ramon. In San Jose, meanwhile, the problem has become so great that the city council there passed an emergency ordinance in November allowing property owners to shoot the pests inside city limits.
Federal wildlife officials alone report killing more than 32,500 feral pigs in 28 states in 2012, demonstrating that pigs are both common and widespread nationwide.
In Sonoma County, wild pigs are concentrated in the north, but Linegar and others say they are moving steadily south towards Petaluma, Sonoma and Carneros, where they were previously rare.
"They're incredibly wily," said J. Hall Cushman, a biology professor at Sonoma State University who has coauthored several studies of the effects of pigs on the landscape. "They're very, very smart and they have been very adaptable at living on their own" in a variety of environments.
There's no firm number on the amount of economic or physical damage pigs do every year in Sonoma County, but farmers and land managers report that pigs are known to tear through fields, looking for nuts, seeds and grubs. They can plow up crops, knock down grape vines and fruit trees and undermine fences.
"I don't know of a fence that could stop a pig coming through it ... you could do a lot of work to keep them out of your property, but it's very, very expensive," said west county rancher Joe Pozzi, former president of the Sonoma County Farm Bureau and district director of the Gold Ridge Resource Conservation District.
In addition to monetary losses, pigs can cause long-term environmental damage, tearing up ground cover, destroying nests of quail and other native animals, and promoting the growth of invasive non-native plants by disturbing the habitat of native species.