March 7, 2001

Marion Softky
Staff Writer

Open space district traps, kills wild pigs

Board votes to continue program to control spread of wild pigs

Tough, smart, and prolific, the non-native invaders plow hillsides and muck up streams and wetlands as they advance northward.

"Do pigs eat endangered wildlife? Do they eat red-legged frogs?" asked Deane Little, a board member of the Midpeninsula Regional Open Space District, at a recent special meeting devoted to the pig-control program.

"Absolutely. They're omnivorous," replied Doug Updike, a biologist with the California Department of Fish and Game (CDF).

To protect open space preserves from more damage, the district board voted unanimously to continue its three-year trial program to control feral pigs. It authorized $35,000 to hire Land Management and Resource Company to trap and kill 150 more pigs.

That works out to about $230 per pig, said Jodi Isaacs, a resource specialist with the district. Trapper Dick Seever got $200 per pig for the first seven months of the program, when he trapped and shot 81 pigs on the Long Ridge Open Space Preserve, west of Skyline Boulevard and south of Page Mill Road.

The board also authorized $8,000 for further research on the impacts of the pigs on the local environment, and asked the staff to pursue state and private grants to support further research. The board particularly asked the staff to continue to explore more humane methods of controlling pig populations that don't involve killing them.

"Can we put pigs on the pill?" Director Little asked.

Not yet, replied the experts. Even if there is one, you have to catch the animals first, and you would probably have to repeat the process every year.

One thing everybody agreed on: Pigs are here to stay -- you can't get rid of all of them. The district's goal is to reduce the population to an acceptable level, then maintain them at that level, Ms. Isaacs said. "Our objective is a 70 percent reduction in rooted area in five years."

Alien invasion

Pigs are just one of many non-native species invading California and affecting its biodiversity, Mr. Updike said. "Most non-natives don't play by the rules. They bring a gun to the knife fight, and they often win."

Feral domestic pigs, for example, have been living wild in California since they got loose from Europeans in the 1500s, and Russian wild boars since they were introduced in the 1920s, Mr. Updike said. The two strains have hybridized, creating the mix that is still expanding.

In the mid-1960s pigs were found in 10 California counties. "Now there are wild pigs in 56 of California's 58 counties," he said. Pigs are also extremely fertile. While females can produce two litters a year of up to 10 to 12 piglets, they tend to adjust their reproduction to match the amount of food available, Ms. Isaacs said.

Mr. Updike reported that studies of pig rooting in Salt Point Park in Sonoma County showed that -- on balance -- rooting damaged grasslands. "They work just like a rototiller," he said.

Eva Spitz Blum of Skyline reported that pigs rooting on her 600 acres had brought on an invasion of yellow star thistle, another damaging invader. "Star thistle is increasing exponentially," she said.

Interest in controlling pigs is running so high in the south Skyline area that 28 people attended a recent trapping demonstration, Dick Schwind reported.

Ms. Isaacs' report analyzed 10 alternatives for controlling pigs. All were more expensive than trapping and shooting; all had other serious drawbacks. Doing nothing could lead to the pig population's doubling every six months.

Introducing mountain lions, the only known predator, is impractical. Public hunting on district lands is illegal. And pigs can't be relocated because nobody wants them.

Ms. Isaacs recommended fencing sensitive areas like ponds to keep pigs out. But fencing is too expensive to protect large areas, she noted.

Little Blue alternative

Board members were most interested in a proposal from Mary Paglieri, of Little Blue Society, that might stabilize the pig population without killing them.

Ms. Paglieri, who helped discourage some aggressive coyotes in Portola Valley Ranch last summer, is proposing a $15,000 program for sterilizing -- then releasing -- animals to cut down their breeding rate.

"We're on very new ground," she said. "We'll do scientific studies. We will see the benefit over five to 10 years."

Ms. Paglieri based her proposal on a program that got rid of feral cats at Pete's Harbor in Redwood City. By sterilizing, then releasing, the cats, her team reduced the population from 60 to eight in two years.

Ms. Paglieri proposes working with a veterinary team from the University of California at Davis to control the problem. Under her proposal, 40 adult pigs would be captured and held, a few at a time.

The Zero Population Veterinary Team would then surgically sterilize them.

The staff and experts found formidable logistical problems with the proposal. Capturing and handling large wild pigs in remote locations while veterinarians drive down from Davis, then keeping them until they recover, would be very difficult, Ms. Isaacs said.

Trapper Dick Seever was more blunt. Once you see a pig in a trap, you don't mess with them, he said. "You don't know what you're talking about."

Jim Nee, an agricultural inspector for Santa Cruz County who has been working on pig problems there for 12 years, warned that controlling pigs by killing them doesn't work. "It's got to be in perpetuity," he said. "It's a waste of time and money."