March 7, 2001
Open space district traps, kills wild pigs
Board votes to continue program to control spread of wild
Tough, smart, and prolific, the non-native invaders plow
hillsides and muck up streams and wetlands as they advance
"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
"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
"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."
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
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
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,
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
"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
The Zero Population Veterinary Team would then surgically
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."