No one's rooting for these pigs

Pinnacles finishing 30-mile hog-proof fence

Michael McCabe, Chronicle Staff Writer

Saturday, December 1, 2001

Pinnacles National Monument, San Benito County -- There are two types of mammals fighting for control of this park, humans and pigs, and the pigs appear to be winning.

Walk through just about any part of this 24,000-acre paradise and you would think an army of Rototillers had run amok.

It's pig created muck -- wild, nonnative pigs rooting for acorns, bugs, roots, whatever is remotely edible, wrecking the land for native species, turning it ugly for humans.

This increasing destruction of the Pinnacles by the omnivorous pigs is driving the completion of what park officials believe will be the longest continuous fence in the United States aimed at keeping porkers out. A kind of Great Wall of the Pinnacles, the nearly 30-mile-long fence will encircle the entire core area of the park.

The carefully engineered fence, generally 36 inches high, consists mostly of barbed and steel wire. Deer, coyotes, raccoons, foxes, bunnies, bobcats and other forest creatures can go through or over it. But pigs can't climb over it and the openings are too small for them to pass through.

"Left on their own, the wild pigs will destroy just about every square inch of this beautiful park," said Tom Leatherman, a National Park Service botanist at Pinnacles as he inspected a newly completed section this week. "But we think this fence will work -- pigs don't jump."

The fence, which costs $40,000 a mile, has been under construction off and on since 1985, with progress interrupted for several years by budget woes and occasional fires. Now, with 26 miles completed, the end is in sight, perhaps by early 2003, park officials say.

Then -- assuming the fence works -- the job will be to figure out how to get rid of the pigs trapped inside. Estimates of their numbers today range from 80 to 500 or more, depending on which week it is and how rainy it's been. With ideal conditions, pigs can produce three litters a year, with each litter numbering two to eight hungry piglets.

For the past several weeks, park officials have been holding public hearings among the locals, soliciting ideas on how to deal with the pig problem. Trap them? Invite hunters in? Leave them be? The written public comment period closes Dec. 15.

"What we have heard so far is that the majority of people want us to do anything and everything we can to get rid of them," said Amy Fesnock, a park biologist for the National Park Service. "We expect to show a dramatic improvement in the park environment if we can stop the rooting."

The park service says it will be ready to make a decision on what to do with the pigs sometime next year, and so far most experts believe trapping -- and shooting -- will be the main weapons. The traps of various sizes would actually be large cages with bait inside. For pigs too trail-wise to wander into traps, the park might hire hunters, or bring in volunteer hunters, aided by dogs, to dispatch them.

Wild pigs, introduced into the region around 1925 for sport hunting, are a match for many dogs, no matter how fierce. Pigs have razor-sharp canines that flare out. A piglet only 6 or 7 months old can weigh 60 to 70 pounds. Some weigh 200 pounds, and the biggest ones get to be 400 pounds or more. An adult pig can often get the upper hand with a dog, sometimes tossing it 10 feet in the air before trotting off at a hasty pace.

The hairy pigs are not just a problem in the Pinnacles, of course. They have become a growing menace in Hawaii, the Channel Islands and Santa Catalina Island, and various private and governmental groups have installed pig fences in those parts as well. Pigs also have invaded the Bay Area, especially in parklands like the East Bay Regional Park District, Midpeninsula Regional Open Space District and the mountainous areas of Santa Cruz County.

"It's a very serious issue," said Joe DiDonato, wildlife program manager for East Bay Regional Parks, where more than 2,000 wild pigs have been killed through eradication programs since 1993 -- and still they keep coming. "We have been looking at the stomach contents of some of the pigs we have killed, and we find them stuffed with acorns. When we go out looking for acorns in the wild we cannot find any at all on the ground."

That presents worrisome implications for the long-range regeneration of California's native oaks, including valley, live and blue oaks. Pigs also adversely affect many native wildlife species -- including deer, squirrel, quail and other birds -- by out-competing them for food, especially acorns. Other native species -- salamanders, frogs, moisture loving plants -- are being pushed out because the pigs' rooting of the soil increases erosion and reduces wetness and nutrients in the soil. All that opens the way for other nonnative species to take over, like the dreaded star thistle.

While no one believes wild pigs can ever be eradicated from California, isolated success can be had with a well-designed fence, experts believe.

"It has been done successfully in the Channel Islands and parts of Kauai, but the key is being very vigilant with the fencing -- fanatical maintenance has to be part of the program," said Dave Garcelon, president of the Institute for Wildlife Studies, based in Arcata, a company that has done large-scale conservation programs all over the globe.

Dick Seever, who runs Rural Pig Management, a firm hired by several Bay Area park districts to trap and kill pigs, said he hopes that Pinnacles National Monument will allow hunters to try their hand for awhile.

"Sport hunting will never eradicate the pigs, but I think it will give the public a chance to see how difficult the problem is," Seever said. "Let the hunters enjoy themselves, even though only trapping them, plus a fence, will reduce them to zero."

E-mail Michael McCabe at mmccabe@sfchronicle.com.

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