Guess what naturalist Ken Lavin got when he organized a hunt for some big, hairy spiders: A crowd!

"I've never been on a tarantula hike before," said Nancy Norland of Danville as she joined nearly 40 participants preparing to scour the brown flanks of Mount Diablo for spiders roughly the size of an orchid corsage.

Fall is the time of year when male tarantulas normally scuttle around the hills in search of mates hiding in burrows. The spiders are common enough to warrant the posting of tarantula crossing signs at the north and south entrances of the 20,000-acre state park.

Tarantulas have "been scaring folks here for ages," Lavin told the group that had assembled at Mitchell Canyon. But he warned, "This is not particularly a good year."

Indeed, during a 3 1/2-hour trek up steep dirt trails to Black Point, the group spotted no tarantulas. Lavin, a guide for the Mount Diablo Interpretive Association, came prepared. He treated his audience to an encounter with a pair of mahogany-colored spiders that he had captured earlier in case there were no sightings.

The captives -- they were slowly scaling the walls of their plastic containers -- weren't exactly an instant sensation. A nervous ripple of laughter traveled through the crowd when Lavin suggested that "we can pass these around and hold them" before letting them go.

Participants seemed to warm up to the eight-legged guests of honor once they heard Lavin's description of the tarantula's life cycle and mostly gentle disposition.

"Oh, he's beautiful," said Norland after letting one of them slowly creep across her hand. "He's so light." 

For 8-year-old Ryan Neil of Danville, the spider's touch was "furry" and not remotely frightening. "It felt like it was just harmless," he said. Ryan's father, Mike, said the promise of a spider hunt was all it took to snare his son and a friend, 8-year-old Miles Dobin, for the Sunday morning trek. "Even if you haven't been an 8-year-old boy, there's a natural appeal, I think," Neil said.

That appeal drew about 400 people earlier this month to an annual tarantula festival at Henry W. Coe State Park in Morgan Hill. A chief goal of the festival was educating the public about creatures that seem to hold a horror, movie-like fascination, said ranger Barry Breckling.

There was a similar message for the Mount Diablo hikers. Tarantulas, Lavin explained, have acquired a sinister reputation that is largely undeserved. "It turns out the tarantula is just about the most innocuous creature on Mount Diablo," he said.

Sightings of the spiders figured prominently in 19th century accounts of trips up the mountain.

A team of geologists returned from a surveying expedition in the early 1860s with wild tales of spiders "the size of small birds," he said. About he same time, copper miners gave whiskey the nickname of "tarantula juice" and claimed the drink was an antidote to the spider's feared bite.

In reality, most spider encounters are far riskier for tarantulas than humans, Lavin explained. "They're very delicate," he cautioned as he picked up one of the captives and let it wander on a picnic table. "It's very easy to drop them. They lose their legs."

Possessing a bite no worse than a bee sting and generally reluctant to attack, tarantulas often fall victim to the underside of hikers' boots and motorists' tires. They also can be eaten alive if attacked by a nasty parasitic wasp that first paralyzes the spider and then lays eggs on its body. The spider's primary defense: tiny, sharp hairs that it flicks off its abdomen. "I fed these guys," Lavin told his audience. "It took them 15 minutes to kill a cricket. It was kind of embarrassing." He had no explanation for the spider's apparent sparse numbers this fall.

Most of the tarantulas roaming around are older males that have molted for the last time and are looking for females buried underground. Perhaps the spider population was reduced by a harsh winter when those males first hatched about seven years ago, Lavin speculated. Male spiders typically 7 to 10 years; females can live to be 20 years old.

Dave Matthews, the park's supervising ranger, said he hadn't noticed a particular drop in the tarantula population, but confessed, "I'm not out counting."

In hopes of protecting the spiders from being squashed under the tires of passing motorists, rangers last year posted warning signs at two main entrances. "We ask people to watch out for them," said Matthews, who noted that visitors aren't allowed to collect spiders or any other creatures in the park without a special permit like the one Lavin had obtained.

While the trek up Mitchell Canyon turned up no tarantulas, the group did spot several burrows. The openings are roughly the size of a nickel and often are covered by a dense netting of web that alerts occupants to the arrival of potential prey -- or suitors.

While spiders were the big draw for the morning outing, some hikers acknowledged that they had other reasons for showing up. "I wanted to be out on a Sunday," said Diablo resident Kay Batts, who started the morning playing the organ at a 7:30 Mass. As for the appeal of hunting for tarantulas, she admitted, "I'm more interested in his ladybug hike. "

By the end of the trek, a few participants who initially feared spiders thought they'd be a bit more charitable toward tarantulas in the future.

"I wouldn't get the broom now," said Carla Riboczi of Concord. "I'd probably let it alone."