No score and seven years ago this Western Weekend, West Marin found itself on the alert for an intimidating presence it hadn’t faced since the time of the Civil War. On May 25, 2003, the first bear to roam these hills in more than 130 years was spotted at the hostel off Limantour Road in the Point Reyes National Seashore.

Awakened about 4:30 a.m., hostel manager Bob Baez and assistant manager Greg King found a medium-sized black bear rummaging through a compost bin and pulling trash out of a Dumpster. They watched for about five minutes until the bear wandered off into the brush.

Although Bear Valley in Olema took its name from the abundance of bears that once were found there, Marin County’s last black bears had been trapped and hunted to death by 1869.

In Occidental 40 miles to the north, however, a sloth of black bears had survived. (Odd as it sounds, ‘sloth’ really is the word for a group of bears.) National Seashore rangers assumed the bear at the hostel had wandered south from his sloth in Sonoma County.

This time of year is the mating season for bears, and rangers suspected he was a young male that had been forced to seek new territory when an older male drove him off.

Other reports came in of the bear raiding bird feeders and residential garbage bins around Inverness Park, but soon he headed south. On May 29 and 30, state park rangers spotted the bear on Mount Tamalpais.

He then showed up in the Golden Gate National Recreation Area. On May 31, four campers at Kirby Cove near the Golden Gate Bridge watched as the bear rummaged through their campsite and dragged away food.

At 4:30 a.m. June 1, two long-time residents of the Zen Center in Muir Beach spotted the bear sitting atop a Dumpster. They hadn’t heard about the bear being in the area and could hardly believe what they were seeing.

Evidence of the bear was then found in Muir Woods National Monument, where a maintenance worker discovered several of the park’s 50-gallon garbage cans “destroyed beyond use,” the GGNRA reported.

Officials of the GGNRA, Marin Municipal Water District, and the California Department of Fish and Game began asking residents of areas where the bear had been spotted to store their garbage inside. If it became accustomed to foraging in household garbage, they warned, the bear could become dangerous and would have to be killed.

Fortunately, that did not happen. As mysteriously as it had arrived, the bear disappeared without a trace, and everyone agreed it had probably gone home to Occidental, which is known for hearty dining.

Black bears are fond of grasses, roots, berries, and insects. They also have an appetite for fish and mammals, including carrion, and are quick to develop a taste for human food and garbage. Or so say the experts.