Hunters and Geo-Gatherers

Hunters and Geo-Gatherers

How high-tech treasure hunting is bringing people—from young families to urban hipsters to seasoned adventure seekers—outside to explore East Bay neighborhoods and parks.

Katie Senser stumbled across her first geocache by accident.

She was picnicking with friends at Bald Rock, a barren, wind-swept expanse of granite overlooking the Feather River outside Oroville north of Sacramento. It’s a quiet, eerie place, where the wind howls mournfully as it whips through the craggy formations and the only evidence of human activity is small depressions in the rock, worn over centuries, where the local Maidu Indians ground acorns into meal. But it soon turned out that Senser, a Chico art student, and her companions weren’t the first visitors this century.

The group hiked to the summit, hoping to find a good spot to settle for lunch. While her friends were distracted by the towering rock formations, Senser spotted a fence lizard darting into a narrow crevice in the stone. She crawled after it, hoping to catch a new pet, but found something entirely different: Someone had wedged a large Tupperware container into the crack.

“I had no idea what it was at first,” says Senser, 23. “I thought a kid had left their box of toys that they had brought to amuse themselves during a picnic or something. It said ‘’ on top but at a glance it didn’t click. I thought it said something about crocheting until one of my friends said, ‘Oh, cool, you found a geocache!’”

Inside, Senser found a heap of random knickknacks: small plastic dinosaurs, spent bullet casings, marbles, and a tiny notebook. The notebook was filled with the dated names and signatures—both real and team aliases like “Flyhigh”—of all the other people who had discovered this hidden treasure.

Senser has since considered setting out to find more of the area’s geocaches.

“I think it would be a fun excuse to go on a hike,” she says. “But I would probably let someone else navigate.”

Finds like Senser’s are becoming more common. Geocaching, the art of finding hidden treasures via a global positioning system (GPS) device, is a growing pastime, one in which highly competitive “power cachers” rub shoulders with weekend hobbyists and even young children. The Bay Area, especially, has become a hotspot, with nearly every mile of real estate concealing several hidden treasures. Some folks are lured by the love of the hunt; others just need an excuse to get away from their desks.


Seek and ye shall find: The world’s number one geocacher Lee van der Bokke (left), with friends Janet Ellis and Don Carpenter, peers through branches on a recent hunt in the hills above the Caldecott Tunnel. Photo by Lori Eanes.

The process is deceptively simple. A geocaching aficionado hides the “cache,” a container that can be as large as a bucket or as small as a pillbox, records its location using a GPS device, and posts the coordinates on one of several websites dedicated to the hobby. Another fan retrieves the coordinates and uses her own GPS device to track down the cache. The coveted container contains nothing of much monetary value; the lucky finder’s tangible reward is usually a couple of small toys like those you might buy at a dollar store. Prize in hand, the finder deposits a trinket of their own for the next hunter and records the find on the paper log. Finders can also post feedback on websites just for cataloging caches.

Geocaching, which relies on GPS—a high-tech method of calculating an object’s latitude and longitude using satellite signals—is barely a decade old, a real 21st-century hobby. In 1978, the U.S. Department of Defense developed GPS for military purposes, scrambling the satellite signals to prevent civilian use of the system. Ultimately, though, GPS appeared to have greater non-military potential—for mapping, surveying, and air traffic control, among other applications—and in 2000, President Bill Clinton issued an order reversing the scrambling protocol. Only a few days later, David Ulmer, an Oregon computer consultant, hid a target in the woods, posted its coordinates to a GPS enthusiasts’ internet newsgroup, and challenged subscribers to join what he termed the “Great American GPS Stash Hunt.”

Ulmer’s big idea immediately caught on; soon dozens of people were also hiding caches and posting coordinates. By 2002, there were approximately 400 caches hidden in the East Bay alone. Today, there are over 200,000. Yet unlike other technology-related obsessions that have swept our culture in recent years, geocaching lures people outside, and compels them to interact with each other. You might even call it a technological remedy to the increasingly isolated, indoor life that many of us lead in the 21st century, a truly compelling reason for kids and adults to turn their backs on video games and the internet, and venture into the great outdoors.

“Many of the geocachers I know love that it brings us to so many interesting places that we would never have found otherwise,” says San Jose geocacher Jeanne Dittman. “I never knew so many wonderful parks and unique places existed. Since I started geocaching, I have done more walking, hiking, biking, kayaking, and climbing trees than I ever did as a kid.”


Techno-trek: Robert Harvey and Warren Hewerdine (right), co-creators of the Geomate.jr GPS device, search for a cache in Golden Gate Park with colleague Joanna Vaughn. Photo by Lori Eanes.

Cachers in our technologically-oriented region, experts say, take the hobby more seriously than those in many other parts of the country. In the early days, geocaching was an esoteric, rather geeky activity, flourishing primarily around institutions with strong geography departments, such as Stanford University and U.C. Berkeley. Few people other than surveying professors owned handheld GPS devices. That academic focus, coupled with the appeal of the hobby to techie types in Silicon Valley and elsewhere, fostered a highly competitive climate.

“Here in the Bay Area we hold people to a higher standard,” claims David Tabuchi, 48, an ardent geocacher from Pleasanton. Tabuchi and his wife are “power cachers” who have geocached across the country and found over 20,000 caches. On a single day trip, the couple often seeks out up to 50 sites. The cache that Katie Senser stumbled across in an Oroville rock crevice—more or less in plain sight—might, Tabuchi suggests, have received a lukewarm review had it been hidden in an equally obvious spot in Tilden Park or Coyote Hills.

“We’re all a little more critical in our logs about the cache hides,” he continues. “The hides tend to be a little more creative here. A beginning cacher might think it’s fun to throw a Tupperware box into a bush and call that a decent hide. If you try that in Oregon, people will usually be polite and just respond [online] saying it was a ‘good hunt.’ But if you try that in the Bay [Area], you’ll get some honest opinions.”

Conversely, veteran cachers hold a deep respect for people who know how to hide a cache in plain sight, so that it blends flawlessly into its environment. Alamo resident Lee van der Bokke, 56, a retired telecommunications manager—ranked as the world’s number one geocacher, with over 37,700 finds—says that he has “been really been surprised at [the] size and variety of caches.” The lure, he says, “is the challenge of putting my head in the head of the person who hid it.”

Top to bottom: The Geomate.jr; Joanna Vaughn and Warren Hewerdine on the prowl; geocache trinkets; a cache nestled in an East Bay hills tree trunk; a handwritten signature log found inside a cache. Photos by Lori Eanes.

Van der Bokke began hunting seven years ago, thinking that it would be a good excuse to go hiking, but quickly became obsessed. Today, he dedicates at least two full days every week to the hunt. During a cross-country expedition in 2007, he found caches in every state.

He’s seen caches hidden inside bolts on roadside guard rails (a hider will sometimes drill out the bolt, place the cache inside, and replace the bolt). He’s seen others stashed beneath fake dog droppings. One of the most elaborate had been placed in an underground pipe, with the entrance concealed by a shellacked cow pie. The cache would have been easily found by anyone willing to take a chance and lift the pie, but most seekers passed by without ever guessing its secret.


Every day, as you go about your business—parking your car, walking your dog, going on a run—you probably pass dozens of camouflaged geocaches. “I see someone sitting on a bench and they don’t know that there’s something hidden on the bench right under them,” says Joanna Vaughn of Oakland. Up until a year ago, Vaughn wouldn’t have known, either. But since taking a job as a marketing assistant with Apisphere, the Berkeley company that produces the Geomate.jr GPS device for kids, Vaughn has found herself caught up in the craze. “It’s a thrill finding something that’s hidden and not many people know about,” she says.

And, she says, there’s a strong educational aspect to the hobby, too. In downtown Oakland, Vaughn found a cache just outside the National Energy Research Scientific Computing Center in Oakland—which, she learned that day, houses the world’s largest computer. On other treasure hunts, she became familiar with winding side streets in old Oakland, forgotten thoroughfares that were once the hub of the city. And once, following a GPS signal to the top of the parking garage at Oakland’s Kaiser Center, she stumbled across a secret Japanese garden. “If I hadn’t been geocaching, I wouldn’t know about it,” she says.

On a Thursday morning in December, Vaughn is at the corner of College and Ashby Avenues in Berkeley with colleague Warren Hewerdine, the co-inventor of Geomate.jr, and Apisphere’s senior marketing director. Wrapped in scarves and heavy jackets, they’re ready for a day outside, playing hide-and-seek.

The street is bustling early on this chilly weekday morning. Students and shoppers hurry down the street, backpacks slung over shoulders, coffee cups grasped in gloved hands. Few appear to register the two people standing under the awning of the Beanery coffee cafe, each staring intently at a small green plastic gadget.

Popular GPS devices are manufactured by companies including Garmin, Magellan, and Lowrance, but the kid-friendly Geomate.jr—about $70—comes preloaded with the coordinates of roughly 250,000 geocaches around the United States, yet requires only two buttons to operate. When Vaughn presses the “on” button, the device automatically displays a list of the 20 closest hides, and a spinning arrow on the screen points the pair toward their quarry. Vaughn and Hewerdine start down the street, stealing occasional glances at their high-tech toys.

The Geomate.jr leads them behind Espresso Roma and down to the end of a cul-de-sac a block away. But once the duo tracks the cache within six feet, the arrow starts to spin. This is as close as you can get with GPS. Now it’s up to them to figure out where the treasure might be.

A “No Parking” sign warns drivers against stopping here where the street loops back on itself; a tangle of weeds and shrubs has grown up around the base of the sign. “That’s the most likely hiding place,” says Vaughn, gesturing at the patch of green. She and Hewerdine proceed to paw through the brush, searching.

In the urban areas of the East Bay, caches tend to be small. Often, they are magnetically attached to street signs or newspaper kiosks. In this case, Vaughn spots a tiny magnetic cube, about one square inch in size, clinging to the metal post of the street sign. Walking past, you’d easily mistake it for an electrical box—if, that is, you noticed it at all. Inside, there’s just enough room for a pencil stub and a rolled-up sheet of paper for the pair to sign, plus a single Guatemalan coin—Vaughn and Hewerdine’s grand prize.

Spurred by this victory, neither partner is ready to call it a day just yet. The game beckons. The next closest cache, the GPS device informs them, is larger than this one—but it’s also a tougher hide. Undeterred, they stride up Claremont Avenue, leaving behind the busy shopping district for the more subdued residential quarter, following the Geomate.jr’s lead. The sidewalk runs past a small secluded greenway, a brushy square of grass with a wooden bench and several trees. The on-screen arrow points into the foliage; the cache is somewhere in the park.

Hewerdine has been at this long enough to recognize likely hiding spots—a wooden bench along the pathway, an old oak tree covered in ivy. He kicks around in the underbrush until he hits something: a plastic pill bottle. This second cache contains the requisite pencil and paper, as well as a couple of plastic soldiers, and a page of information about geocaching. That way, if someone finds the bottle by accident, they’ll know what it is.

For most geocachers, the trinkets in a cache aren’t nearly as important as the hunt, but a few knickknacks have significance. Some cachers leave specific “calling cards” like small glass fish or rubber frogs. Some finds, too, contain “travel bugs,” trackable tags to attach to cache prizes. When a cacher finds a travel bug, they appropriate it, hide it somewhere new, and log the event online. The process creates an ongoing story, as each person to discover and move the bug adds their story.

Across the street, a flight of concrete stairs ascends the hill, disappearing into the space between houses. The searchers trudge upward in pursuit of yet another cache, pausing to examine a crooked tree hanging over the path and briefly debate which it produces—grapefruit or oranges.

The GPS finally leads them to another cul-de-sac, this one ringed with stately Victorians and wooden bungalows. For obvious reasons, geocaching etiquette forbids hiding caches on private property, so Hewerdine and Vaughn conclude it must be hidden in the row of bushes outside the gate of the closest home.

But after 10 minutes of searching, they haven’t found a thing. This cache seems to have vanished. Disappointment is par for the course: Sometimes a cache is too well-hidden, sometimes the coordinates provided by the hider are off—and sometimes someone has absconded with the treasure. Even so, it’s far from a failed expedition.

“The cache at the end isn’t the only point,” says Hewerdine. “A lot of the fun is just getting there.”


Hewerdine, who grew up in Australia near an open expanse of untouched wilderness, was inspired to create the Geomate.jr after reading Richard Louv’s 2005 bestseller, Last Child in the Woods: Saving Our Children from Nature-Deficit Disorder. Too many children today grow up without contact with nature, Louv notes in his book; they’re trapped indoors watching TV, playing video games, and surfing the internet. A generation deprived of outdoor exploration, he argues, can’t grow to become wise stewards of nature if they never learn why nature has value to them.

“If kids aren’t outside, they grow up with no appreciation for [the] outdoors,” Hewerdine says, echoing Louv. “Our generation typically has memories of going out to the park, playing in creeks, building forts.” Ironically, though, today’s parents—busy, fearful, or both—are often the main obstacle to getting kids out of the house, according to Hewerdine. Even those who want their children to have an active lifestyle, he says, are more likely to encourage indoor activities, like working out with Wii Fit, an interactive computer game that offers programs like canoeing and baseball. In designing the Geomate.jr, Hewerdine knew it was essential to appeal to parents as well as to kids.

And, in fact, no matter what technology they use, many families report that geocaching has brought them closer together, and even spawned greater creativity. Palo Alto map enthusiast Di-Ann Eisnor—a longtime fan of urban exploration—says that her kids, 5 and 8, enjoy inventing stories about the tokens they find inside caches, and speculating about the people that placed them there.

“On the way to the Lego exhibit at the Museum of American Heritage in Palo Alto, we stopped by a cache we check in on from time to time,” says Eisnor. “We found two arcade tokens. The kids remembered we had two [similar] tokens left over from seeing A Christmas Carol and we wondered if maybe [their father] had put them in the cache. We took them and left a few New Israeli Shekels. [But] when we got home we saw that our tokens were still there.” Five-year-old Tabor Eisnor’s revised theory: “They came from Africa.”

Christina Mitchell, 45, says her kids—teenagers Jordan and Kelsey, and 3-year-old Olivia—have a blast teaming up to find treasures. “Even little Olivia gets in on the action,” says Mitchell, a Napa publicist. “The older kids help her by pointing out where it is and then let her open it and place an item inside.”

Kelsey, 12, enjoyed pondering what small, inexpensive signature item best symbolized their family. Eventually, recalling her hometown’s reputation for fine wines, she hit on the idea of leaving behind a wine cork. “It is a great experience for our family,” says Mitchell. “My son likes to play video games—as most boys do—and was not really interested at first. But after finding the first one, he was hooked!”


Veteran geocachers express mixed feelings about the hobby’s increasing popularity and the recent influx of new enthusiasts. Serious cachers often compete for “first-to-find” bragging rights—being the first person ever to find a new cache—and are resentful when fly-by-night newbies snap up those finds first.

“Although it’s great that there are many new cachers, I personally have lost the sense of accomplishment I felt when clearing out an area,” says Lee van der Bokke. “Even if I do clean an area, there are more caches the next day, so it’s a bit frustrating.” Then, too, he notes, “Competition for ‘first-to-find’ has gotten brutal. And that is also frustrating given that many of us keep our stats on that accomplishment. Many of these newer cachers that start out with great enthusiasm, lose it after a while and those stats just go away.”

At the same time, the sport’s increasing popularity has also heightened the stakes. As more and more neophytes start hiding their own caches, the nature of the search is shifting. One rule of geocaching states that caches must be at least 528 feet apart. In a highly saturated area like the East Bay, that means that people have to come up with some very inventive hiding spots—a compelling challenge for pros and amateurs alike.

Once hooked on geocaching, though, the habit is hard to break. The simple game of hide-and-seek speaks to something very primal in our nature: the need to explore, to investigate, to learn. The cache provides a goal, but it’s the journey—the thrill of discovering something new, the triumph of solving a tricky puzzle—that gives the pursuit meaning. Geocaching makes good on the promise of every child’s imagination: There’s treasure everywhere.

Websites devoted to the popular hobby of geocaching include and

Mike Rosen-Molina is an East Bay writer and frequent contributor to The Monthly. His work has also appeared in the East Bay ExpressSacramento News and Review, and PBS Mediashift. He blogs at

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