Somewhere along the ridges of the San Geronimo Valley, a wild animal has just triggered a motion-activated camera. The image, along with a couple million more, is helping researchers to better understand population and migration trends of wildlife across the valley and on Mount Tamalpais.
Some 180 cameras are scattered on a calculated grid throughout the Gary Giacomini and Roy’s Redwoods Open Space Preserves, Samuel P. Taylor and Mount Tamalpais State Parks and Muir Woods National Monument, where they’re capturing candid moments in the lives of mostly mammals (plus a few turkeys and vultures). A cadre of volunteer citizen scientists help catalog the images into a massive online database. For nearly three years, the Marin Wildlife Picture Index Project has been accumulating hard data as part of a project undertaken by five agencies.
The National Park Service, California State Parks, the Golden Gate National Parks Conservancy, Marin County Parks and Open Space District and Marin Municipal Water District are working together as part of the One Tam consortium to measure biodiversity across all of the agencies’ jurisdictions. Three years of data is required before the trends are considered legitimate, a standard set by the international Wildlife Picture Index Project, and this local effort will reach its three-year benchmark in the fall.
Speaking to the Board of Supervisors last week, Lisa Michl, a wildlife biologist with Marin County Parks, presented preliminary findings that showed the county supports a robust wildlife community. The project suggests the county is a source population for the rest of the Bay Area, with animals born here migrating to other parts of the region. Ms. Michl told supervisors that the number of medium-sized carnivores—coyotes, bobcats and other mesocarnivores—is a key indicator of a thriving ecosystem.
“If you have a large, healthy population of medium-sized carnivores, then you know you have enough herbivores to support that population of carnivores—and in turn, enough vegetation to support the herbivores,” she said.
Researchers are also looking at wildlife corridors to study migration patterns. In particular, they are interested in learning whether animals traverse major roadways, especially Sir Francis Drake Boulevard.
The project adheres to an international method first established by the Wildlife Conservation Society and the Zoological Society of London. Similar projects have been deployed in Mongolia, Brazil and Sonoma County.
Marin’s project began in 2014, when 100 cameras were placed on trees or attached to wooden stakes in the Lagunitas Creek watershed. Each worth about $200 and the size of a small birdfeeder, the cameras operate on rechargeable batteries to record photographs onto memory cards. The cameras, which do not emit light, capture three pictures over five seconds once an animal large enough to trigger the sensor has passed before its field of vision.
At least 15 native mammal species—mostly black-tailed deer, gray squirrels, coyotes and small rodents—have been documented so far, along with a hefty collection of blurry park service vehicles and unsuspecting hikers. (The project does not use the photographs for enforcement purposes.)
Every 12 weeks, a biologist returns to retrieve the memory cards and then upload the hordes of images onto a database that uses software donated by Hewlett Packard Enterprises. To help analyze each of the two million photographs captured over the last two and a half years, the project relies on a bevy of volunteers who attend cataloguing workshops offered three times a month. Over 250 volunteers have assisted in logging photos so far.
On a recent Tuesday afternoon at the Marin Municipal Water District’s offices in Corte Madera, a dozen volunteers helped to register species recently photographed in Samuel P. Taylor State Park. They received a tutorial on identifying the mammals (bobcats always have stripes or spots on their legs) and were informed of some of the rarer species they might encounter.
At least two mountain lions have been sighted in the San Geronimo Valley, including a one-eyed cat affectionately dubbed “Blinky.” Researchers are eager to see other rare species like badgers and weasels.
Volunteers spanning the age spectrum sat at rows of computers in the district office’s Mount Tam Room, jovially cataloging thousands of photos. The atmosphere was buoyant (at one point during the tutorial, raccoons were fondly referred to as “trash pandas”) and there was a mix of first-time helpers and longtime volunteers.
Karen Figenshu of Berkeley has been contributing to the project for the last year and a half and is one of a few to observe a mountain lion, captured near Kent Lake.
“It’s very voyeuristic, if you will, and an inside look into literarily our own backyard.” she said. “It’s almost like a treasure hunt: you’re looking and clicking and all of sudden there’s something. I’m the one who’ll freak out if there’s a badger. It’s a window into what they are doing out there, running and catching food. You’re looking into their world.”
The 2017 Mt. Tam Wildlife Symposium, where complete data results from the Wildlife Picture Index Project’s first three years will be shared, takes place from noon to 4 p.m. on Thursday, Oct. 26 at the Marin Art and Garden Center, in Ross. For information and registration, visit onetam.org/2017-wildlife-symposium.