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Documenting a Changing World

We're documenting how Southern California’s deserts have changed over the last century. Decades after zoologist Joseph Grinnell’s expeditions into California’s wild places in the early 1900s, museum staff returned to Grinnell’s study sites. Along with UC Berkeley’s Museum of Vertebrate Zoology, we retraced his team’s footsteps in the Mojave National Preserve, Joshua Tree National Park, and San Jacinto Mountains to reevaluate the flora and fauna. We compared our extensive data with Grinnell’s specimens, photos, and field notes, revealing significant range extensions, steep declines, and surprising stabilities among various species of animals.  

Searching for the San Bernardino Flying Squirrel

The San Bernardino flying squirrel, a California Subspecies of Special Concern, once glided through the forests of the San Jacinto and San Bernardino mountains. But in recent decades, squirrel sightings in the San Jacinto range have dwindled to zero. To survey these poorly understood animals, The Nat teamed up with research institutions, state agencies, and community members. Together, we detected flying squirrels throughout the San Bernardino mountains, but still turned up zeros in the San Jacinto range, suggesting that suitable squirrel habitat is shrinking. This animal may be a keystone species—one that many other species depend on—and its disappearance from southern California could spell trouble for the forests it calls home.

Understanding How Wildlife Responds to Wildfire

Despite the central role wildfire plays in San Diego’s ecosystems, the ways different animals recover from wildfire is poorly understood. After 2002’s Pines fire and 2003’s Cedar fire, Nat researchers launched an extensive, five-year field survey to find out how local birds and mammals responded. We found a mixture of animal responses—negative, positive, and neutral—and highlighted the species most at risk as the frequency and intensity of fires accelerate. Animals we are especially concerned about include the pygmy nuthatch, white-headed woodpecker, and western grey squirrel. 

Saving the State Amphibian from Extinction

Nat scientists are working to bring the California red-legged frog back from extinction in Southern California, where it disappeared more than 20 years ago. We helped Mexican conservationists build and restore ponds in Baja California to stabilize their populations, then translocated frog eggs from south of the border to San Diego and Riverside Counties. Drought and invasive species are still a threat, but the relocated frogs are doing well. The ponds on both sides of the border were designed with resiliency in mind, and we're adding to their populations each year.

Reducing Ringtail Roadkill

The Nat is working to reconnect the fragmented homeland of one of America’s most elusive mammals. Ringtails are cat-sized, bushy-tailed relatives of raccoons, found in Arizona and Southern California’s rocky wildlands. Unfortunately, much of their habitat in San Diego County is crisscrossed with highways, and many end up as roadkill. In alliance with the San Diego Zoo Wildlife Alliance, Caltrans, and the U.S. Forest Service, we are tracking their movement and behavior so we can connect their habitats with wildlife corridors and reduce car strikes. These animals are fully protected, but poorly understood—no one knows if their populations are shrinking as development continues, but we’re not waiting around to find out.