Have you ever seen a squirrel fly? For most people, the answer is no. For a small group of GBI Research Associates, the answer is yes – many times! Amidst the swarm of summer hikers and mountain bikers at Lake Tahoe-Nevada State Park, a five-person field crew spent long hours searching for, and gathering data on, northern flying squirrels (Glaucomys sabrinus). You won’t see them very often because they’re nocturnal, only foraging for mushrooms and lichen at night. Most Tahoe locals don’t even know they exist. This summer, we often heard, “I didn’t know we had flying squirrels!” or “Yeah right, and flying monkeys too?”
But really, there are flying squirrels in Nevada. They don’t actually fly, but rather use large flaps of skin between their arms and legs to glide from tree to tree during foraging bouts. Plus, the Carson Range, on the eastern side of Lake Tahoe, is the only place they are known to exist in the entire state! So, you can imagine the need to learn more about this unique, rarely seen species, especially since they are an important part of a healthy forest.
David Catalano, Nevada Dept. of Wildlife (NDOW), had already done some winter reconnaissance in the State Park, and because flying squirrels are active year-round (unlike other rodents that hibernate), he was able to photograph several flying squirrels with remote cameras. Since they are considered a species of conservation concern by NDOW, David collaborated with GBI to conduct a three-year study on flying squirrels to learn more about their habitat use within the park. GBI hired a team of four Research Associates to capture and attach radio-transmitters to flying squirrels in an area of the park called North Canyon. This would allow us to track their movements and learn more about where they spend their time foraging and nesting. As you can imagine, it made for an amazing summer filled with early mornings, furry critters, and spectacular scenery.
We started field work in late spring, when some snow was still on the ground, and spent several weeks putting out rodent live-traps filled with bird seed and peanut butter. By the time we finished trapping, we had attached radio-transmitters to 12 flying squirrels. Radio-transmitters were about the size of a small grape and were attached to squirrels with a small collar that fit around their necks. We many other animals too: four chipmunk species, three other squirrel species, woodrats, mice, Stellar’s jays (oops!), and even a couple of long-tailed weasels (stinky!), but we only put transmitters on flying squirrels. We released them all at the base of trees, and watched them climb to the tops and take flying leaps that will not be soon forgotten. One even glided over 100 meters away!
Once the squirrels had resumed their normal activities, we spent countless hours tracking their movements using telemetry equipment (basically a receiver and a big antenna that could pick up the signal of each squirrel from over half a mile away). We tracked them to the exact tree where they were sleeping, and sometimes we even found more than one flying squirrel in the same tree. During 3 months of telemetry, we collected a wealth of information about flying squirrels in the east basin of Tahoe, including the type and size of nest trees they used, how close they nest to water, how many nest trees they used in one season, and many habitat characteristics. This information will be useful to land managers who are continually making decisions about our public forests.
In a way, it seemed like we had a personal relationship with each squirrel that we studied, and I’m sad to say that two of them were eaten by predators towards the end of the season. But we were still able to locate their collars, and one of them was found in a bobcat den over a mile away from its location the previous night! As sad as it was to lose two individuals, it was good to know that they are filling one of their many roles in nature. They are food for several species around Lake Tahoe, including owls and pine marten, and flying squirrels are considered indicators of a healthy forest. It’s nice to know that we have flying squirrels in our Nevada forests, and even better to know that GBI is involved in research that could make a big difference for flying squirrels and many other sensitive species in the Lake Tahoe area. And next time you’re out hiking, don’t be surprised if you see a squirrel jump out of a tree and never hit the ground.
– Mark Enders, Wildlife Monitoring Specialist, GBI Research Associate Program