Last week as I was leading a group of adults on a fall color hike, our collective gaze turned quickly from the canopy of coppers and golds to the forest floor as we watched the flurry of chipmunk mischief unfold. We huddled around, marveling at the energy of these charming rodents.

What drew our attention was not what we saw, but what we heard—their “chips” and “clucks” along with the crunch of dry leaves as two eastern chipmunks (Tamias striatus) scolded and chased each other to protect their precious seed stashes. This obsessive urge to stockpile food overcomes eastern chipmunks each fall. Chipmunks have been known to cram up to a bushel (roughly eight dry gallons) of acorns, hickory nuts and corn into side chambers of their underground burrows. These excavated tunnels can reach up to 10 feet in length.

A chipmunk’s elastic cheek pouches act as grocery bags in this gathering bonanza, bulging with up to 70 sunflower seeds at a time and stretching as large as the chipmunk’s own head. Such a bounty must be collected before the winter winds whip through the woods. Once winter arrives in Lake County, the solitary chipmunk will hunker down in its burrow to doze on and off in a state of torpor, snacking his way through the long, cold months.

Autumn is also a time for home improvement for the eastern chipmunk. A single chipmunk becomes an entire construction crew when creating and rearranging its burrow. The chipmunk excavates a central chamber and multiple side chambers using its teeth and paws, bulldozing dirt with its nose and clearing away the debris in order to hide the entrance from predators. In addition to its hoard of food, a chipmunk creates a cozy nest of chewed leaves and grasses where it will bed down each evening. By sunrise, chipmunks are up and out of their burrows, chattering away. A chorus of chipmunks can be heard in the fall, each critter striking a different tone and adding to a cacophony of “chips.”

Come spring, we will not be the only ones listening to the chipmunk chorus. Researchers have discovered that some ground-nesting birds are listening, too. In his research highlighted recently in the BBC Nature News, PhD student Quinn Emmering states scientists have “…found that by eavesdropping on chipmunk calls, the birds can identify hotspots of chipmunk activity on their breeding grounds, avoid these areas and nest instead in relatively chipmunk-free spots.”

Visit your favorite Lake County Forest Preserve that features woodlands or take the Hike Lake County Challenge, and spend a few moments listening. This time of year, visitors are bound to come across the percussive melody of this rodent hard at work in the rustling leaves.