Chipmunks look a lot like ground squirrels, and there are 22 different kinds in North America. In California alone there are many different species, all suited to the mountain areas and different ecosytems of California. Every species has a different call. In Michigan, there is the Eastern Chipmunk, and in the Upper Peninsula of Michigan, the Least Chipmunk, so called because it is so tiny. Chipmunks like to scurry around and gather seeds and nuts to store in underground burrows. One time I even saw a chipmunk jumping up to pull down the stalk of a flower that had gone to seed so it could pull out the seeds inside. They are generally not active on rainy, cold, or snowy days. They are able to climb trees well and often do so to get a vantage point, or use a ledge to eat their nuts or seeds on. They do not really hibernate but instead wake up periodically to eat from their stored food. They have three different calls that I have heard: A high pitched “chip” sound, a lower pitched “chuck”, and a sharp whistle. The whistle is more like a surprised noise they make as they run for cover, and sounds sort of like a little chatter. The chip sound is more like a warning call, and possibly the chuck call is more like a territorial dispute between chipmunks. I don’t really know this for sure though, I’ve just picked up these ideas through observing them.