Their small size, black and white stripes, and long tail help distinguish the chipmunks from other ground squirrels. Note, however, that the golden-mantle ground squirrel is often mistaken for a chipmunk but it lacks stripes on the head, is much larger, and has a relatively shorter tail.
There are several species of these small ground squirrels in the western states. See below for examples of tracks, burrows, digs, and scat.
The Townsend (Tamias townsendi) is a forest dweller of western Oregon and Washington. The brightly colored Yellow Pine chipmunk (Tamias amoenus) favors the ponderosa pine, lodgepole pine, and juniper forests of eastern Oregon and Washington and is found east to the Rockies. The Least chipmunk (Tamias minimus) overlaps in range with the Yellow-pine but prefers brushy or rocky areas of coniferous mountain forests. The Allen's (Tamias senex), Siskiyou (Tamias siskiyou), and Red-tailed (Tamias ruficaudus) have limited ranges in our region.
The tracks closely resemble those of tree and ground squirrels, just on a smaller scale. The straddle for chipmunks is 2-3" compared to 3-4" for Douglas (or red) squirrels. Note, however, that the Southern flying squirrel is about the same size.
Townsend chipmunk, Jackson Bottom, Beaverton, OR
Yellow pine chipmunk in fine dust, Indian Heaven, WA
Tracks in snow are uncommon since Chipmunks hibernate, at least in the northern and high elevation portions of their range. They may not lay on enough fat to get them through the winter, however, so they may awake to feed from underground stores or look for plants under the snow.
The entry to chipmunk burrows are quite round and about 1.5" in diameter. One of the most distinctive characteristics of these burrows is the lack of any excavated dirt around the entrance. Biologists suggest that the chipmunk carries dirt away in its mouth and deposits it where it will not draw attention to the hole. The burrow typically drops straight down a couple inches before turning.
Yellow pine chipmunk, Klammath Falls, OR
Yellow pine chipmunk, Juanita Lake, CA
Townsand's chipmunk in sand, Oxbow Park, OR