On one sunny morning last week when I was at Brush Lake, I noticed a chipmunk scampering among the rock piles in an area west of the boat ramp road and west of the lake. He was running jerkily and stopping non-discriminately on the rocks pausing only for a minute then continuing his rock hopping.
The Yellow-pine chipmunks, tamias amoenus, are found in Northwestern United States and Southwestern Canada. They occur throughout Idaho. The Yellow-pine chipmunks are small compared to other members of the genus tamias. They measure 7-9 inches long, 2-4 inches tall, 1-2.5 ounces in weight. Females tend to be larger than the males.
These animals have five black, evenly-spaced, longitudinal stripes down the back. The three dorsal stripes extend from shoulder to rump, whereas the two lateral strips extend only to mid-body. The pale stripes are usually white or grayish. Body color varies depending upon subspecies.
This small chipmunk prefers open dry forest or brushy areas to live and they are particularly common along the forest edge in Boundary County. They are opportunistic foragers, feeding primarily on seeds but will eat insects and bird eggs. They use their cheek pouches to carry conifer seeds and other foods to their burrows. They are very busy gathering and storing food during the fall as they are they are too small to hibernate for the full winter and must wake periodically to feed. So it is possible to see them moving around on sunny, warm days in the winter.
Yellow-pine chipmunks are solitary except during the breeding season in late April and early May. They are active from just before sunrise until about a half hour after sunset. The chipmunks return to their burrows during the middle of the day and are rarely seen from mid-morning to mid-afternoon. On cloudy days, or days with light rain, they may be active all day.
Most of a yellow-pine chipmunk’s day is spent foraging or grooming. These animals frequently brush their fur, take dust baths, and wash their faces. Like most chipmunks, yellow-pine chipmunks move with short jerky movements. The tail is held horizontally or erect during running, and swings from side to side as an individual sits. Foraging typically takes place in areas with shade and shrub cover.
Yellow-pine chipmunks enter a state of torpor for about four months during the winter. When in torpor, they emerge every five to seven days to eat seeds stored in various caches. Caches have been recorded to contain up to thousands of items. Yellow-pine chipmunks do not gain a heavy fat layer in winter like most other chipmunks.
Yellow-pine chipmunks are most common in brushy coniferous forests, but can be found in a broad range of habitat types including areas with rocky outcrops, and meadows. Yellow-pine chipmunks require logs, snags, rock crevices, or stumps for nesting, in addition to shrubs and ground litter for cover.
Yellow-pine chipmunks have been known to live up to five years in the wild, but generally they live an average of three years. Young chipmunks have a 30 percent survival rate in the wild. Once they emerge from the den at about six weeks of age, they are easy prey for a variety of predators.
Enjoy Boundary County and all of its beauty and wildlife.