Yellow-pine chipmunks are common in meadows, rocky outcrops, and the borders of yellow pine and juniper forests. They feed in open, sunny areas, favoring seeds, and use their cheek pouches to carry food to the nest to store for winter. One food cache weighed 190 g—as much as four chipmunks. The chipmunks spend 4-5 months in their winter nests, which are located underground or in rock crevices, waking to feed from time to time. They breed soon after they emerge in the spring, usually in April, and have litters about a month later. When the young first emerge from the nest, they are easy prey for hawks, weasels, bobcats, and coyotes. Those that survive—sometimes as few as 30 percent—continue nursing until August.

Links:
Mammal Species of the World
Click here for The American Society of Mammalogists species account