Townsend's Ground Squirrel

Description

Townsend's ground squirrel (Urocitellus townsendii) is a species of rodent in the family Sciuridae. It is found in high desert shrublands in several areas of the United States. Although Townsend's ground squirrels occur in arid environments, within those environments they are most common around desert springs and irrigated fields. They also occupy ridgetops, hillsides, and valley bottoms, canal and railroad embankments, and old fields. As a burrowing species, Townsend's ground squirrels select sites with deep, friable, well-drained soils. In southeastern Idaho, 68% of Townsend's ground squirrel burrows were in sand, 28% in silt, and 4% in clay. Townsend's ground squirrels consume mainly green vegetation and some seeds and insects.Green grasses are apparently a staple from late winter until just prior to grass senescence and Townsend ground squirrel estivation, when seeds become the primary diet item. Seeds are an important source of calories just prior to estivation. Where present, winterfat is browsed heavily,but only light browsing of other shrubs has been reported. From March through May on the Arid Land Ecology Reserve in eastern Washington, the Townsend's ground squirrel diet is 49% Sandberg bluegrass, 11% western yarrow (Achillea millefolium var. occidentalis), 8% pinnate tansymustard (Descurania pinnata) seed, 31% other plant species (mostly forbs), and 1% insects. On a big sagebrush-crested wheatgrass community in southeastern Idaho, 80% of Townsend's ground squirrels trapped in June had consumed crested wheatgrass, and Townsend's ground squirrels became dormant after the crested wheatgrass senesced. Cheatgrass (Bromus tectorum) is an important food item in some years. As an annual with wide year-to-year swings in productivity, however, it is not a reliable food source.