|Scientific Name:||Urocitellus mollis|
|Species Authority:||Kennicott, 1863|
Spermophilus mollis Kennicott, 1863
|Taxonomic Source(s):||Helgen, K.M., Cole, F.R.,Helgen, L.E. and Wilson, D.E. 2009. Generic Revision in the Holarctic Ground Squirrel Genus Spermophilus. Journal of Mammalogy 90(2): 270-305.|
|Taxonomic Notes:||Spermophilus canus and S. mollis formerly were included in S. townsendii. Baker et al. (2003) and Thorington and Hoffmann (in Wilson and Reeder 2005) recognized the three taxa as distinct species, noting their distinct cytotypes and lack of hybridization.|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Reviewer(s):||Amori, G. & Chanson, J.S.|
Listed as Least Concern, because it is widespread and common in a major portion of its range, and its populations are not declining fast enough for listing in a more threatened category.
|Previously published Red List assessments:|
|Range Description:||This species occurs in Washington, north of the Yakima River and west of the Columbia River and, disjunctly, in the southeastern corner of Oregon, southern Idaho (Snake River Valley), southward through Nevada (except extreme southern Nevada), extreme east-central California, and western Utah in the United States.|
Native:United States (California, Idaho, Nevada, Oregon, Utah, Washington)
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||It forms colonies of >30 adults/ha. Although densities of 331/ha (adults and juveniles) have been reported, this figure is likely to be an overestimate. Studies showing 3-32 adults/ha (not including juveniles) are likely to be more representative.|
|Current Population Trend:||Unknown|
|Habitat and Ecology:||It is found mainly in high desert (sagebrush, shadscale, greasewood). In southwestern Idaho, highest densities were in winterfat-Sandberg's bluegrass communities, with intermediate densities in big sagebrush-dominated communities and lowest densities in shadscale communities; scarce in communities dominated by exotic annuals (Yensen et al. 1992). It generally occurs in well-drained soils, especially embankments, often around desert springs and irrigated fields. Makes extensive burrow systems. |
Young are born in a nest chamber in an underground burrow. This species breeds late January-early March, depending on locality. Drought may suppress breeding. Gestation lasts 24 days. Litter size typically is 5-10; one litter per year. Males mature as yearlings or as two year-olds; females breed as yearlings (Rickart 1987).
Mean home range was estimated at 1,357 m². May form colonies but families and individuals live separately. Compared to other ground squirrels, it has high fecundity and low adult survivorship and is short-lived (Rickart 1988).
Diet includes herbaceous vegetation (grasses, forbs, and exotic annuals), and seeds; it may also eat some shrub parts and animal matter. Will often feed on crops. May climb bushes while foraging. Emerges from dormancy in late winter or early spring (males before females) but returns to dormancy during May-July, when grasses dry out.
|Major Threat(s):||Habitat conversion to agriculture and rangeland degradation. A decline in the late 1980s in the Snake River Birds of Prey Area in southwestern Idaho was due to widespread conversion of desert shrublands to exotic annual-dominated communities by wildfires (Yensen et al. 1992).|
|Conservation Actions:||This species is not known to occur in any protected areas.|
|Citation:||Hammerson, G.A. 2008. Urocitellus mollis. The IUCN Red List of Threatened Species 2008: e.T42469A10709385.Downloaded on 25 August 2016.|