180. Yellow-cheeked Chipmunk Tamias ochrogenys French: Tamia des séquoias / German: Gelbwangen-Backenhornchen / Spanish: Ardilla listada de mejillas amarillas Other common names: Redwood Chipmunk Taxonomy. Eutamias townsendi [sic] ochrogenys Merriam, 1897, “Mendocino, [Men- docino Co.] California.” (USA). This species is part of the townsendii complex, which includes 7: townsendii, T. senex, and 7. siskiyou. Monotypic. Distribution. N coast of California, from the Van Duzen River to S Sonoma County (USA). Descriptive notes. Head-body 147-8-152-5 mm, tail 109-115-1 mm; weight 80-180 g (males) and 80-120 g (females). The Yellow-cheeked Chipmunk can be differentiated from the other species of the townsendii complex by its larger size, darker dorsal coloration, thinner tail, different vocalization, and structure of the genital bones. In southern part ofits distribution, it can be differentiated from the Sonoma Chipmunk (1. sonomae) and from Merriam’s Chipmunk (7. merriami) by its shorter tail, darker pelage, and larger body size. Chromosome number of the Yellow-cheeked Chipmunk is 2n = 38. Karyotype is type B for Tamias and consists offive pairs of metacentric autosomes, six pairs of submetacentric autosomes, seven pairs of acrocentric autosomes, a submetacentric X chromosome, and an acrocentric Y chromosome. Habitat. Coastal redwoods (Sequoia sempervirens, Cupressaceae), especially in moist areas, with thick underbrush. The Yellow-cheeked Chipmunk occurs from sea level to elevations of ¢.1280 m, but not more than ¢.40 km from the coast. Food and Feeding. Based on anecdotal reports, diet consists of the seeds of grasses and shrubs, insects,fruits, including raspberry (Rubus, Rosaceae) and acorns (Quercus Fagaceae), and fungi during late winter and spring. Breeding. Males are able to mate between March and June. One female with four embryos, which measured 43 mm each, was reported in mid-March. Hybridization of the Yellow-cheeked Chipmunk and the Shadow Chipmunk (7. senex) may occur, based on intermediate “chip” vocalizations registered in the south of the Eel River, in Humboldt County. Activity patterns. There is no specific information available for this species, but the Yellow-cheeked Chipmunk is diurnal. Movements, Home range and Social organization. Population density was estimated at 3-8 ind/ha in Mendocino County, California. Although difficult to observe due to thickness of underbrush, it can be recognized by its vocalizations, which are described as low-frequency two-part “chips.” The Yellow-cheeked Chipmunk vocalizations can be differentiated from Townsend’s Chipmunk (7. townsendii) vocalizations by a lower frequency, and differentiated from the other species of the townsendii complex byits distinctive rhythm. Status and Conservation. Classified as Least Concern on The IUCN Red List. The current population trend is stable and the Yellow-cheeked Chipmunk is locally common in many areas. Currently there are no specific threats across its distribution. Because it is restricted to a small geographic area, large scale environmental changes within this area could have an impact. Bibliography. Foley & Nieto (2011), Gannon et al. (1993), Linzey & NatureServe (Hammerson) (2008ae), Nieto & Foley (2009), Thorington et al. (2012).

Published as part of Don E. Wilson, Thomas E. Lacher, Jr & Russell A. Mittermeier, 2016, Sciuridae, pp. 648-837 in Handbook of the Mammals of the World – Volume 6 Lagomorphs and Rodents I, Barcelona :Lynx Edicions on page 790, DOI: 10.5281/zenodo.6840226