Tamias townsendii, Bachman, 1839
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publication ID |
https://doi.org/ 10.5281/zenodo.6840226 |
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DOI |
https://doi.org/10.5281/zenodo.6840619 |
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persistent identifier |
https://treatment.plazi.org/id/064D0660-FF83-ED7E-FF6D-F633F6E8FF59 |
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treatment provided by |
Diego |
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scientific name |
Tamias townsendii |
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Townsend’s Chipmunk
French: Tamia de Townsend / German: Townsend-Backenhornchen / Spanish: Ardilla listada de Townsend
Taxonomy. Tamias townsendii Bachman, 1839 View in CoL ,
“lower Columbia River, near mouth
of Willamette River, Oreg.,”
Multnomah
County, Oregon, USA.
This species is part of the townsendii complex, which includes 7. senex, T. siskiyou, and 7. ochrogenys. Two subspecies recognized.
Subspecies and Distribution.
T: t. cooperi Baird, 1855 — SW of British Columbia (Canada) E of the range of townsendii up to 200 km inland through Washington and Oregon, to the Rogue River in S Oregon (USA).
Descriptive notes. Head—body 139-146-3 mm,tail 110-5-115-9 mm; weight 70-76-1 g. Townsend’s Chipmunk has dark pelage in anterior part of body and grayish in posterior part. Ventral pelage is white to cream and tail has dark hairs with white to gray tips. Nominate fownsendii has a yellowish olive gray to rich yellow brown dorsum, and dark dorsal stripes, which are black to brownish black. Subspecies cooperi is smaller
than townsendii, and has a grayer and lighter pelage and grayer dark dorsal stripes. Chromosome number of Townsend’s Chipmunk is 2n = 38. The 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. Areas of dense underbrush in mesic closed-canopy forests. Townsend’s Chipmunk is more abundant in upland areas, but reproductive individuals are more common in riparian forests, and juveniles are more common in upland habitat. Presence of woody debris appears to be important and affects movement, and possibly survival, of individuals. Population density also increases when herbaceous plants and shrubs dominate after a forest clear-cut; it is known to use riparian buffersafter clear cutting.
Food and Feeding. Diet of Townsend’s Chipmunk consists of seeds, fruits, tubers, leaves, and epigeous and hypogeous fungi, usually from the genus Melanogaster and Rhizopogon based on spore content of feces. The larder usually contains hazelnuts, acorns, and conifer seeds. In South Vancouver Island, it is known to sometimes consume or hoard seeds of lodgepole pine (Pinus contorta, Pinaceae) and white spruce (Picea glauca, Pinaceae) infected with Caloscyphafulgens, which is a fungus that appears to arrest seed germination and may facilitate overwinter storage of seeds. Townsend's Chipmunk may be a disperser of this fungus, but further research is needed to elucidate the relationship between these species.
Breeding. Breeding season of Townsend’s Chipmunk occurs between late April and early May in colder temperate areas, and young emerge from nest during early July, however, some adults can be sexually active through entire summer, with some lactating females being found in early August. Gestation lasts 28 days and average littersize is 3-8 young, each weighing 3-2-3-9 g at birth. At ¢.3 months old, young have an adult appearance, but only reach sexual maturity after the first winter.
Activity patterns. Townsend’s Chipmunk is terrestrial and diurnal, with an activity peak at midday. It can be active year-round on the Pacific coast, but will hibernate in colder regions. In the eastern Cascade Mountains, USA,it can hibernate for up to 4-5 months.
Movements, Home range and Social organization. Average home range size is 0-8 ha and average population density is 0-6-2-6 ind/ha; however, because Townsend’s Chipmunk appears to be a trap prone species, these estimations should be viewed with caution. The Yellow-pine Chipmunk (7. amoenus) is a common sympatric species, but Townsend’s Chipmunk appears to be the dominant of the two.
Status and Conservation. Classified as Least Concern on The IUCN Red List. The current population trend is stable. Townsend’s Chipmunk is considered common in its area of distribution and population densities may actually increase 3-10 yearsafter clear cutting. There are no major threats to Townsend’s Chipmunk at this time, but population numbers of coastal British Columbia declined temporarily after an herbicide treatment of Douglasfir plantations. In the north Pacific coast, Townsend’s Chipmunk, together with the Northern Flying Squirrel (Glaucomys sabrinus) and species of Tamiasciurus, compose a sciurid community that collectively serve as indicators of forest health, with Townsend's Chipmunk being more abundant in mature or primary forests.
Bibliography. Carey (2001), Carey & Wilson (2001), Carey et al. (2002), Cole et al. (1998), Colgan & Claridge (2002), Hammond & Anthony (2006), Hayes et al. (1995), Lidicker (1999), Linzey & NatureServe (Hammerson) (2008z), North et al. (1997), Sutton (1993), Thorington et al. (2012), Waldien et al. (2006).
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
