Townsend chipmunk
| Townsend chipmunk | ||||||||||||
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Townsend Chipmunk in Washington Parc in Anacortes |
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| Tamias townsendii | ||||||||||||
| Bachman , 1839 |
The Townsend chipmunk ( Tamias townsendii , Syn .: Neotamias townsendii ) is a type of squirrel from the genus of chipmunks ( Tamias ). It occurs on the Pacific coast in the extreme southwest of Canada and in the American states of Washington and Oregon .
features
The Townsend chipmunk reaches an average head-torso length of about 13.8 to 14.6 centimeters, the tail length is about 11.0 to 11.5 centimeters and the weight is about 70 to 100 grams. The back color of the animals is brown and, as with other species of the genus, there are several dark back stripes on the back, which are separated by light stripes and delimited from the sides of the body. Compared to other very similar chipmunks in the region, the species is slightly larger, the coat color is darker in the back to the trunk area and grayer in the front back area. The back stripes are very dark, the tail is also very dark with white and gray-tipped hair. The underside of the tail is white to cream in color.
distribution
The Townsend chipmunk is found on the Pacific coast in the extreme southwest of British Columbia in Canada and in the American states of Washington and Oregon as far as the Rogue River .
Way of life
Townsend chipmunks live mostly in moderately closed forest areas with lots of undergrowth. The animals and especially the young ones prefer higher altitudes, sexually active animals are more common in river valleys. It mainly lives climbing in the trees and in the undergrowth of the coniferous forests in its area of distribution. In the area of clearings and felling, the stand density increases significantly due to the available herbs and bushes at the clearing edge.
The Townsend chipmunk is diurnal with activity peaks in the middle of the day. The animals feed mainly herbivorous of seeds and fruits, roots and other plant parts. In addition, there are mainly mushrooms, where they look for and eat both underground and above-ground fruiting bodies. According to evaluations of spores in the faeces Melanogaster and Rhizopogon , the most frequently eaten fungi are , with the amount and diversity changing with the age of the forests and forest areas. The population density of the animals is between 0.6 and 1.1 animals per hectare in young forests and increases to three to four times the value in older forest stands. The territories have an average size of 0.8 hectares.
The animals mainly collect acorns and other seeds and set up storage facilities. Especially in the southern area of Vancouver Island it was observed that the Townsend chipmunk very often consumes and stores seeds of the coastal pine ( Pinus contorta ) and the white spruce ( Picea glauca ), which are attacked by the fungus Caloscypha fulgens , which the It hinders seed ripening and rotting, and thus enables long-term storage. At the same time, the gathering activity of the squirrels spreads the fungus, but the actual relationship between the two species has not yet been fully clarified. They spend the winter in hibernation or hibernation , which can last four to five months in the northern and colder regions. In contrast, the animals of the Pacific coastal regions are usually active all year round.
The animals build their nests underground between and under stones, in tree hollows and in older nests of other animals in the branches of the trees. The animals are territorial and they defend their territories aggressively against conspecifics and other chipmunks. The communication takes place primarily to delimit the territories and as high-frequency alarm calls.
The mating season for this species is in spring, depending on the temperatures. In the regions where the animals hibernate, the mating season is late April to May. However, some adult animals are also sexually active later and mate until early summer. The gestation period lasts 28 days, the litter size consists of three to four (3.8) pups on average. These leave the nests in early July, but sometimes the mother animals can be lactating until August and have young in the nest. The young are sexually mature at the age of three months, but the first matings do not take place until the following year.
In the largest part of the distribution area the species occurs sympatric with other squirrel species. Together with the Northern Flying Squirrel ( Glaucomys sabrinus ) and the Commons, American Red Squirrel ( Tamiasciurus hudsonicus ) represents the Townsend-chipmunks an indicator of habitat quality of coniferous forests. These species come together very often in healthy and well-developed primary forests or well-maintained secondary forests before that are characterized by a high seed production. However, this effect is often attributed primarily to the high biomass production of the Pacific forests. The Townsend chipmunk also lives in parts of the distribution area sympatric with the yellow spruce chipmunk ( Tamias amoenus ). Due to the size of the animals, various birds of prey, martens, cats and dogs come into question as predators , so far only three species of Eimeria and botflies ( Cuterebra ) are parasites .
Systematics
The Townsend chipmunk is classified as a separate species within the genus of chipmunks ( Tamias ), which consists of 25 species. The first scientific description comes from the American zoologist John Bachman from 1839, who described it using individuals from the Columbia River near the confluence of the Willamette River in Multnomah County in Oregon. Within the chipmunk group, the Townsend chipmunk, along with most other species, is assigned to the subgenus Neotamias , which is also discussed as an independent genus. The species was named after the American naturalist John Kirk Townsend (1809-1851), who was best known as a collector and taxidermist and was in close contact with John James Audubon .
Within the species, together with the nominate form, two subspecies are distinguished:
- Tamias townsendii townsendii : nominate form; occurs from southern British Columbia to the Rogue River, with the exception of an approximately 200 km wide coastal strip on the Pacific Ocean in Washington and a 100 km wide strip in Oregon, in which Tamias townsendii cooperi occurs. The shape is larger than the coastal shape with a back color that varies from yellowish olive-gray to strong yellow-brown. The back stripes are black or dark brown.
- Tamias townsendii cooperi : occurs from southern British Columbia to the Rogue River in the coastal area to the range of Tamias townsendii townsendii . The shape is smaller than the domestic shape and is grayer and lighter. The back stripes are more gray to gray-black.
Status, threat and protection
The Townsend chipmunk is classified as Least Concern (LC) by the International Union for Conservation of Nature and Natural Resources (IUCN). This is justified by the relatively large distribution area and the regular occurrence; there are no known risks to the existence of the plant. In the coastal area of British Columbia, the population declined, primarily due to the increased use of herbicides in the Douglas fir plantations .
supporting documents
- ↑ a b c d e f g h i j k l m Richard W. Thorington Jr. , John L. Koprowski, Michael A. Steele: Squirrels of the World. Johns Hopkins University Press, Baltimore MD 2012, ISBN 978-1-4214-0469-1 , pp. 346-347 .
- ↑ a b c d Neotamias townsendii in the IUCN Red List of Threatened Species 2015.4. Submitted by: AV Linzey, NatureServe (G. Hammerson), 2008. Retrieved July 3, 2016.
- ↑ a b Tamias (Neotamias) townsendii In: Don E. Wilson , DeeAnn M. Reeder (Ed.): Mammal Species of the World. A taxonomic and geographic Reference. 2 volumes. 3. Edition. Johns Hopkins University Press, Baltimore MD 2005, ISBN 0-8018-8221-4 .
- ↑ a b Dallas A. Sutton : Tamias townsendii. ( Memento of the original from March 15, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Mammalian Species 435, 1993.
- ↑ Bruce D. Patterson, Ryan W. Norris: Towards a uniform nomenclature for ground squirrels: the status of the Holarctic chipmunks. Mammalia 80 (3), May 2016; Pp. 241-251 doi : 10.1515 / mammalia-2015-0004
- ↑ Bo Beolens, Michael Watkins, Michael Grayson: The Eponym Dictionary of Mammals. Johns Hopkins University Press, 2009, ISBN 978-0-8018-9304-9 , p. 416.
literature
- Richard W. Thorington Jr. , John L. Koprowski, Michael A. Steele: Squirrels of the World. Johns Hopkins University Press, Baltimore MD 2012, ISBN 978-1-4214-0469-1 , pp. 346-347 .
- Dallas A. Sutton : Tamias townsendii. Mammalian Species 435, 1993.
Web links
- Neotamias townsendii inthe IUCN Red List of Threatened Species 2015.4. Submitted by: AV Linzey, NatureServe (G. Hammerson), 2008. Retrieved July 3, 2016.