Tamiasciurus douglasii 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Rodentia Sciuridae

Scientific Name: Tamiasciurus douglasii (Bachman, 1839)
Common Name(s):
English Douglas's Squirrel

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2016
Date Assessed: 2016-08-18
Assessor(s): Cassola, F.
Reviewer(s): Amori, G.
Contributor(s): Hammerson, G.A. & Linzey, A.
Listed as Least Concern because it is widespread, common, and there are no major threats.
Previously published Red List assessments:

Geographic Range [top]

Range Description:This species occurs on the Pacific Coast and Sierra Nevada and Cascade ranges of North American, from southwestern British Columbia in Canada, through the Cascade Range of western and central Washington and Oregon, southward along the coast of northern California to San Francisco, and southward through the Sierra Nevadas to south-central California in the United States.
Countries occurrence:
Canada (British Columbia); United States (California, Nevada, Oregon, Washington)
Additional data:
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:This species is considered to be common. Populations fluctuate with variations in food supply. Densities range from 0.2 - 0.5 per hectare.
Current Population Trend:Stable
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:It inhabits coniferous forests, in upper pine belt and in fir, spruce, hemlock forests. It occurs from the Transition to the Hudsonian life zone. In Washington, populations generally were higher in old-growth than in younger forest (Buchanan et al. 1990). Makes nest of vegetation in trees in summer; roosts in tree holes in winter.

Most males are reproductively active from March-May. Females produce one, perhaps two litters per year. Litter of 2-8, usually 4-6, young is born in May-June. Young first venture to the ground in August. Families stay together much of first year.

Predators include bobcats, martens, coyotes, and large owls. In spring it feeds on new shoots of conifers, inner bark and developing needles; in summer, some green vegetation, fruits and berries. In autumn it eats seeds from conifer cones. May also eat tree sap, fungi, and nuts. Stores cones in a log or burrow. Active throughout the year but usually remains in nest during severe weather. Daily activity begins at dawn and ends at sunset.
Generation Length (years):4

Threats [top]

Major Threat(s): There are no major threats to this species throughout its range. It may be locally threatened by deforestation and habitat fragmentation.

Conservation Actions [top]

Conservation Actions: This species is not known to occur in any protected areas.

Errata [top]

Errata reason: This errata assessment has been created because the map was accidentally left out of the version published previously.

Classifications [top]

1. Forest -> 1.1. Forest - Boreal
1. Forest -> 1.4. Forest - Temperate

In-Place Research, Monitoring and Planning
In-Place Land/Water Protection and Management
In-Place Species Management
In-Place Education

Bibliography [top]

Buchanan, J. B., Lundquist, R. W. and Aubry, K. B. 1990. Winter populations of Douglas' squirrels in different-aged Douglas-fir forests. Journal of Wildlife Management 54: 577-581.

IUCN. 2016. The IUCN Red List of Threatened Species. Version 2016-3. Available at: www.iucnredlist.org. (Accessed: 07 December 2016).

IUCN. 2017. The IUCN Red List of Threatened Species. Version 2017-1. Available at: www.iucnredlist.org. (Accessed: 27 April 2017).

Pacifici, M., Santini, L., Di Marco, M., Baisero, D., Francucci, L., Grottolo Marasini, G., Visconti, P. and Rondinini, C. 2013. Generation length for mammals. Nature Conservation 5: 87–94.

Steele, M. A. 1999. Tamiasciurus douglasii. Mammalian Species 630: 1-8.

Wilson, D.E. and Ruff, S. 1999. The Smithsonian Book of North American Mammals. Smithsonian Institution Press, Washington, DC, USA.

Citation: Cassola, F. 2016. Tamiasciurus douglasii. In: (errata version published in 2017). The IUCN Red List of Threatened Species 2016: e.T42586A115192165. . Downloaded on 22 June 2018.
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