Tamiasciurus hudsonicus 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Rodentia Sciuridae

Scientific Name: Tamiasciurus hudsonicus (Erxleben, 1777)
Common Name(s):
English Red Squirrel, Mountain Weasel, Mount Graham Red 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 very widespread, common in suitable habitat throughout its range, and there are no major threats.
Previously published Red List assessments:

Geographic Range [top]

Range Description:This species ranges widely in northern North America. It occurs from Alaska in the United States, eastward across Canada and southward to Arizona and New Mexico (in the west) and to extreme northern Georgia (in the east) in the United States. It is introduced to Newfoundland in eastern Canada.
Countries occurrence:
Canada (Alberta, British Columbia, Labrador, Manitoba, New Brunswick, Newfoundland I, Northwest Territories, Nova Scotia, Nunavut, Ontario, Prince Edward I., Québec, Saskatchewan, Yukon); United States (Alaska, Arizona, Colorado, Connecticut, Delaware, District of Columbia, Georgia, Idaho, Illinois, Indiana, Iowa, Kentucky, Maine, Maryland, Massachusetts, Michigan, Minnesota, Montana, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, Wyoming)
Additional data:
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:It is widespread in North America, and abundant in many areas. Densities of up to 7-8 per hectare have been reported.
Current Population Trend:Stable
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:It prefers coniferous and mixed forests, but also occurs in deciduous woodlands, hedgerows, and second-growth areas. It prefers to nest in tree cavities; and also constructs leaf nests and uses ground burrows.

It breeds March-April and June-July in Quebec. Gestation lasts 31-35 days. Some females produce two litters per year; litter size averages 4-5. Some females breed when less than one year old (Lair 1986).

This species is more territorial than most other North American tree squirrels. Some populations in British Columbia are limited by food (acting through effect on reproduction) (Sullivan 1990); but factors such as territorial behaviour may limit populations at high density (Klenner and Krebs 1991).

Diet consists of seeds, conifer cones, nuts, fruits. It occasionally feeds on invertebrates and small vertebrates. Commonly caches, and later consumes, large amounts of food. Usually quite conspicuous throughout the day. Most active two hours after sunrise and before sunset.
Generation Length (years):4

Threats [top]

Major Threat(s): There are no major threats to this species.

Conservation Actions [top]

Conservation Actions: The range of this species includes several 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
  Conservation sites identified:Yes, over entire range
In-Place Species Management
In-Place Education

Bibliography [top]

Hafner, D.J., Yensen, E. and Kirkland, G.L., Jr. 1998. Status survey and conservation action plan - North American Rodents. IUCN/SSC Rodent Specialist Group, Gland, Switzerland.

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

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

Klenner, W. and Krebs, C. J. 1991. Red squirrel population dynamics. I. The effect of supplemental food on demography. Journal of Animal Ecology 60: 961-978.

Lair, H. 1986. Mating seasons and fertility of red squirrels in southern Quebec. Canadian Journal of Zoology 63: 2323-2327.

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. 1998. Tamiasciurus hudsonicus. Mammalian Species 586: 1-9.

Sullivan, T. P. 1990. Demographic responses of small mammal populations to a herbicide application in coastal coniferous forest: population density and resiliency. Canadian Journal of Zoology 68: 874-883.

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 hudsonicus (errata version published in 2017). The IUCN Red List of Threatened Species 2016: e.T42587A115192299. . Downloaded on 27 May 2018.
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