Tamiasciurus hudsonicus - (Erxleben, 1777)
Red Squirrel
Other English Common Names: red squirrel
Taxonomic Status: Accepted
Related ITIS Name(s): Tamiasciurus hudsonicus (Erxleben, 1777) (TSN 180166)
French Common Names: écureuil roux
Unique Identifier: ELEMENT_GLOBAL.2.104800
Element Code: AMAFB08010
Informal Taxonomy: Animals, Vertebrates - Mammals - Rodents
Kingdom Phylum Class Order Family Genus
Animalia Craniata Mammalia Rodentia Sciuridae Tamiasciurus
Genus Size: B - Very small genus (2-5 species)
Check this box to expand all report sections:
Concept Reference
Concept Reference: Wilson, D. E., and D. M. Reeder (editors). 1993. Mammal species of the world: a taxonomic and geographic reference. Second edition. Smithsonian Institution Press, Washington, DC. xviii + 1206 pp. Available online at: http://www.nmnh.si.edu/msw/.
Concept Reference Code: B93WIL01NAUS
Name Used in Concept Reference: Tamiasciurus hudsonicus
Taxonomic Comments: Based on patterns of genetic variation and morphology, Arbogast et al. (2001) suggested that Tamiasciurus should be regarded as comprising one species with three subspecies (hudsonicus, douglasii [including mearnsi], and mogollonensis); mogollonensis represents a southwestern clade that occurs in Arizona, New Mexico, and adjacent parts of southern Colorado and southeastern Utah. Alternatively, Arbogast et al. (2001) suggested that these three taxa might be recognized as separate phylogenetic species. Pending further support for this rearrangement, the North American mammal checklist by Baker et al. (2003) did not accept Arbogast et al.'s (2001) proposed reorganization of Tamiasciurus as a single species. Thorington and Hoffmann (in Wilson and Reeder 2005) also recognized douglasii, hudsonicus, and mearnsi as distinct species.

Earlier, Hall (1981) had suggested that T. douglasii and T. hudsonicus might be conspecific, but Lindsay (1982) concluded that apparent hybrids probably were examples of character convergence.
Conservation Status

NatureServe Status

Global Status: G5
Global Status Last Reviewed: 05Apr2016
Global Status Last Changed: 06Nov1996
Ranking Methodology Used: Ranked by inspection
Rounded Global Status: G5 - Secure
Reasons: Widespread in North America; abundant in many areas.
Nation: United States
National Status: N5 (05Sep1996)
Nation: Canada
National Status: N5 (21Feb2016)

U.S. & Canada State/Province Status
Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
United States Alaska (S5), Arizona (S5), Colorado (S5), Connecticut (S5), Delaware (S3), District of Columbia (SH), Georgia (S3), Idaho (S5), Illinois (S3), Indiana (S4), Iowa (S3), Maine (S5), Maryland (S5), Massachusetts (S5), Michigan (S5), Minnesota (SNR), Montana (S5), Navajo Nation (S5), New Hampshire (S5), New Jersey (S4), New Mexico (S5), New York (S5), North Carolina (S4), North Dakota (SNR), Ohio (SNR), Oregon (S4?), Pennsylvania (S5), Rhode Island (S5), South Carolina (S3?), South Dakota (S5), Tennessee (S4S5), Utah (S5), Vermont (S5), Virginia (S5), Washington (S5), West Virginia (S5), Wisconsin (S5), Wyoming (S5)
Canada Alberta (S5), British Columbia (S5), Labrador (S5), Manitoba (S5), New Brunswick (S5), Newfoundland Island (SNA), Northwest Territories (S5), Nova Scotia (S5), Nunavut (S5), Ontario (S5), Prince Edward Island (S5), Quebec (S5), Saskatchewan (S5), Yukon Territory (S5)

Other Statuses

Implied Status under the U.S. Endangered Species Act (USESA): PS
Comments on USESA: Subspecies grahamensis of southeastern Arizona is listed by USFWS as Endangered.
IUCN Red List Category: LC - Least concern

NatureServe Global Conservation Status Factors

Range Extent: >2,500,000 square km (greater than 1,000,000 square miles)
Range Extent Comments: Alaska to Newfoundland, south to the southern Appalachians and through the Rocky Mountains to Arizona and New Mexico.

Other NatureServe Conservation Status Information

Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) Alaska to Newfoundland, south to the southern Appalachians and through the Rocky Mountains to Arizona and New Mexico.

U.S. States and Canadian Provinces

Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
Color legend for Distribution Map
Endemism: occurs (regularly, as a native taxon) in multiple nations

U.S. & Canada State/Province Distribution
United States AK, AZ, CO, CT, DC, DE, GA, IA, ID, IL, IN, MA, MD, ME, MI, MN, MT, NC, ND, NH, NJ, NM, NN, NY, OH, OR, PA, RI, SC, SD, TN, UT, VA, VT, WA, WI, WV, WY
Canada AB, BCnative and exotic, LB, MB, NB, NFexotic, NS, NT, NU, ON, PE, QC, SK, YT

Range Map
Note: Range depicted for New World only. The scale of the maps may cause narrow coastal ranges or ranges on small islands not to appear. Not all vagrant or small disjunct occurrences are depicted. For migratory birds, some individuals occur outside of the passage migrant range depicted. For information on how to obtain shapefiles of species ranges see our Species Mapping pages at www.natureserve.org/conservation-tools/data-maps-tools.

Range Map Compilers: Sechrest, 2002

U.S. Distribution by County Help
State County Name (FIPS Code)
AZ Apache (04001)*, Graham (04009)
CT New London (09011)*
GA Fannin (13111), Habersham (13137), Murray (13213), Rabun (13241)*, Towns (13281), Union (13291), White (13311)
IA Hancock (19081), Winnebago (19189)
SC Greenville (45045), Oconee (45073)*, Pickens (45077)
WY Big Horn (56003), Crook (56011), Johnson (56019), Sheridan (56033), Washakie (56043), Weston (56045)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
01 Shetucket (01100002)+*, Thames (01100003)+*
03 Saluda (03050109)+, Seneca (03060101)+, Tugaloo (03060102)+, Upper Chattahoochee (03130001)+, Conasauga (03150101)+
06 Upper Little Tennessee (06010202)+*, Hiwassee (06020002)+, Ocoee (06020003)+
07 Winnebago (07080203)+
10 Nowood (10080008)+, Big Horn Lake (10080010)+, Little Bighorn (10080016)+, Upper Tongue (10090101)+, Middle Fork Powder (10090201)+, Crazy Woman (10090205)+, Clear (10090206)+, Beaver (10120107)+, Upper Belle Fourche (10120201)+, Lower Belle Fourche (10120202)+, Redwater (10120203)+
14 Middle San Juan (14080105)+*, Chaco (14080106)+*, Chinle (14080204)+*
15 Upper Gila-San Carlos Reservoir (15040005)+, Willcox Playa (15050201)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
Reproduction Comments: Breeds March-April and June-July in Quebec. Gestation lasts 31-35 days (Lair 1985). Some females produce 2 litters/year; litter size averages 4-5. Some females breed when less than one year old (Lair 1986).
Ecology Comments: Densities range from about 1 per 3.2 ha (Pinaleno Mountains, southeastern Arizona) to 1 per 0.2 ha (Layne 1954, USFWS 1987).

More territorial than most other North Amerian tree squirrels. Some populations in British Columbia are limited by food (acting through effect on reproduction) (Sullivan 1990; see also J. Mamm. 73:930-936); but factors such as territorial behavior may limit populations at high density (Klenner and Krebs 1991, Klenner 1991).

Sciurid mycophagy may play important role in forest ecology (Maser and Maser 1988).

Habitat Type: Terrestrial
Non-Migrant: Y
Locally Migrant: N
Long Distance Migrant: N
Mobility and Migration Comments: Home range varies from 1-6 acres (Banfield 1974). In Alberta, most young settled close to mother's territory (maximum of 323 m from natal territory); of 219 births, only 20 offspring survived to the following spring (Larsen and Boutin 1994). In Minnesota, median dispersal distance for 8 young was 100 m, with 4 remaining in their natal ranges and 4 dispersing away (Sun 1997). In British Columbia, almost all juveniles settled on or adjacent to their natal territory (Haughland and Larsen 2004).
Palustrine Habitat(s): FORESTED WETLAND, Riparian
Terrestrial Habitat(s): Forest - Conifer, Forest - Mixed
Special Habitat Factors: Standing snag/hollow tree
Habitat Comments: Prefers coniferous and mixed forests, but also occurs in deciduous woodlots, hedgerows, second-growth areas. Prefers to nest in tree cavities; also constructs leaf nests and uses ground burrows.
Adult Food Habits: Frugivore, Granivore
Immature Food Habits: Frugivore, Granivore
Food Comments: Diet consists of seeds, conifer cones, nuts, fruits. Occasionally feeds on invertebrates and small vertebrates. Commonly caches, and later consumes, large amounts of food; characterized by larderhoarding in the west, scatterhoarding in the east (Dempsey and Keppie, 1993, J. Mamm. 74:1007-1013). Also taps maple trees and consumes sugar residues (Heinrich, 1992, J. Mamm. 73:51-54).
Adult Phenology: Crepuscular, Diurnal
Immature Phenology: Crepuscular, Diurnal
Phenology Comments: Usually quite conspicuous throughout the day. Most active 2 hours after sunrise and before sunset.
Length: 39 centimeters
Weight: 252 grams
Economic Attributes Not yet assessed
Management Summary
Monitoring Requirements: See Halvorson (1972) for information on handling techniques and devices.
Population/Occurrence Delineation
Group Name: Tree Squirrels

Use Class: Not applicable
Minimum Criteria for an Occurrence: Evidence of historical presence, or current and likely recurring presence, at a given location. Such evidence minimally includes collection or reliable observation and documentation of one or more individuals in appropriate habitat where the species is presumed to be established and breeding.
Separation Barriers: Major water barriers in regions where water does not regularly freeze in winter; greater than 200 meters wide.
Separation Distance for Unsuitable Habitat: 2 km
Separation Distance for Suitable Habitat: 5 km
Separation Justification: Tree squirrels may disperse up to several tens of kilometers, but dispersal distance likely is usually not more than a few kilometers. Juvenile red squirrels generally settle on or adjacent to their natal territory (Haughland and Larsen 2004). Whitaker and Hamilton (1998) mentioned fox squirrels traveling 1.2 km daily between woodlots.

Unsuitable habitat includes areas lacking or largely devoid of trees.

Inferred Minimum Extent of Habitat Use (when actual extent is unknown): .1 km
Inferred Minimum Extent Justification: Based on a home range of 0.8 hectares (see Separation Justification).
Date: 08Mar2005
Author: Hammerson, G., and S. Cannings
Notes: Contains species in the genera SCIURUS and TAMIASCIURUS.
Population/Occurrence Viability
U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
Element Ecology & Life History Edition Date: 08Mar2005
Element Ecology & Life History Author(s): Hammerson, G.

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"Data provided by NatureServe in collaboration with Bruce Patterson, Wes Sechrest, Marcelo Tognelli, Gerardo Ceballos, The Nature Conservancy-Migratory Bird Program, Conservation International-CABS, World Wildlife Fund-US, and Environment Canada-WILDSPACE."

Citation for Amphibian Range Maps of the Western Hemisphere:
IUCN, Conservation International, and NatureServe. 2004. Global Amphibian Assessment. IUCN, Conservation International, and NatureServe, Washington, DC and Arlington, Virginia, USA.

Acknowledgement Statement for Amphibian Range Maps of the Western Hemisphere:
"Data developed as part of the Global Amphibian Assessment and provided by IUCN-World Conservation Union, Conservation International and NatureServe."

NOTE: Full metadata for the Bird Range Maps of North America is available at:

Full metadata for the Mammal Range Maps of North America is available at:

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