This species is found in the Rocky mountains west of Montana, In Idaho, eastern Washington state, southeast British Columbia and in the mountains of central and eastern Oregon.

Biogeographic Regions: nearctic (Native )

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: Central Rocky Mountains in North America, from southeastern British Columbia and southwestern Alberta, Canada, south through northern and eastern Washington, northeastern Oregon, northern and central Idaho and western Montana in the U.S. Elevational range mainly 700-8000 ft.

It is difficult to characterize these animals by weight, as fat storage for hibernation is a continual process throughout the summer months. The total length of a Columbian ground squirrel ranges from 325-410mm, of which 80-116mm is tail. These ground squirrels have stout bodies with short, dense fur. The nose and face are tawny. The dorsum is a cinamon-buff color with darker brown underfur. The eyes are ringed with a line of pale buff. The legs and venter are buffy, and the tail is black.

Range mass: 340 to 812 g.

Length: 41 cm

Weight: 812 grams

• Terrestrial

Columbian ground squirrels are found in alpine and sub-alpine meadows. Their distribution within their range is therefore very discontinous.

Terrestrial Biomes: savanna or grassland

Comments: Open habitat: high grass plateaus, sagebrush plains, valley grasslands, openings (meadows, clearcuts) in coniferous forests, alpine meadows, and stream banks. Not very tolerant of dry conditions. Typically burrows in friable or sandy soils in open ground or bank under boulder or log.

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

These vegetarians eat flowers, seeds, fruits and bulbs. Among preferred foods are dandelion, timothy, clover and yarrow.

Comments: Feeds on a wide variety of vegetation: roots, bulbs, stems, leaves, seeds, and berries. Also eats some animal food (e.g., insects, mice, dead fish). May climb into trees and shrubs to obtain buds and fruits.

Colonial. Population density of 32-35/ha was reported for central Idaho and Alberta; 25-62/ha on agricultural lands in Washington; density generally is uneven over large areas (see Elliot and Flinders 1991). See Festa-Bianchet and King (1991) for information on survivorship and reproduction during population increases and decreases in Alberta. In southwestern Alberta, intercolony dispersal was mainly by yearling males; usually dispersed less than 4 km but up to 8.5 km (Wiggett and Boag 1989). Average home range of adult male was about 0.4 ha, of adult female about 0.1 ha. Adult males defend (primarily during breeding season) core areas within home range. Adult females defend territory near nest burrow; exhibit strong site fidelity. Reservoir for Rocky Mountain spotted fever and bubonic plague. Prey for various carnivores and diurnal raptors. Populations can withstand heavy predation without declining (Murie, 1992, J. Mamm. 73:385-394).

Comments: Spends about 70% of year in hibernation. Active season is shorter at higher elevations (about 86 days in adults) than at lower elevations (about 100 days) (Can. J. Zool. 70:1364). May enter winter den and begin to hibernate during dry weather, July-October; emerges from hibernation February-April. Hibernation dates vary with elevation. Active from about 20 minutes after sunrise to about 10 min after sunset in spring-sum.

Breeding occurs during the early spring after these ground squirrels awake from their winter hibernation. The testes of the males develop during hibernation, and the squirrels are ready to mate shortly after they emerge from their burrows. The females emerge about one week after the males, and they ovulate shortly thereafter. As females approach estrus, their genitals become swollen and emit an odor most attractive to males of the species. Males locate females by this odor. Unmated females return to estrus in two weeks.

The average litter size is 2.7 young, but there is a great deal of variation. Litter size varies with both female size and elevation. Females living at lower elevations give birth to larger litters than conspecifics living at higher elevations. Similarly, larger females bear larger litters than smaller females.

The young are altricial when born. They weigh approximately 6.8-11.4 grams at birth, but they develop quickly. They have hair by 3 days of age, and they are able to walk and climb within 15 days. Juveniles nurse for about 30 days, but they remain near their mothers throughout the first winter of their lives.

Male columbian ground squirrels reach sexual maturity at about three years of age. Females may mate in their second season. Full adult size for both males and females is reached in the third year of life.

Mating occurs soon after females emerge from hibernation. Gestation lasts 24 days. Litter of 2-7 (average 2-4) altricial young is born May-late June. Nursing period usually lasts about 30 days. Sexually mature in 1-2 years; 22-33% survive to maturity (Zammuto and Millar 1985). In southwestern Alberta, reproductive success of females ranged from 0 to 19 yearlings produced over a lifetime (King et al. 1991).

Although not endangered, some conservationists are concerned about the effects of continued poisoning of these squirrels. Because of the negative impact these animals can have on ranching, many ranchers use poison to control poulations. Such actions may have negative effects on brown bear, coyote, marten, badger, mountain lion, and hawks that prey upon these animals.

IUCN Red List of Threatened Species: least concern

Canada

Rounded National Status Rank: N5 - Secure

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

Management Requirements: See Albert and Record (1982), Askham (1985), and Matschke et al. (1988) for information pertaining to the use of sodium floroacetate, zinc phosphide, gas cartridges, strychnine, and anticoagulants for ground squirrel control.

Because Columbian ground squirrels eat many of the same foods that free ranging cattle eat, ranchers are very concerned about the effects these rodents have upon their livestock. In addition, ground squirrels are hosts for spotted fever ticks and may function as natural reserviors for St. Louis encephalitis and Powassan viruses.

Comments: May damage crops (clover, oats, wheat, vegetables) or compete with livestock for food.

Comments: Various data indicate a close relationship between S. columbianus and S. parryii, but a mitochondrial DNA analysis indicated that S. parryii and S. richardsonii are more closely related to each other than either is to S. columbianus (MacNeil and Strobeck 1987).