Columbian Ground Squirrel

Spermophilus columbianus
Ground squirrel lg

As you peer across Chester field, just past the Maintenance/Fire Cache compound, you will notice movement along the edge of the road. You then notice the many little heads poking up in various places throughout the field, watching you as intently as you are watching them. Such is a normal sighting of the Columbian Ground Squirrel Spermophilus columbianus.

Physical Characteristics 

These small mammals have stout bodies with short, dense fur, sporting surprisingly beautiful colorations. Its head and back are brown, black, and grey with subtle white speckling throughout, its eyes ringed with a line of pale buff. The underside is a dark cinnamon hue and its slightly bushy tail is black. Columbian Ground Squirrels range in length from 11-15 inches, 3- 4 1/2 inches of that length being tail. It is hard to characterize these animals by weight due to significant seasonal variations, but can range anywhere from 12 to 28 ounces. Listen for the bird-like chirps and squeaks of the Columbian Ground Squirrel as they warn each other of potential dangers, search for mates, and defend their territories.

Habitat and Food Sources  

The Columbian Ground Squirrel can be found in western Montana, northern Idaho, eastern Oregon, eastern Washington as well as in certain areas of British Columbia and Alberta. Despite this moderate range, Columbian Ground Squirrels live in a wide variety of habitat types, from alpine and sub-alpine meadows to arid grasslands. They feed on flowers, seeds, fruits, bulbs, insects, eggs, carrion, and small vertebrates.

Lifestyle  

Columbian Ground Squirrels are social animals that live in large family colonies. Females typically remain with the colony that they are born into while males will emigrate from their natal ranges to find unrelated mates and new territories. Both males and females, however, are territorial. Males fight for their new designated home range, trying to keep other males from mating with the females, and the females defend their nest burrows. Both sexes use scent glands located near the mouth, on the side of the head, and on the back to mark their territories. The Columbian Ground Squirrel is generally active during the day and at night they retreat to their burrows.

Burrows can be expansive and elaborate, with specified sectors for hibernation, food storage, and travel. immediately after mating. The hottest months of July and August endanger them to overheating, so the burrow is the safest place to be. Females must wean their litters before being able to regain fat stores; time of birth thus makes the hibernation date variable. Aside from being an important prey base for other animals on the Refuge, ground squirrels contribute to the ecological system by loosening, mixing, and aerating soils, bringing nutrients from deep soil to the surface, increasing water infiltration into the soil, as well as increasing soil fertility and plant productivity.

 Hibernation 

The chamber designed for hibernation, the hibernaculum, holds a dome-shaped nest of shredded material that usually consists of grasses and other vegetation. Hibernaculum size varies based on the size of the individual. Young Columbian Ground Squirrels will often stay close to their mothers during the first winter, inhabiting a separate hibernaculum within the same burrow. For this reason, this species has an 87% overwinter juvenile survival rate. Drainage holes in the floor of the hibernaculum may prevent flooding and loss of life during the spring and fall seasons. Since they emerge from their hibernation well before the females do, male Columbian Ground Squirrels also have a food cache within the hibernaculum for consumption in the early spring, before green vegetation is readily available. The males enter hibernation earlier than the females, as they begin gaining weight  

Reproduction  

Columbian Ground Squirrels mate in the early spring immediately after waking from hibernation. When the females emerge a few weeks later and approach estrus, an odor is emitted that attracts males and initiates copulation. Once mated, the female with give birth to 3-5 young in May or June, though individuals in lower elevations will give birth to more young than those residing at higher elevations. After about three days the young will have hair and in two weeks they begin crawling and walking on their own. Young are weaned after about a month, but they remain close to their family group at least through the first winter.

Threats 

Columbian Ground Squirrels are not listed as endangered or threatened and are considered quite common. However, some conservationists are concerned about the future of these small mammals. Because Columbian Ground Squirrels eat the same types of food as free-ranging cattle and dig their burrows in pastures, ranchers have begun extensively using poison as population control. The use of poison may also negatively impact larger predators like black bears, coyotes, mountain lions, and hawks.

Facts About Columbian Ground Squirrel

Live in family groups

Diet consists of vegetation, insects, eggs and carrion

They hibernate 70% of the year

During hibernation their temperature drops and kidneys shut down