Today is Squirrel Appreciation Day, and this year I thought I would highlight two western species seen during my trip to Jasper National Park last July.
While I was hoping to see a Columbian Ground Squirrel in Alberta, I didn’t expect to find one living under the cabin we had rented along the Athabasca River! He was a handsome fellow, with a stout body and short, dense fur. His nose, face and chest were a tawny cinnamon colour, while his back appeared a gold-flecked gray. His eyes were dark with a pale ring around them.
A species of the central Rocky Mountains, this ground squirrel is found in open habitats such as sagebrush plains, valley grasslands, openings in coniferous forests, alpine meadows, and along stream banks. As its name suggests, it spends most of its time on the ground, though it sometimes does climb trees and shrubs to obtain buds and fruits. A strict vegetarian, its diet consists of flowers, seeds, fruits and bulbs, including dandelions, timothy, clover and yarrow.
The Columbian Ground Squirrel is diurnal and spends the night in a burrow beneath the ground. The burrow consists of a network of tunnels which may be as long as 20 metres in length and have an average of 11 entrances. These tunnels provide the squirrel safety during the active summer months and a place to hibernate in the winter.
Columbian Ground Squirrels are only active for approximately 30% of the year, and may spend seven to nine months hibernating. The burrow has a separate chamber (the hibernaculum) located up to 2 metres underground in which it spends the winter in a deep torpor. The squirrels often stockpile a small amount of seed in their hibernacula to provide food when they emerge from hibernation in early spring, as food sources may still be quite scarce. Hibernation can begin as early as mid-July or as late as mid-August. Males begin putting on weight for their winter sleep soon after mating and go into hibernation before females, often in July to avoid the heat of summer. However, females cannot gain the weight necessary for hibernation until after they have weaned their litters. The young remain close to their mothers throughout their first winter.
Climate change is having an adverse effect on this species. A 20-year study led by University of Alberta researchers has found that these squirrels are emerging from hibernation an average of 10 days later than normal as a result of cold, snowy weather lasting well into the late spring. While 10 extra days of sleep may sound like a good thing, it shortens the amount of time the squirrels have to mate, reproduce, and put on enough weight to survive the next winter. The plants that they feed on are only available for three or four months, and a late emergence from hibernation means that they have a shorter period of time to feed. The survival rate of the female ground squirrels in the study has dropped by 20%, and the population as a whole has gone from a period of growth 20 years ago to just maintaining its current stability.
The second western species that we found in Jasper was the Golden-mantled Ground Squirrel. While it looks quite similar to a chipmunk, this squirrel can be differentiated from chipmunks by the lack of any stripes on the face. This species is named for the golden-red mantle that extends from the head down over its shoulders. Males have a mantle that is brighter red in colour as well as a significantly larger brain.
Golden-mantled Ground Squirrels may live below or above the timberline, provided there is enough cover to shelter them. I saw my first one on top of Whistlers Mountain, when he approached a group of tourists so closely that he must have been accustomed to receiving handouts. He only had one ear. When no handouts were forthcoming, he turned away and found a bit of food to eat from within the rocks.
The Golden-mantled Ground Squirrel inhabits mountain slopes and foothills, alpine tundra, open areas in coniferous forests, rocky outcroppings and slides, margins of mountain meadows, and campgrounds. It lives in burrows beneath rocks, stumps, logs, bushes, or cabins, or in rock crevices. At low elevations, this species is active mainly between March and November, while the squirrels which live in the mountains or in areas with abundant snowfall are active between May and August. They do not sleep the winter away, but alternate between periods of torpor and wakefulness. While it is awake, this species does not spend its time eating, but instead moves about and rearranges the grasses, dried leaves and shredded bark that make up its nest. Occasionally it may leave its burrow and emerge to the surface.
Unlike the Columbian Ground Squirrel, the Golden-mantled Ground Squirrel is an omnivore. Its diet includes seeds, nuts, fungus, flowers, fruits, insects, voles, birds and their eggs, and carrion. This species is not of conservation concern as it is locally abundant and populations are distributed evenly over good habitat.
The Golden-mantled Ground Squirrel has been described as asocial, which is the least social out of five social group types. Interactions between individuals are mainly agonistic, with behaviours ranging from threat displays to the occasional fights between adults to sudden chases in which an individual tries to drive out the other Golden-mantled Ground Squirrels from the area. We saw one such chase between two squirrels on our visit to Mount Edith Cavell; it reminded me of the Red Squirrels in the woods back home or the Eastern Gray Squirrels in my backyard. Bonds between adults form only briefly during the breeding season, while the bonds between a mother and her young last until dispersal.
I found both species charming, although the Columbian Ground Squirrel was definitely the shyer of the two. And while the familiar American Red Squirrels and Eastern Gray Squirrels of Ontario can be seen running along tree branches, raiding bird feeders, or scolding intruders even now during the coldest days of winter, the ground squirrels of Jasper National Park are deep asleep in their hibernacula right now, waiting for spring’s return.