Friday, September 17, 2010

A Few More Squirrels

The Columbian Ground Squirrel can be found in eastern British Columbia, western Alberta, eastern Oregon, Washington, northern Idaho, and western Montana. They like open alpine meadows, dry grasslands and brushy areas. The majority of the Columbian ground squirrel's diet is made up of grasses and plant parts like stems, leaves, bulbs, fruits and seeds. Occasionally it will eat birds, insects and other small animals. Columbian ground squirrels live in colonies. Females usually stay with the colony they were born into, males will leave their birth colony. The Columbian ground squirrel hibernates seven or eight months out of the year. It may begin hibernating as early as July. It has a special hibernation chamber in its burrow that is sealed off from the rest of the burrow with a plug of dirt. It puts on fat in the summer and stores seeds and bulbs in its hibernation chamber to eat when it wakes up in the spring:
Columbian Ground Squirrel
photo taken in eastern British Columbia

John Muir described the Chickeree (or Douglas) Squirrel as "by far the most interesting and influential of the (squirrels.)" It is a small, lively, bushy-tailed tree squirrel, enchanting to watch. Their appearance varies according to the season. In the summer, they are a grayish or almost greenish brown on their backs, and pale orange on the chest and belly, while legs and feet appear brown. In the winter, the coat is browner and the underside is grayer; also, the ears appear even tuftier than they do in summer. Like many squirrels, Douglas Squirrels have a white eye ring. ouglas Squirrels live in coniferous forests, from the Sierra Nevada mountains to coastal British Columbia. They prefer old-growth or mature second-growth forest, and some authors regard them as dependent on its presence. They are active by day, throughout the year, often chattering noisily at intruders. In summer nights, they sleep in ball-shaped nests that they make in the trees, but in the winter they use holes in trees as nests. They are territorial; in winter, each squirrel occupies a territory of about 10 000 square metres, but during the breeding season a mated pair will defend a single territory together. Groups of squirrels seen together during the summer are likely to be juveniles from a single litter:
Chickeree Squirrel
photo taken in Western Oregon

Rock squirrels are one of the largest squirrels, growing to nearly a foot in length, not including their long, bushy tails which are nearly as long as their bodies. When alarmed they whistle a short, sharp oscillating call. They are found in the Sonoran Desert, and from Southern Nevada, Utah, Colorado, Oklahoma, and south through Arizona, New Mexico and into Mexico. Rock squirrels live in arid canyons, rocky cliff areas, and boulder piles, but have also been known to burrow in urban or suburban areas.  They avoid open flats and montain forest areas. Burrows dug with their sharp claws and muscular legs shelter them, providing safety, living space and food storage. Burrow systems can be complex and lengthy, enlarged over years. Entrances are usually hidden beneath rocks and can be greater than 3 inches in width. Rock squirrels in the northern reach of their habitat hibernate in their burrows during the colder months of the year. In southern areas, rock squirrels may not hibernate at all. They are active in the early morning and late afternoons when it is warm - when very hot, they may estivate. They are social, and live in colonies with several females and one dominant male that will fight other mature males to protect the group. There may be subordinate males at the outer boundaries of the group. Rock squirrels can climb nearly as well as tree squirrels. They have been seen at the tops of agaves, junipers and mesquites, feeding on flowers, buds and beans.

Rock Squirrel
photo taken in White Mountains, Arizona

The Western Gray Squirrel is found along the Pacific Coast of Canada and the United States. Compared to the Eastern Gray Squirrel these squirrels are shy, and will generally run up a tree and give a hoarse barking call when disturbed. They are forest dwellers, and can be found at elevations up to at 2,000 m or more. Time on the ground is spent foraging, but they prefer to travel distances from tree to tree. They are strictly diurnal and feed mainly on seeds and nuts, particularly pine seeds and acorns, though they will also take berries, fungus and insects. Pine nuts and acorns are considered critical foods because they are very high in oil and moderately high in carbohydrates, which help increase the development of body fat. They feed mostly in trees and on the ground. They generally forage in the morning and late afternoon for acorns, pine nuts, new tree buds, and fruits. When on alert, they will spread their tails lavishly, creating an umbrella effect that shields them and possibly provides cover from overhead predators:

Western Gray Squirrel
photo taken at Mercer Slough, Washington

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