Tuesday, September 17, 2013

Native Species Profile - Eastern Chipmunk

Mid-Michigan is home to eight species of squirrels. 

Three species of tree squirrels call the area home.  The smallest of the tree squirrels is the Red or Pine Squirrel (Tamiasciurus hudsonicus).  Next largest is the Gray Squirrel (Sciurus carolinensis) which comes in several color variants, including black.  The largest of the tree squirrels is the Fox Squirrel (Sciurus niger).

The ranges of the Southern Flying Squirrel (Glaucomys volans) and Northern Flying Squirrel (Glaucomys sabrinus) overlap in Mid-Michigan.  These species do not truly fly, but rather can glide from a higher position to a lower one using flaps of skin that stretch between their front and hind legs.  The flying squirrels are nocturnal and are rarely seen.

Finally there are three species of ground squirrels can be found in the region.  The Thirteeen-line Ground Squirrel (Spermophilus tridecaemlineatus), Woodchuck (Marmota monax), and the Eastern Chipmunk (Tamias striatus).  Of these three, the Thirteen-lined Ground Squirrels is strictly a ground-dweller, while both the Woodchuck and Eastern Chipmunk both can and do climb trees.

The Eastern Chipmunk is the smallest of these three species with a body length measuring six to eight inches and a tail of three to four inches.  It weighs between 2.8 and 5.3 ounces. 

The Eastern Chipmunk is an overall reddish-brown color on its upper parts.  Its upper back is lined with five dark brown stripes alternating with light brown stripes that run from the shoulders to the lower back where they fade out.  The tail typically is covered with the same reddish-brown fur as the body with longer black-tipped guard hairs giving it grayish appearance.

The Eastern Chipmunk is a rodent and like most rodents it eats an omnivorous diet.  Common food items include seeds, fruit, nuts, leaf and flower buds, insects, bird eggs and mushrooms.  It will also consume baby birds, mice, frogs and small snakes on occasion.  It also stores large quantities of food in its underground burrow.  It transports food to its burrow in expandable cheek pouches.  This omnivorous diet and the tendency to store foods allows the Chipmunk to make use of a number of habitats.  The Eastern Chipmunk is commonly found in hardwood and coniferous forests, along forest edges, and in suburban areas.

The burrows of Eastern Chipmunks can be quite extensive and often feature several hidden entrances, long tunnels, and chambers for sleeping, food storage, and waste disposal.  The Chipmunk retreats to these burrows when threatened by predators, of which it has many.  The Eastern Chipmunk also enters this burrow to survive the winter months, relying on food stored in its larder.  While not a true hibernator like the Thirteen-Lined Ground Squirrel and Woodchuck, the Eastern Chipmunk will enter periods of torpor throughout the winter - reducing its activity levels and bodily functions to conserve energy.  It will occasionally venture out of its burrow on warm winter days or if its food supplies begin to run low.

Basic Information

Eastern Chipmunk 
Tamias striatus

Size:  6-8” long w/ 3-4” tail

Weight:  2.8-5.3 ounces

Habitat:  forests, forest edges, suburban areas

Eats:  seeds, fruit, nuts, insects, fungi, buds, flowers, frogs, baby birds, bird eggs, small snakes

Is Eaten By:  raven, great blue heron, hawks, owls, weasels, raccoon, red fox, gray fox, bobcat, lynx, coyote, house cat, dog

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