Photo: Ohio Department of Natural Resources
Ground squirrels play an important role in soil aeration. They help condition the soil for plant growth. Their body wastes contribute to the organic structure of the soil. Ground squirrels are also an important part of the food web, being preyed upon by several species of bird, mammal, and snake.
Two species of the four ground squirrels found in Illinois are described here. All ground squirrels are characterized by having a tail covered with fur, nesting in an underground burrow, and having internal cheek pouches. Most ground squirrels hibernate, and all four species are active during daylight hours. Ground squirrels avoid burrowing in areas subject to flooding.
Thirteen-lined ground squirrel (Spermophilus tridecemlineatus): The thirteen-lined ground squirrel is slender with large eyes and small ears. They have yellowish fur and 13 prominent alternating light and dark stripes on the back and sides. The light stripes are yellow to white, and the dark ones are black to reddish-brown with lighter spots. The thirteen-lined ground squirrel hibernates in winter. In the fall before hibernation, thirteen-lined ground squirrels weigh 8 to 9 ounces and are much larger than a chipmunk. However, by spring, when the squirrels come out of hibernation, they weigh only 4 to 5 ounces.
Franklin’s ground squirrel (Spermophilus franklinii): The Franklin’s ground squirrel is a little larger than the thirteen-lined ground squirrel, weighing 1 to 1½ pounds in the fall before hibernation. Franklin’s ground squirrels resemble eastern gray squirrels but have shorter, less bushy tails and smaller ears. They have brownish-gray fur speckled with black and the underparts vary from yellowish-white to gray or buff. The Franklin’s ground squirrel is listed as a State Threatened species in Illinois.
Thirteen-lined and Franklin’s ground squirrels occur in the northern two-thirds of Illinois. The southern limit of these ground squirrels in Illinois seems to correspond with the Shelbyville glacial moraine. Thirteen-lined ground squirrels are abundant in many areas of Illinois, but Franklin’s ground squirrels are uncommon and are listed as a threatened species.
Ground squirrels are diurnal, meaning that they are active during the day. All ground squirrels are solitary; however, since they are not very territorial, many may be seen in close proximity, particularly if there is a good supply of food at that location.
Ground squirrels play an important role in soil aeration, and they help condition the soil for plant growth. Their body wastes contribute to the organic structure of the soil. Ground squirrels are also an important part of the food web, being preyed upon by several species of bird, mammal, and snake.
Ground squirrels are not considered to be a public health concern in Illinois.
Franklin’s and thirteen-lined ground squirrels are both found in grasslands or prairies. Thirteen-lined ground squirrels live in short grasslands or in weedy areas with short vegetation. They are often found in golf courses, cemeteries, parks, and roadsides. Franklin’s ground squirrels are found in slightly taller grass, but they prefer the grass to be short enough to allow them to stand on their hind legs and see over the grass.
Thirteen-lined ground squirrels feed extensively on grasses, weeds, seeds, cultivated plants, and insects. Franklin’s ground squirrels are omnivorous. They will eat carrion, insects, bird eggs, and small birds as well as plant material.
Thirteen-lined and Franklin’s ground squirrels have only one litter per year, usually in late May. Gestation is 27 to 28 days, with six to seven young per litter. The young are weaned in about four weeks.
If ground squirrels are causing problems there are several control strategies available. Note: Franklin’s ground squirrels are threatened in Illinois and are protected. If you are having a problem with Franklin’s ground squirrels, CONTACT your local Illinois Department of Natural Resources district wildlife biologist for assistance.
Exclude ground squirrels from small areas by installing 18-inch high ¼- to ½-inch mesh hardware cloth (also called hail screen) buried six inches below ground.
To keep ground squirrels from burrowing under foundations, place hardware cloth bent at a 90-degree angle along the foundation and cover with soil.
There are currently no repellents registered for use against ground squirrels in Illinois.
If other control methods have failed, thirteen-lined ground squirrels can be trapped and removed. A permit is not needed. Live traps baited with seed can be used to capture the animals. If you plan to release the squirrel, it is recommended that you release the squirrel five to 10 miles away. You will need written permission of the landowner before you release the squirrel. Rat-sized snap traps are efficient if ground squirrels are to be lethally removed. Nuisance wildlife control operators will trap and remove thirteen-lined ground squirrels for a fee. Franklin’s ground squirrels may not be removed without a special permit.
In Illinois, thirteen-lined ground squirrels are not protected by the Wildlife Code. They may be removed without a permit.
The Franklin’s ground squirrel is listed as a threatened species in Illinois. Handling, capture, relocation, or lethal removal of any threatened species in Illinois is illegal and strictly prohibited without the issuance of a formal endangered and threatened species permit issued by the Illinois Department of Natural Resources (IDNR). For information about endangered and threatened species, contact Joseph Kath, IDNR Endangered Species Program Manager, at: Joe.Kath@illinois.gov
Photo: Adele Hodde, IDNR
Photo: Alberto Cea, CC BY-SA 3.0
Photo: Gordon Garcia
The Wildlife Illinois website was authorized by the Illinois Department of Natural Resources (IDNR) in partial fulfillment of project W-147-T. The website was developed by the National Great Rivers Research and Education Center, 2wav, and the IDNR in partnership with the United States Department of Agriculture Animal and Plant Health Inspection Service Wildlife Services and University of Illinois Extension to provide research-based information about how to coexist with Illinois wildlife.
