Chipmunks and Ground Squirrels

Image © Chadwick Cipiti creativecommons.org/licenses/by/2.5/

Chipmunks and ground squirrels are commonly mistaken for the same animal, but they both have distinguishing marks and different habits.

The chipmunk has five dark brown stripes, which run from its head to its rump. It scurries about with its tail straight up, looking like a zooming remote-control car. It eats a variety of berries, nuts and seeds and may occasionally climb trees to find food. It may also eat small animals, including insects, earthworms, slugs, young mice and birds, and small frogs or snakes. Some chipmunks may hibernate while others continue to be active throughout the winter.

The 13-lined ground squirrel has 13 lines on its back, some spotted, which run from its head to its rump. It prefers open grasslands where it feeds on equal amounts of plants and animals. Its diet includes insects, grasshoppers, moths and butterflies, earthworms, young birds and mice, seeds, fruits, nuts, roots, and foliage. At the end of summer, the 13-lined ground squirrel will fatten up for hibernation.

Living in Your Yard

Chipmunks prefer timber borderlands but have adapted to suburban neighborhoods, where they will dig tunnels under shrubs and trees, flowerbeds, rocks and woodpiles, stone walls, sidewalks, and porches. 

Neatly manicured lawns, golf courses and cemeteries are excellent habitats for 13-lined ground squirrels, which prefer open grasslands. The holes to the tunnels are about 2 inches wide.

Chipmunks and 13-lined ground squirrels have multiple entrances to their burrows. (Chipmunks normally have one active entrance.) These tunnels can be 20 to 30 feet long, making it difficult to evict the animals. 

Preventing Problems

  • Do not encourage chipmunks or ground squirrels by feeding them.
  • Do not allow spills to accumulate below bird feeders.
  • Install and maintain chimney caps before animals move into your chimney.
  • Use welded wire to prevent animals from accessing openings under decks, elevated sheds, concrete slabs and porches. Secure outside access to crawl spaces.

Recommended Deterrents

  • Chipmunks and ground squirrels are easily frightened. Leave inflated beach balls in the yard. The wind will blow them around and frighten the animals. Scarecrows, plastic bags on sticks or other objects that move in the wind are also effective; but as the animals grow used to these items, their effectiveness will diminish.
  • Place lighting, such as bright flashlights, flood lamps or blinking strands of holiday lights, in the den. It is best to leave the lights on 24 hours a day. If this is not possible, the lights must be on at night to disturb the animal’s sleep.
  • Play a radio, portable alarm clock, noisy children’s toy or anything that makes noise repeatedly either in or near the den. It is best to have the sound on for 24 hours a day. If this is not possible, the sound must be on at night to disturb the animal’s sleep.
  • Place ammonia-soaked rags in the den for one week. (Ammonia has an irritating smell.) Over time, the ammonia will dissipate, so it is important to resoak the rags daily. Do not use ammonia-soaked rags March through August; they may injure infant wildlife too young to escape.
  • If the animal has established a den site in a chimney, usually on the smoke shelf in the fireplace flue, use the same techniques listed above. Lower a light down into the chimney, place a bowl of ammonia on the fireplace grate, and place a radio inside the fireplace. Do not try to “smoke out” the animals. They can be overcome with smoke, and then you will be faced with physically removing them yourself.

For deterrents to be successful, it is important to use all of the techniques at the same time. To determine if an animal has left a den site, wad up newspaper, and pack it into the den entrance. (This also helps to hold in ammonia fumes.) If the animal is still using the den, the newspaper will be pulled out. If after a few days the newspaper has not been disturbed, securely repair any openings. Failure to do so may result in another animal moving in.

Gardens

The best way to keep chipmunks and ground squirrels out of your garden is to use chicken wire as a barrier. When planting bulbs, pick up any skins that flake off, and spread a thick layer of mulch over the bulbs. Then, place the wire on the flower bed, and scatter a light layer of mulch or leaves on top. Remove the wire in spring so the bulbs can grow.

Daffodils, squills, grape hyacinths and crown imperial bulbs are distasteful to chipmunks and ground squirrels. The crown imperial has a horrible smell, and below-ground diners are known to avoid it. Plant crown imperials among tulips and other “tasty” bulbs.

Other taste deterrents work, such as spraying a mixture of 1 gallon of water and 2 tablespoons of hot sauce or garlic puree onto the plant, but they need to be reapplied after a heavy dew or rain. Nurseries or home centers may carry commercial products as well.

Public Health Concerns

Chipmunks and ground squirrels are not considered significant sources of diseases that can be transmitted to humans. They may carry rabies, but there have not been any reports in DuPage County in recent years.

What Not To Do

  • Trapping and removing an animal is not always a solution to the problem. Removing the animal is illegal without the proper permits and only creates an open space for another animal. A trapped adult may also leave young behind to die of starvation in an inaccessible area. Focus on removing the attraction, not the animal.
  • Never move young from a den. 
  • Do not use poisons. They are inhumane and may be illegal. They can also result in secondary poisoning of raptors, wild scavengers and neighborhood pets.
  • It is illegal to keep wild animals, even for a very short time. They have specialized nutritional, housing and handling needs that you are unlikely to be able to provide. Inexperienced individuals who attempt to raise or treat them inevitably produce unhealthy, tame animals that cannot survive in their natural habitats.

Willowbrook Wildlife Center

If you come across a wild animal and are concerned, leave it alone. Call Willowbrook Wildlife Center for advice at (630) 942-6200. The center is located at 525 S. Park Blvd. in Glen Ellyn and is open 9 a.m. to 5 p.m. every day except select holidays. Recorded messages provide general information for callers when the center is closed.

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