Tree Squirrels

Image © Mario Castellanos

Fox and gray squirrels live in DuPage and have adapted to suburban neighborhoods. Gray squirrels are gray on the head and back and white- or buff-colored beneath. Fox squirrels are reddish and are larger than gray squirrels. The gray squirrel has a smaller home range and is more social; the fox squirrel’s range is larger and more solitary.

Living in Your Yard

Squirrels use two basic types of natural dens, tree cavities and leaf nests, but they will also build nests in attics, garages and eaves. They use two or more nests concurrently throughout the year. Females have two litters a year. The first is born between February and April, the second between August and September. If possible, consider “living with them” until the young leave the nest at 10 to 12 weeks. 

Squirrels are active during the day, foraging for food in the early morning and late afternoon. They do not hibernate in winter but will become less active during inclement weather. 

A Squirrel in the House

A squirrel that has entered a house has done so by accident. If you know its location, open a window or exterior door in that room, and close interior doors to limit access inside the house. Left alone, it will find the opening and leave.

While a squirrel can jump from a second story window onto a grassy area without harm, a first-floor exit is preferable; a squirrel should never be forced to jump from that height. If the squirrel cannot leave on its own, set a live trap. Place a trail of bait leading from one foot outside into the trap, and leave it alone for a few hours. Once the squirrel is trapped, release it outside onto your property. Releasing it on your own property is your only legal option unless you have obtained permits from the Illinois Department of Natural Resources.

Preventing Problems

  • Do not encourage squirrels by feeding them.
  • Keep pet food and water dishes inside, especially at night.
  • Don’t let spills accumulate outside bird feeders.
  • Keep grills and barbecues clean. Even small food scraps may attract squirrels.
  • Trim tree limbs that provide access to your roof.
  • Repair broken, weak or rotted areas on your roof, soffit and fascia. 
  • Install and maintain chimney caps before animals move into your chimney.
  • Use welded wire on the inside of attic vents to deny access to the attic.

Recommended Deterrents

  • Wrap a 4- to 6-foot-wide piece of aluminum flashing around tree trunks so that squirrels cannot get a foothold on the bark. Make sure the aluminum flashing is a minimum of 4 feet from the ground. This will deny squirrels access to the tree and your roof. This provides an immediate solution, but you should leave the flashing up for five to seven days.
  • Grease downspouts with a mixture of petroleum jelly and crushed red pepper. Squirrels will be unable to climb the downspout due to the slippery surface. This provides an immediate solution, but you should keep the downspouts greased for five to seven days.
  • Squirrels are agile enough to walk on power and telephone lines. The two techniques listed above may deny them access to the pole. See how they are getting to the wires to determine if these techniques will work.
  • 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 in the spring or late summer; 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.


The best way to keep tree 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.

Bird Feeders

Grease the feeder pole with petroleum jelly or axle grease. Mix crushed red pepper into birdseed to keep squirrels from eating. The pepper will not affect the birds because they have a poorly developed sense of taste. Bird-supply stores may also carry deterrents.

Gnawing on Wood

To deter gnawing, mix petroleum jelly and crushed red pepper, and spread the mixture on the affected area. Ammonia-soaked rags can also be effective.

Public Health Concerns

Squirrels may carry rabies, but there have been no reports in DuPage County in recent years. Sarcoptic mange is a common among squirrels. The most obvious sign is a hairless squirrel or one with patches of missing hair. Mange can be passed between wild and domestic animals, although direct long-term contact is necessary. Mange is treatable with two to three injections of a parasiticide. Squirrels that eat a poor diet, such as one high in fat, like peanuts, are more prone to mange.

Squirrels can inflict nasty bites and, as with all wild animals, should never be hand-fed or encouraged to approach humans. If your pet gets into a fight with a squirrel, check it for wounds, and call your veterinarian for advice.

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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