If you have mature trees in your yard or neighborhood, you’ve probably seen tree squirrels scurrying up and down and leaping from branch to branch.

Illinois is home to four kinds of tree squirrels: eastern gray squirrels, fox squirrels, red squirrels and southern flying squirrels. Fox squirrels and gray squirrels are common across the state. Southern flying squirrels also live across Illinois, but they are not as numerous and are more common in the southern part of the state, according to Wildlife Illinois. Red squirrels are found only in the northeastern part of the state, including Will County.

Squirrels are active year-round, but you may not see them as much in winter, when they will stay in their nests for longer periods during extreme cold or severe weather. They typically nest in tree cavities, but will build nests of leaves when they cannot find a cavity, Wildlife Illinois reports.

Fox squirrels, gray squirrels and red squirrels are active during the day, but southern flying squirrels are nocturnal. All four kinds of tree squirrels spend time on the ground and in trees, but fox squirrels and red squirrels tend to spend more time on the ground.

Ecological effects

Tree squirrels mainly eat nuts and seeds, and as such they help spread seeds and contribute to reforestation because they don’t always return for all the seeds they bury, Wildlife Illinois reports. They also play a role is dispersing fungal spores throughout forested areas, helping propagate those species as well. 

Squirrels play an important role in the food chain because they are a food source for many predators, according to Wildlife Illinois. Among the animals in Illinois that hunt squirrels are foxes, coyotes, hawks and owls.

Mating and reproduction

Tree squirrels typically have two litters of babies a year, although younger squirrels will often have only one litter. Baby fox squirrels are typically born in April or May and then again in August or September. Gray squirrels are usually born between February and April and again in August or September, according to the University of Illinois Wildlife Medical Clinic. Litters vary in size from two to five offspring.

Southern flying squirrels typically give birth in February or March and again between May and July, according to Animal Diversity Web. Red squirrels are the species most likely to have just one litter per year, but two litters are most common in the parts of their range with a warmer climate, Animal Diversity Web reports. Red squirrels typically mate between March and May. Those that have a second litter will mate again in August or early September.

Depending on the species, squirrels are weaned when they are between 6 weeks and 8 weeks old, the wildlife clinic reports. They will stay in the nests with their mothers for a few more weeks, but they are fully independent and living on their own between 10 weeks and 12 weeks old.

Health risks

In Illinois, tree squirrels do not pose health risks to the public, Wildlife Illinois reports. Squirrels can carry parasites, but none have serious effects on human health.

If you’ve seen squirrels with patches of fur missing, this can be a sign of mange or a fungal disease, according to Wildlife Illinois. This is not normally cause for concern because otherwise healthy squirrels can recover from these conditions.

Problems and solutions

Tree squirrels’ excellent climbing and jumping abilities serve them well in the wild, but it also sometimes allows them to cause problems around our homes. In particular, they can be a nuisance on bird feeders because they can make quick work of most feeders not specifically designed to keep them at bay. To keep them out of the bird seed, consider adding a baffle to a bird feeder or look for a feeder that is designed to prevent squirrels from getting to the food, the Cornell Lab of Ornithology advises. You can also put your feeder in a place that’s hard for them to reach, or put out food specifically for the squirrels, like cracked corn, so they’re less likely to eat the bird food. One note: Do not grease the poles your bird feeders are on. This can be harmful to birds because the grease can mat down their feathers, making it more difficult to fly and also affecting their ability to stay warm.

 

Squirrels will sometimes chew through siding or other materials to gain access to an attic or enlarge an opening, Wildlife Illinois reports. If they get inside a building, they can cause further damage by chewing through electrical wiring or insulation. 

You can help keep squirrels from accessing your home or other buildings by cutting back tree branches at least 10 feet from buildings, eliminating their ability to jump to it. It’s also important to regularly check your home to make sure it is free from holes or damage that squirrels may use to access your attic and to repair any holes immediately.

On occasion, squirrels may fall down uncapped chimneys. When this happens, they are not able to climb back up to escape, the wildlife clinic reports. You can help them by dropping a rope down the chimney that they can climb. If a squirrel gets into your house, shut off access to the room they are in and open a window so they will be able to escape. Prevent further problems by installing a cap on the chimney.

If animals on your property continue to cause damage after corrective measures have been taken, consider humanely removing and relocating them only as a last resort. Trapping a squirrel to remove it from your property requires a permit from IDNR. If you do not want to remove it yourself, contact a licensed wildlife control operator to contract their services.

All wildlife in Illinois are under the jurisdiction of the Illinois Department of Natural Resources. The Forest Preserve District of Will County does not treat, rescue or remove wildlife from public or private property. Both the Illinois Department of Natural Resources and Wildlife Illinois maintain lists of wildlife rehabilitators you can contact for assistance with injured wildlife. 

 

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