Getting Squirrels Out of Chicagoland Attics and Keeping Them Out

Gray, fox, red and flying squirrels: which one is upstairs

Four tree squirrels turn up in Chicagoland houses, and knowing which one you have changes the plan. The eastern gray squirrel is the most common in Chicago itself and the older inner suburbs: silver-gray with a white belly, about a pound, quick and agile. Black squirrels seen in some neighborhoods and suburbs are usually a dark color phase of the same species. The fox squirrel is larger, often a pound and a half or more, with a rusty orange belly and tail, and it is especially common in suburban yards, parks and open woodland edges.

In McHenry County, Lake County and southeast Wisconsin, and anywhere with spruce and pine plantings, the small, noisy American red squirrel also enters homes. The one people rarely see is the southern flying squirrel, a soft, gray-brown animal with huge dark eyes and a gliding membrane between its legs. Flying squirrels are nocturnal, live in groups, and can squeeze through openings smaller than an inch. When homeowners hear activity in the attic all night rather than at dawn and dusk, flying squirrels are a strong suspect. Chipmunks and thirteen-lined ground squirrels cause digging damage around foundations and patios but rarely get into attics.

Morning scratching, chewed trim and other signs

Gray and fox squirrels are active by day, so the classic complaint is running, scratching and rolling sounds in the ceiling shortly after sunrise and again in late afternoon, often with a pause in the middle of the day. Some homeowners hear what sounds like nuts being rolled across the attic floor. Squirrels cache acorns, walnuts and seeds, and they also drag in leaves, insulation and shredded paper to build nests.

Outside, look for a chewed hole with rough edges, often about the size of a fist, at a roof corner, along the soffit, at the end of a ridge vent, at the gap behind a gutter, or in the wooden frame around a gable louver. Fresh chewing shows bright wood. Squirrel tracks on dusty attic joists, droppings shaped like small rounded pellets, and urine stains on ceilings are other clues. Flickering lights or a breaker that trips for no obvious reason can point to chewed wiring, which needs an electrician's attention as well as squirrel control.

• Scampering at dawn and dusk points to gray or fox squirrels
• Activity through the night points to flying squirrels
• Fist-sized holes at roof corners, soffits and ridge vents
• Leaf nests or acorn caches in the attic
• Chewed wires, ductwork or plastic vent covers

Why so many Chicago-area roofs get chewed

The region's urban forest is the main reason. Chicago's older neighborhoods are lined with parkway trees planted decades ago, and many suburbs, from Oak Park and Evanston to Glen Ellyn and Hinsdale, have mature oaks, maples, walnuts and hickories whose limbs reach over rooflines. Squirrels use those branches, along with utility lines and fences, to reach the roof without ever touching the ground. Oaks and walnuts also produce heavy nut crops in some years, which can boost squirrel numbers the following spring.

Building details invite entry. Chicago bungalows and frame houses often have wooden soffits and fascia that have softened with age, along with gable vents and attic louvers that were never screened. Many newer homes have continuous ridge vents and aluminum soffit panels that squirrels can pry apart. Roof-to-wall joints where a dormer or a lower roof meets a higher wall leave a small gap behind the flashing that squirrels quickly enlarge. In two-flats and attached townhomes, a single opening can lead to a shared attic or cornice that serves several units.

In the city, alleys add another highway. Overhead utility and cable lines run along most Chicago alleys and connect to the rear of nearly every house and garage, and squirrels run them like tightropes. Detached garages with old wood fascia and roll-up doors that never quite close become secondary nests, and from the garage roof it is a short jump to a back porch roof or a rear dormer. Suburban lots with fewer alleys still have fences, decks and play sets that serve the same purpose.

Wiring, insulation and the fire risk nobody sees

A squirrel's incisors grow continuously, and it gnaws constantly to keep them worn down. In an attic that means wiring insulation, plastic plumbing vents, flexible ductwork, roof sheathing and the wooden frames of vents. Fire officials and insurers have long linked chewed wiring by rodents, including squirrels, to some house fires. Old knob-and-tube wiring and early cloth-insulated cable still found in some pre-war Chicago homes is especially vulnerable once its covering is damaged.

Nesting squirrels also compress and soil insulation, which lowers its effectiveness, and their urine and droppings can stain drywall and plaster. When a squirrel dies inside a wall or ceiling, the odor can linger for weeks. Squirrels are not considered a significant rabies risk, but they carry fleas and mites that can move into living spaces once the squirrels are gone, so a post-removal treatment of the attic is sometimes recommended. Water damage is the other hidden cost. A hole chewed through a soffit or roof edge lets in rain and melting snow, and ice dams in a Chicago winter can force water through an opening that looked small in fall.

Two litters a year shape when to act

Gray and fox squirrels in northern Illinois usually breed twice a year. The first mating season runs in mid to late winter, with litters born in late winter and early spring, often March and April. A second round of mating in late spring and early summer produces litters in late summer, typically around August. Gestation is roughly six weeks, and the young stay in the nest for about two months before they venture out. Attic litters are common because a warm, dry attic is a much better nursery than a leaf nest in a tree.

This matters because sealing a hole while young are inside leads to frantic chewing by the mother trying to get back in, or dead young decaying in the attic. A specialist will check for a nest before installing any exclusion device. If babies are present, the safest approach is often to wait until they are mobile, or to remove them carefully by hand and give the mother a chance to move them. Fall brings another rush of calls, when squirrels look for winter dens and young from the summer litter seek their own territory, and that is when homeowners notice new chewing on soffits and vents.

Weather shifts the calendar a little each year. A mild January can bring early mating and nests by late February, while a cold, late spring can push the first litters into May. Heavy acorn years in the oak-rich suburbs and forest preserve edges tend to mean more surviving young the next season, so a roof that had no trouble last year may still be tested this year. Paying attention to the first sounds of the season is the best early warning.

How a licensed specialist removes squirrels

Effective squirrel removal is mostly about finding every opening, then letting the animals leave and making sure they cannot get back in. A thorough provider will inspect the entire roof, not only the obvious hole.

Squirrels also end up in places other than the attic. A squirrel that falls down an uncapped chimney can get stuck on the smoke shelf or damper and may need to be lifted out with a pole and net or let out through the fireplace into a closed room with an open exterior door. Squirrels in wall voids, usually from a hole at the roof edge, often need a small access opening to confirm the void is clear. After the animals are out, many providers vacuum or remove nesting debris, clear food caches that attract insects, and treat for fleas and mites if needed.

• Inspect the roof, soffits, vents, chimney, gutters and attic to find active entries and possible future ones.
• Check the attic for nests and young before deciding on a method.
• Install a one-way exclusion funnel or door over the main entry so squirrels can exit but not return.
• Seal secondary openings with galvanized or stainless steel mesh and metal flashing.
• Use live traps only where exclusion is not practical, following state rules.
• Return to remove the exclusion device and make the final repair once activity has stopped.
• Recommend tree trimming, chimney caps and replacement of chewed vents or soffit sections.

Permits and state rules

Gray and fox squirrels are game species in Illinois, with a regulated hunting season, and nuisance removal for a fee is overseen by the Illinois Department of Natural Resources through its nuisance wildlife control permit program. A provider you hire to trap or remove squirrels should hold the appropriate permit and follow the rules on how captured animals are handled. Releasing squirrels in a park or forest preserve is generally not allowed, and relocated squirrels have poor survival rates. In northwest Indiana the Indiana Department of Natural Resources sets the rules, and Wisconsin has its own nuisance wildlife regulations for Kenosha County.

Safety matters too. Squirrels can bite hard when cornered or handled, so never reach into a nest or try to catch one that has entered a room. Open a window or exterior door, close interior doors, and give it a clear path outside. If a squirrel gets inside a living space through a fireplace or attic hatch, it usually means the attic entry is already well established.

Ground-dwelling relatives need care too. Eastern chipmunks and thirteen-lined ground squirrels fall under Illinois wildlife rules as well, and burrows under patios, stoops and foundation walls are usually handled with exclusion, burrow repair and habitat changes rather than poison baits, which can harm pets, birds of prey and other non-target animals.

DIY approaches that usually fail

The most common mistake is sealing the hole while squirrels are still inside. A trapped squirrel will chew a new exit, often through drywall or a ceiling, and if young are left behind, the result is a strong odor problem within days. Another frequent error is patching holes with wood, plastic mesh or spray foam, which squirrels can chew through in minutes. Only metal mesh or flashing holds up over time.

Repellents such as predator urine, mothballs and ultrasonic devices are widely sold, but none reliably drives squirrels out of an established attic nest, and mothballs used outside their labeled purpose are a pesticide misuse. Cage trapping on your own can also go wrong. In spring, trapping a nursing female orphans her litter, and catching and relocating squirrels yourself may violate state rules. Climbing onto a steep roof or ladder to patch an eave is a serious fall risk, particularly on two-story homes and older roofs with brittle shingles.

Prevention for tree-lined blocks

Once squirrels are out, these steps reduce the chance that the next generation finds a way back in.

Prevention matters most in the months before the two breeding seasons. A careful inspection in late fall, after leaves drop and rooflines are easy to see, and again in early summer catches fresh chewing before it becomes a full entry.

• Trim branches so they end at least six to eight feet from the roof.
• Cap chimneys and replace plastic roof vents with metal-guarded vents.
• Screen gable vents and attic louvers with heavy-gauge metal mesh.
• Check ridge vent ends, roof corners and dormer joints every fall.
• Fix rotted soffit and fascia boards promptly.
• Move bird feeders away from the house and use baffles on feeder poles.
• Pick up fallen walnuts and acorns near the foundation.
• Keep garage doors closed so squirrels do not nest in rafters or vehicles.

Cost factors for squirrel work

The price of squirrel removal depends on what the inspection finds. Key factors include the number of active and potential entry points, roof height and pitch, the type of roof and vents, whether young are present, the need for follow-up visits, and how much repair or cleanup the attic needs. Replacing chewed wiring is electrical work and is typically quoted separately. A detailed estimate that lists each opening to be sealed and the materials to be used makes it easier to compare providers and understand what is covered.

Homes with complicated rooflines, such as the period-revival houses with multiple gables and dormers common on the North and Northwest sides and in older suburbs, usually take longer to seal than a simple ranch or bungalow roof. Seasonal timing can also affect the schedule, because waiting for young to mature may mean a second visit. Ask whether the price includes sealing all vulnerable points or only the active entry, since squirrels often return to a second weak spot within weeks if only the first is fixed.