How to tell which animal you have before you spend a dollar
Three questions get you most of the way. When does it happen, how heavy does it sound, and is the noise above you or below you. After dark and heavy, with pauses and the occasional drag, points to a raccoon. First light and quick, with rolling sounds inside a wall, points to squirrels. Ground level with digging and an odor that never clears means a skunk. Something seen slowly crossing a yard at night with a pale face is an opossum, which is usually the least destructive visitor you can have. Bats give you evidence rather than noise. Look for a small pile of droppings under one spot on a wall or a garage roof, and a brown greasy mark at the opening itself. Crush a dropping with a gloved hand: guano falls apart into shiny fragments while a mouse dropping stays firm. The identification is not academic in Illinois, where the legal handling of a skunk, a raccoon and a bat differ from one another and set what a permitted operator can offer you.
Why Chicago building stock gives animals so many options
The classic city lot is a narrow building close to its neighbors, a flat or low slope roof with a parapet wall, a wooden back porch, and a detached garage at the alley. Each of those is a distinct opportunity. Parapet and coping lines open as mortar weathers, giving a gap right at the roof edge that is invisible from the street. Back porches sit on posts over an open void, which is an obvious skunk or opossum den once the skirting fails. Detached garages are unheated and unoccupied at night, so an animal can settle in for months before anyone notices, and from there the house is simply the next warmer building. Gangways add a covered travel route between buildings that keeps animals out of sight and next to your foundation the whole way. Because of all this, a proper inspection in Chicago covers the garage and the porch as seriously as the attic, and a quote that only mentions the roof line has probably not looked at the whole property.
What Illinois rules mean for what you can actually buy
Read the state's requirements and the shape of the industry makes sense. A paid operator needs a Class A Nuisance Wildlife Control Permit. A trapped striped skunk must be euthanized. A trapped raccoon must be euthanized or released on the same property. Bats may not be shot, trapped, transported or held except in living quarters situations. The common thread is that moving animals around is not on the menu. That is a public health choice, since relocating animals spreads disease and rarely works out for the animal either, but for you the takeaway is practical: nobody can make your raccoon into someone else's raccoon. So the value of a job sits almost entirely in the exclusion. A trap set without a repair produces a vacancy that fills again, and you pay twice. When you compare quotes in Chicago, look at how many dollars are attached to sealing openings versus how many are attached to trap days. The ratio tells you what kind of company you are talking to.
The Chicago wildlife calendar month by month
March through May is denning. Females need a defensible space and are persistent about getting one, so this is when a weak soffit or a loose vent finally fails. It is also the riskiest time to seal anything, because young may already be inside. June and July are the bat blackout. Colonies are raising pups that cannot fly, and closing a roost then leaves them inside your wall. Anything bat related gets scheduled around this window rather than through it. August and September are the working months. Pups are flying, litters are grown, roof work is comfortable, and schedules are not yet jammed. Exclusion done now is done before the wave. October through December is the rush. Cold pushes everything toward heat, calls spike, and companies book out. Whatever gets in during this stretch will be there until spring, since a warm attic gives an animal no reason to leave. January and February are for evidence gathering. Snow shows tracks up a downspout or along a garage roof, which tells you exactly where to look.
Renters, two flats, and who pays for the repair
The opening is part of the building, so closing it is the owner's responsibility. Chimney caps, vent screens, porch skirting, coping repair and soffit replacement are all structural work, and none of them belong on a tenant. Document specifically rather than generally. Write down dates and times you hear activity, take photos of droppings where they land, and name the location precisely: the rear bedroom ceiling, the porch stairs, the garage roof. A dated written record turns a phone complaint into a work order. In owner occupied two flats and three flats the conversation is often between neighbors rather than with a management company, which usually goes better with an inspection report in hand than without one. Raise a bat differently from everything else. A bat inside a unit is a health matter and should be reported the same day in those terms, not queued behind other maintenance. Mention that paid removal requires a permitted operator, because it steers the building toward hiring properly the first time.