Kane & McHenry County

Noises in the attic at night? Here's what it likely is.

Scratching, thumping or scurrying in the attic or walls? In Kane and McHenry County, attic noise usually comes from a raccoon, squirrels or bats, and less often from flying squirrels. Small, light scratching may be mice or rats, a pest-control job. The time of day helps narrow it down, but droppings, chew marks and the way in are what settle it.

Dusty attic rafters lit by a shaft of light from a vent

Which animal makes which sound?

What you hear	When	Likely
Loud thumping, heavy walking, chattering or growls	Mainly during the day, with comings and goings at dusk and dawn	Raccoon
Scurrying, bumps, muffled rustling	Mainly at night while they're in the nest, quiet once they head out in the morning	Tree squirrels
Activity late at night	After dark	Possibly flying squirrels, the only squirrels active at night
Faint high-pitched chirps or small rustling	Often silent; seen leaving at dusk	Bats
Chirping from a vent or the eaves	Nesting season	Starlings or house sparrows
Small, light, constant scratching	Any time, day or night	Possibly mice, a pest-control job

Source: Wildlife Illinois (University of Illinois Extension and Illinois DNR). Their advice: sound alone is hard to rely on, so always look for other signs.

What signs tell you for sure?

The way in. A small chewed hole in the eaves, fascia or soffit points to squirrels. A big torn opening or ripped shingles points to a raccoon.
Droppings. Raccoons use one spot as a latrine, so you'll find a pile. Bat droppings collect in piles under the roost and crumble into shiny insect bits. Mouse droppings are small, hard and scattered.
The insulation. Paths, tunnels and flattened areas show where something travels.
A new bad smell. Animals living in the attic leave urine and droppings, and if one dies the smell can be strong.
Watch at dusk. To spot bats, watch the roofline from about half an hour before sunset until dark.

What should I do tonight?

Stay out of the attic, and keep kids and pets away from the access.
Don't block any hole yet. In spring a mother may have young inside, and she may chew her way back in.
Not sure it's still in use? Stuff newspaper loosely in the hole. If it's pushed out within three days, something is still using it.
Don't sweep or handle droppings. Avoid stirring up the dust.
If a bat gets into the living space, see bats in the house before you let it go.

Can I trap it myself?

Usually not without a permit. Raccoons, squirrels, opossums and skunks are protected in Illinois. A homeowner needs a Nuisance Animal Removal Permit from the Illinois DNR before setting a trap, and the IDNR only issues one for real property damage or a health and safety concern. Bats in the attic can't be trapped or killed; a colony is excluded instead. A single bat loose in the living space is different: see bats in the house. Poison is illegal on all of these animals.

What does a licensed operator do?

A licensed operator inspects the attic and the outside of the house to find what's there and how it's getting in. Illinois rules require a licensed operator to get your written permission, explain the plan and the estimated cost before starting, and give you a receipt. The lasting fix is sealing the way in once the animals are out.

Questions people ask

Is it a raccoon or a squirrel in my attic?

Timing and weight are the best clues. Wildlife Illinois says raccoon noise (loud thumping, chattering, growls) is heard mainly during the day while the raccoon is denned up, with the adults leaving at night to feed. Squirrel noise is lighter scurrying and rustling, mainly at night while they're in the nest, going quiet once they leave in the morning. A big torn opening points to a raccoon; a small chewed hole points to squirrels.

Why is the noise loudest in the middle of the day?

That fits a raccoon. Raccoons sleep in the den by day, and the young chatter and move around inside. Adults go out at night and may be seen leaving at dusk or returning near dawn.

Can I just block the hole once it leaves?

Not until you're sure nothing is inside, especially in spring when young may be in the attic. A mother cut off from her young may chew her way back in. Stuff newspaper loosely in the hole; if it's pushed out within three days, something is still using it.

Is it safe to clean up droppings in the attic myself?

Be careful. Raccoon droppings can carry a roundworm that is rare but serious, especially for children, and dried bat or bird droppings can carry the fungus that causes histoplasmosis. Avoid stirring up dust and don't handle droppings bare-handed.