Squirrels keep office hours. If the scratching overhead starts around sunrise, goes quiet in the middle of the day and picks up again before dusk, and the droppings you find are rounded little barrels about 3/8 inch long, you've almost certainly got squirrel droppings in the attic rather than rats.
That usually works in your favor. Squirrel jobs tend to be more localized than rat or mouse jobs, usually concentrated around the nest and the entry hole at the eaves. But squirrels bring in a lot of debris, chew on things they shouldn't, and soak the insulation around their nest with urine.
Squirrel droppings look like small rounded barrels
A squirrel dropping is about 3/8 inch long and roughly 1/8 inch wide, thicker in the middle with blunt, rounded ends, a bit like a tiny coffee bean. Fresh pellets are dark brown to nearly black; they lighten and turn crumbly as they age. In a single group you'll often see a mix of sizes.
How they compare with the other droppings you might find up there:
|
Animal |
Size |
Shape |
Typical pattern
|
|---|---|---|---|
|
Squirrel |
About 3/8 inch |
Rounded ends, thicker middle |
Small scattered groups near the nest and entry |
|
Rat |
About 1/2 to 3/4 inch |
Larger, pointed or capsule-shaped |
Along runways at the edges of the attic |
|
Mouse |
About 1/8 to 1/4 inch |
Thin, pointed ends |
Scattered widely through tunnels in the insulation |
|
Bat |
Similar to mouse |
Crumbles to powder when pressed |
Piles under the roost |
Droppings alone can mislead, so put them together with the other clues before deciding.
Daytime noise is the giveaway
Gray, fox and red squirrels are active by day. They leave the attic in the morning to feed and come back in the evening, which is why you hear them at dawn and dusk. Rats and mice are mostly active at night.
The exception is the flying squirrel, which is nocturnal and often lives in attics in groups. Flying squirrels are easy to mistake for rats because of the night-time noise, and they tend to leave droppings and urine concentrated in a few spots rather than scattered. If you hear activity after dark and find small, rounded droppings piled in corners, flying squirrels are worth considering.
What squirrels do to an attic
Squirrels treat the attic as a nest site with built-in insulation. You'll typically find:
- A bulky nest near the entry, made of dry leaves, twigs and shredded insulation, usually tucked against the eaves or soffit.
- A chewed entry hole at the roofline: the soffit, fascia, gable vent or the gap where a dormer meets the roof. Squirrels often enlarge an existing gap rather than starting from scratch.
- Gnawing on wiring, wood and duct jackets. Squirrels chew to keep their teeth worn down, and exposed wiring in an attic is within easy reach. Chewed wiring is a fire risk, so get an electrician to look at it while the insulation is still out of the way.
- Urine staining and a sharp ammonia smell around the nest, sometimes showing as a stain on the ceiling below.
- Stashed food, such as nuts, acorns and seeds, which can attract other pests.
The health risks are about waste and debris
Squirrels are rodents, so the safe way to handle their waste is the same one the CDC sets out for any rodent. Its rodent cleanup guidance warns against sweeping or vacuuming any rodent waste, since that lifts tiny contaminated droplets into the air you're breathing. Instead, ventilate first, spray the waste with disinfectant or a fresh bleach solution, let it soak, then pick it up wet with paper towels.
Squirrels don't appear among the US hantavirus hosts the CDC names, which are native wild mice and rats such as the deer mouse, white-footed mouse, cotton rat and rice rat, and squirrel droppings get far less attention than raccoon latrines or bat guano. That doesn't make them clean. A nest that has been in use for a couple of seasons is a mass of droppings, urine-soaked insulation, leaves and food debris, and it should be handled with gloves, eye protection and a well-fitting respirator, with the waste bagged rather than carried out loose.
If the attic is older, take a careful look at the insulation itself before disturbing it. Pebbly gray-brown vermiculite may contain asbestos. Our bags, like every insulation vacuum bag sold, are not HEPA rated, so have suspect material tested and handled by licensed abatement.
Timing matters because of the babies
Squirrels commonly raise young in attic nests, and in many areas there are two breeding periods a year, one in late winter or early spring and another in summer. Sealing the entry while young are inside traps them, and the result is usually more damage as the mother tries to chew back in, followed by a dead-animal smell.
Wildlife professionals usually install a one-way exit door over the entry hole, confirm the attic is empty and only then seal it permanently. Trapping and relocation laws for squirrels differ by state, and a call to the state wildlife agency before anyone sets a trap saves trouble later. Cleanup starts after the attic is confirmed empty and the entry is sealed.
What happens to the insulation
Squirrel damage is often concentrated. The nest, the insulation pulled into it and the soiled area around it come out; insulation that is clean, dry and undisturbed a few bays away can usually stay. Remove more when:
- the nest has been in use for several seasons and urine has soaked a wide area,
- flying squirrels have left concentrated latrine areas across the attic, or
- squirrels have tunneled and dragged insulation well beyond the nest.
Squirrel nests add a lot of bulky debris on top of the insulation, which fills bags faster than you'd expect. For eave-area jobs where you can't easily run hose all the way to the work, our PRO-200 small bags can be filled in the attic and carried down through a 22 inch opening. For dry fiberglass or cellulose over a larger area, the PRO-ECO+ Heavy Duty Green bag holds 88 cubic feet with low dust. For long summer days along the eaves, our breathable Cool-Suits coveralls are made for hot attics and fiberglass; around the nest itself, where the urine and droppings are, our microporous Microvek suits are the better barrier.
Order the right bags for the nest and the rest
Squirrel cleanups range from a single nest at the eaves to a full attic strip-out, and the bag count varies just as much. Run the attic through our free bag calculator, browse the full range on our insulation vacuum bags page, and call us at 404-354-6268 if you'd rather talk it over. Someone picks up 24/7, and RAM orders go out the same day with free shipping anywhere in the US.
Frequently Asked Questions
Do squirrels use one spot as a bathroom in the attic?
Gray squirrels tend to scatter droppings around the nest and along their routes rather than using a single latrine. Flying squirrels are more likely to use a few communal spots, which is one way to tell them apart.
Will squirrels leave the attic on their own?
Not reliably. An attic with a warm nest and an easy entry is a year-round home, and squirrels that leave to feed come back every evening. They need to be excluded and the entry repaired.
Can squirrel urine come through the ceiling?
Over time it can. Urine soaks through insulation and into the drywall below, leaving yellow or brown stains on the ceiling and an ammonia smell in the room. Any stained drywall should be checked once the insulation above it is removed.
Is it safe to seal the hole once the attic goes quiet?
Not on silence alone. Squirrels can be out feeding during the day, and young may still be in the nest. A one-way exit door, a few days of monitoring and a check for babies should come before the hole is sealed.
How much insulation usually has to come out after squirrels?
Often less than after rats or mice, because squirrels concentrate their nest and mess near the entry. A single-season nest may only need the surrounding few bays removed, while long-term or flying squirrel infestations can mean a full strip-out.