Flying squirrels vs other squirrels in an attic: what signs help?

You are sitting downstairs reading a book late at night when you hear a soft, rapid scurry right above your ceiling, followed by a light thud. It sounds almost like a golf ball dropped on the floorboards. If this happens at two in the morning, you are dealing with a very different tenant than if the same noises woke you up at dawn. Figuring out whether you have flying squirrels or standard tree squirrels in your attic comes down to understanding their daily habits, because catching sight of them scurrying around inside dark structural spaces is nearly impossible.

People often assume that all squirrels behave the same way, but their schedules are entirely different. Flying squirrels are strictly nocturnal, acting like midnight shift workers who only clock in after complete darkness. Gray, fox, and red squirrels are diurnal, meaning they wake up with the sun and wind down around dusk, much like a morning commuter heading out early. If your ceiling stays quiet until midnight and then turns into a miniature bowling alley, you can usually rule out the larger daytime species.

Beyond the clock, you have to look at how they treat your roof. Tree squirrels are heavy-bodied and aggressive chewers, while flying squirrels are smaller and prefer to exploit whatever architectural shortcuts are already available. Understanding these clues stops you from wasting time on the wrong fixes.

Timing is your first and most reliable diagnostic tool, but you can usually confirm the species by looking at the physical evidence left behind. Start with the noise itself. Flying squirrels make light, rapid scampering noises accompanied by soft thumping and occasional social chirping. Tree squirrels make a much heavier, deliberate sound, often featuring loud chewing, vigorous scratching on wooden beams, and heavy running that vibrates through the drywall.

Next, look at the droppings, but do so with a flashlight and without touching anything. Flying squirrel scat consists of small, smooth, oblong tubular pellets, usually measuring between three and six millimeters, and they tend to concentrate these droppings in communal latrines near their nesting spots. Tree squirrel scat is noticeably larger, usually eight to twelve millimeters long, and gets scattered broadly across attic insulation and along travel pathways rather than piling up in one tidy spot.

You can also check the entry points on your roof. Flying squirrels usually squeeze through existing gaps down to half an inch wide, such as unscreened ridge vents, loose soffits, or construction gaps around rake boards. Tree squirrels actively create or enlarge their doorways by gnawing through wooden fascia boards, vinyl siding, or rotted roof decking. Their entry holes are round or oval, measuring an inch and a half to three inches across, and they often leave dark rub marks from their fur oils around the edges.

If you are still wondering which animal is up there, you can set up a simple movement test before sealing anything up. Wedge a piece of crumpled newspaper loosely into the suspected entry hole, or tape a strip of duct tape across the gap. Check it every morning for three consecutive days of clear weather. If the paper stays put, the opening is currently inactive. If it gets pushed out, animals are still using that doorway. You can also dust a thin layer of food-grade flour on a piece of cardboard near attic travel paths to check the track geometry. All rodents have four-toed front feet and five-toed hind feet, but a tree squirrel leaves a hind print roughly an inch and a half long, while a flying squirrel leaves a print under one inch.

Once you identify which type of squirrel is up in your roof space, you have to resist the urge to grab a can of expanding foam or a tube of caulk and seal the holes immediately. Sealing an active entry point without checking the interior often traps adults or flightless young inside the walls, leading to desperate chewing through interior drywall, terrible odors, and eventual animal mortality.

You need to verify that the attic is completely empty using your movement indicators over a few days. Once you confirm the animals are out foraging, the permanent solution is physical exclusion rather than chemical deterrents. Commercially sold ultrasonic gadgets and chemical repellents rarely work for long, because animals quickly get used to static noises or just move to a different corner of the attic. Think of an ultrasonic repeller as a noisy alarm that someone learns to ignore, whereas structural exclusion is like installing a deadbolt lock.

Seal all inactive gaps measuring a quarter of an inch or larger using heavy-duty galvanized hardware cloth or sheet metal flashing. Prune any tree branches back at least six feet from your roofline to eliminate the jumping launch pads that tree squirrels love to use.

There are moments when a do-it-yourself approach stops being practical and starts becoming a hazard. If you discover signs of raccoons sharing the attic space along with the squirrels, or if you find heavy accumulations of droppings that might harbor dangerous parasites or fungal spores, bring in a professional. Raccoon roundworm eggs, for instance, require specialized high-heat cleaning protocols because standard household bleach fails to kill them.

You should also call a licensed wildlife control operator if the entry points are located on steep three-story rooflines, or if you are dealing with an active maternity season during spring or late summer when young animals might still be flightless inside the wall voids. Furthermore, if anyone in the household suffers a direct bite or scratch from a mammal in the attic, contact a medical clinician or public health authority immediately to evaluate potential rabies exposure.