A squirrel infestation typically announces itself with scratching and scurrying sounds in your attic or walls, especially during early morning hours. Squirrels are daytime creatures, so unlike rats or mice, the noises tend to quiet down at night. If you’re hearing activity overhead during daylight and finding light brown, raisin-shaped droppings, you’re almost certainly dealing with squirrels rather than other rodents.
How Squirrels Get Inside
Tree squirrels are the species most likely to move into residential structures, and they’re remarkably resourceful about finding a way in. Common entry points include roof vents, chimneys, broken windows, knotholes, and construction gaps under eaves or gables. Fox squirrels can even climb vertical brick or masonry walls as long as the surface has some texture to grip.
Once inside, squirrels don’t just settle in quietly. They’re rodents, meaning their teeth grow continuously and they need to chew to keep them worn down. That chewing habit is what makes them destructive houseguests. They’ll gnaw through wood, insulation, plastic piping, and, most dangerously, electrical wiring. Damaged wiring can overheat and spark a fire. One fire safety company reported mitigating over 50 fire hazards caused by squirrels in a single year. A squirrel making contact with transformer equipment in Austin, Texas left nearly 1,000 people without power.
Signs You Have an Infestation
Beyond the sounds and droppings, look for these indicators:
- Chew marks on wood trim, fascia boards, or roof edges, particularly near potential entry points
- Tiny footprints in dusty areas of your attic that look like miniature human feet
- Damaged insulation that’s been torn apart, compressed, or nested into
- Exterior holes in soffits, eaves, or where utilities enter the house
- Acorn caches or nutshells accumulating in corners of attic spaces
Squirrel damage to exterior wiring is often invisible from the ground because it happens high up on overhead lines. If you’re experiencing unexplained voltage fluctuations or brownouts, animal damage to your utility lines is worth investigating with your power company.
When Infestations Happen
Squirrels breed twice a year, in late winter and again in late summer. After a 44-day gestation period, they give birth in spring and late summer. This means the peak months for discovering an infestation are March through April and late August through September. The most common reason a squirrel enters your attic is to give birth in a warm, protected space.
This timing matters for removal. If you seal up entry points while babies are still inside, you’ll trap dependent young that can’t survive on their own. A mother squirrel separated from her litter will also cause significant additional damage trying to chew her way back in. Any removal effort needs to account for whether young might be present.
Health Risks From Squirrels
Squirrels carry a range of diseases that can spread to humans, mostly through contact with droppings, urine, or contaminated materials. The bacteria that causes tularemia can be transmitted through direct contact, tick bites, or even by breathing in particles from dried feces or urine. Leptospirosis and hantavirus spread similarly: infected squirrels show no signs of illness but shed the pathogens in their urine, and people get infected through inhalation, ingestion, or skin contact with contaminated material.
Salmonella, E. coli, and giardia are all transmitted through accidental contact with squirrel feces. Squirrels also serve as a reservoir for Lyme disease, hosting the ticks that carry the bacterium to humans. If you’re cleaning up after a squirrel infestation in your attic, wear a respirator and gloves. Sweeping or vacuuming dry droppings can aerosolize dangerous pathogens.
Why One-Way Doors Often Fail
A common recommendation for wildlife removal is installing a one-way exclusion door: you seal every entry point except one, install a device that lets the animal leave but not return, and wait. This works well for many species, but professional wildlife removers generally avoid using one-way doors for squirrels. The reason comes back to their chewing ability. A squirrel that considers your attic its home will try anything to get back in. If the one-way door blocks its main entrance, it simply moves over a foot or two and chews a new hole.
One-way doors can work on structures with exteriors that squirrels can’t chew through, like brick, solid block, or metal-clad buildings in good repair. On wood-sided or vinyl-sided homes, which make up the majority of cases, they tend to create more damage than they prevent. The squirrel doesn’t give up. It escalates.
What Actually Works for Removal
Effective squirrel removal combines trapping with thorough exclusion work. A professional will inspect for all entry points (not just the obvious one), trap or evict the animals, and then seal every gap with materials squirrels can’t chew through, typically galvanized steel mesh or metal flashing. The timing needs to avoid birthing seasons unless young have been confirmed absent.
For a single squirrel, professional removal runs $200 to $300. A small group costs $300 to $450, a large nest $450 to $600, and a full infestation starts at $600 and goes up from there. Location matters too: attic removal ranges from $280 to $920, while a ceiling infestation (where squirrels have worked their way between floors) can cost $775 to $1,550 because of the access difficulty. Most homeowners pay between $250 and $450 total, with an average around $300. An initial inspection alone typically runs $100 to $150.
Deterrents and Prevention
Capsaicin, the compound that makes hot peppers burn, has some scientific support as a squirrel deterrent. In a Cornell University study, coating birdseed with capsaicin at 40,000 Scoville Heat Units reduced the amount of seed squirrels consumed by 69% to 80% at two of three test sites. Squirrels that did visit spent roughly half as long feeding. Birds were completely unaffected because they lack the receptors that detect capsaicin. However, at one test site, squirrels actually ate more of the treated seed, suggesting results can be inconsistent. The treated seed also had no effect on chipmunks.
Capsaicin sprays can help protect specific targets like bird feeders or garden plants, but they won’t solve an infestation. Ultrasonic deterrent devices are widely marketed but lack strong scientific evidence for long-term effectiveness against squirrels.
The most reliable prevention is physical exclusion: trimming tree branches at least 6 to 8 feet from your roofline, installing metal mesh over vents and chimney openings, and repairing any gaps in soffits, fascia, or eaves before squirrels discover them. Pay special attention to construction gaps under eaves and gables, which are the entry points squirrels exploit most often.
Legal Considerations
Trapping and relocating squirrels is regulated differently in every state. In Texas, for example, landowners can remove nuisance wildlife on their own property without a license, but relocating the animal requires authorization from the state wildlife department and permission from the property owner where you plan to release it. Monthly reporting on the number and type of animals captured is also required. Possessing or selling certain live wildlife can be a misdemeanor.
Other states have their own rules, and some protect certain squirrel species entirely. Before setting traps yourself, check your state’s wildlife agency website for current regulations. Professionals are already licensed and insured for this work, which is one reason hiring one often makes more sense than a DIY approach, especially when babies might be involved.