While the weather is still mild, a quiet competition is already underway on rooflines across the region. Raccoons, squirrels, and other wildlife are scouting for the warm, sheltered spaces they will rely on to survive the coming winter, and your attic, chimney, or the space beneath your deck may be exactly what they are looking for. Across Hamilton, Burlington, and Oakville, Action Pest sees wildlife intrusions climb every fall as animals prepare for the cold, and the homeowners who act before the denning season peaks are the ones who avoid a long, damaging winter tenant.
Why Fall Is Prime Denning Season
For most urban wildlife, the approach of winter triggers an instinctive search for a secure place to shelter. Unlike true hibernators, animals such as raccoons do not sleep straight through the winter, but they do “den up” during the coldest stretches, reducing their activity and relying heavily on a warm, protected space to conserve energy. Squirrels similarly seek out insulated nesting sites where they can wait out the cold. The Government of Ontario recognizes this pattern, noting that small mammals such as raccoons, skunks, squirrels, and bats frequently create issues in residential areas, particularly in urban environments where natural den sites have become scarce.
That scarcity is a big part of the problem. In undeveloped areas, raccoons and squirrels use tree hollows, rock crevices, and abandoned burrows, but mature hollow trees are increasingly rare across suburban Hamilton, Burlington, and Oakville. For an animal navigating an urban landscape, a warm attic that mimics a hollow tree is not just convenient, it is genuinely the best option available, which is why residential structures come under such pressure at this time of year. This seasonal shift is a recurring theme in the pest and wildlife information that helps homeowners anticipate what the changing weather brings.
Where Wildlife Chooses to Den
The spaces wildlife targets for winter shelter are predictable, and knowing them helps you identify your home’s vulnerabilities before an animal does. Attics are the single most sought-after denning site, offering warmth that rises from the living space below, protection from predators and weather, and a quiet, low-traffic environment ideal for nesting. Access typically comes through gaps in soffits, loose or damaged roof vents, and openings where rooflines meet, all of which a determined raccoon or squirrel will test and exploit.
Chimneys are another prime target. An uncapped masonry chimney closely resembles the vertical hollow of a tree, providing a sheltered, enclosed space that female raccoons in particular favour. Ground-level options matter too: the spaces beneath decks, porches, and sheds, along with crawlspaces, offer insulated, wind-protected shelter that skunks and raccoons readily exploit. The insulated void above an attached garage is also a common choice, since it provides a thermal bridge to the warmth of the main house. For any of these wildlife intrusions, the pattern is the same: the animal is looking for warmth, safety, and quiet, and your home may offer all three.
The Damage and Health Risks That Follow
A denning animal is far from a passive tenant. Squirrels tear apart insulation to build nests and gnaw continuously on structural materials and wiring to manage their ever-growing teeth, which creates a recognized fire risk, a danger Action Pest has documented in detail in the context of rodents and wildlife. Raccoons displace and compress insulation, damage vapour barriers, and can compromise roof decking as they establish and expand a den.
The health concerns are equally serious. Raccoon latrines, the communal sites where raccoons repeatedly defecate, can contain the eggs of raccoon roundworm, and a Canadian Medical Association Journal review notes that exposure to contaminated material carries a risk of severe neurological illness, even though such infections remain rare. Bats denning in attics introduce their own risks through guano accumulation. And while rabies remains a consideration with wildlife, the Ontario Ministry of Natural Resources and Forestry reports no confirmed cases of raccoon variant rabies in the province since 2023, thanks to an active vaccine baiting program, so the risk should be understood accurately rather than assumed. Any animal showing unusual daytime behaviour or disorientation should still be reported rather than approached.
Why Timing and Professional Handling Matter
The fall window is critical precisely because it is when animals are actively scouting but have not yet fully settled in. Sealing entry points and addressing vulnerabilities now, before an animal establishes a den, is far simpler than resolving an active intrusion later. It is also safer for the animal, since improper exclusion done after denning has begun can trap wildlife inside or, in the case of nursing young, create both a welfare problem and a decomposition issue within the structure.
This is why professional handling is so important. Trapping and relocating wildlife in Ontario is governed by the Fish and Wildlife Conservation Act, and improper handling carries consequences for both the homeowner and the animal. A professional confirms whether a space is occupied, accounts for the possibility of young, and seals entry points with materials wildlife cannot defeat, rather than simply blocking a hole and hoping. Action Pest approaches winter wildlife pressure with this full picture in mind, resolving intrusions humanely and preventing the recurrence that so often follows a rushed or amateur repair.
Secure Your Home Before They Move In
The animals scouting your roofline right now are looking for a winter home, and the difference between a secured property and a season-long infestation often comes down to acting before the denning season peaks. Because the vulnerabilities wildlife exploits are frequently high up and easy to overlook, a professional inspection of the roofline, attic, and foundation is the most reliable way to find and close them in time. Action Pest can assess your home, identify the weak points, and help ensure the only one settling in for winter is you.
If you would rather keep your attic your own this winter, Contact Action Pest today and shut the door before the scouting turns into settling in.
