Why Mice & Rats Are Targeting Your Foundation

As the first true frosts of November 2025 hardened the ground in Hamilton, Burlington, and Oakville, a silent migration began. While larger wildlife like raccoons are settling into their winter dens, Southern Ontario’s rodent population is facing a survival crisis.

At Bad Company Wildlife, November is the month we see a dramatic spike in scratching-in-the-walls calls. As outdoor food sources vanish and temperatures drop, mice and rats don’t just stumble into your home; they actively scout for the heat signatures escaping from your foundation.

Dime-Sized Mouse Entry

It is a biological marvel, and a homeowner’s nightmare, that a standard House Mouse can compress its ribs and squeeze through a gap no wider than a pencil (approximately 6-7mm).

During our November inspections, we often find that the primary entry points aren’t on the roof, but at ground level:

• Weep Holes: These necessary gaps in your brickwork are designed for ventilation, but they are front doors for mice.
• Utility Penetrations: The spots where your A/C lines, gas pipes, or internet cables enter the house often have small gaps in the sealant. In the cold November air, these gaps leak warm attic air that rodents follow like a map.
• Garage Door Corners: Rubber seals often warp or tear at the corners, allowing rodents to enter the garage and, from there, access the main house through the utility room.

The 2025-26 Rat Surge in Ontario

While mice are a perennial issue, 2025 has seen a documented increase in rat activity in suburban areas like Hamilton Mountain and Oakville. Urban development and milder-than-average autumns have allowed rat populations to reach record highs.

Unlike mice, rats are neophobic. That means they’re terrified of new things. This makes DIY trapping in November incredibly difficult. If you set a trap and miss, that rat will likely never approach a similar trap again. This is why professional rat removal focusing on exclusion (sealing them out) is the only permanent solution.

Our No-Poison Pledge

In November, many homeowners are tempted to throw bait blocks or poison into their attics. At Bad Company Wildlife, we strictly avoid this approach, and for good reason.

1. The Odour Problem: A poisoned rodent doesn’t go outside to die. It crawls into the deepest, warmest part of your wall, often near a furnace duct. As the heat runs in November, the smell of a decomposing rodent will permeate your entire home.
2. Secondary Poisoning: Under Ontario’s 2025-2026 wildlife guidelines, we are seeing an increased awareness of secondary poisoning. If a poisoned mouse is caught by a local hawk or an outdoor pet, the toxins move up the food chain.
3. The Empty House Effect: Killing the resident mice does nothing to fix the hole they used to get in. Within weeks, the scent of the old nest will attract new rodents, and the cycle repeats.

Health Risks

Rodents in your home are a serious health concern. In Southern Ontario, Public Health monitors rodents for several pathogens.

• Salmonellosis & Leptospirosis: Transmitted through contact with rodent urine or droppings, often found in kitchen pantries.
• Hantavirus: While rare, this can be contracted by inhaling dust contaminated with mouse droppings. Which is a major risk when homeowners try to sweep up old nesting material in the attic.
• Parasite Migration: Mice and rats carry fleas, ticks, and mites. When the rodent is removed (or dies), these parasites move into the carpet and furniture in search of a new host.

The Bad Company Search & Seal Process

Our mouse removal process for November focuses on total home protection:

1. Thermal Perimeter Scan: We use thermal technology to find heat leaks that are attracting rodents.
2. Chew-Proof Exclusion: We don’t use foam or wood to patch holes. We use galvanized steel mesh and specialized sealants that rodents physically cannot chew through.
3. Interior Mitigation: We safely remove the current population using humane, non-toxic methods.
4. Sanitization: We treat the affected areas to neutralize pheromones, breaking the trail for future invaders.

A Homeowner’s November Checklist

Before the first major snowstorm of the year, take 15 minutes to check these three areas:

• The A/C Line: Ensure the foam insulation at the point where the copper pipe enters your brick is intact. If it’s chewed, you have an active entry point.
• The Door Sweeps: Turn off the lights in your garage. If you see daylight under the door, a mouse can see the warmth.
• The Kitchen Kickplates: If you find black rice (droppings) under your sink or behind the stove, the incursion has already moved past the foundation.

Secure Your Home for the Winter

Whether you are in Hamilton, Burlington, or St. Catharines, don’t wait for a single mouse to become a colony. Rodents breed exponentially; a small problem in November can become a full-blown infestation by January. Stop the scratching today. Contact Bad Company Wildlife for a comprehensive rodent removal and foundation sealing.