As the autumn leaves settle across Hamilton, Burlington, and Oakville, a quiet yet significant shift is underway in the attics of Southern Ontario. While homeowners are focused on winterizing their gardens, our local bat populations are preparing for a biological event known as torpor.
At Bad Company Wildlife, October is one of our busiest months, but it is also the month of the Hard Deadline. Due to the unique biology of bats and the strict environmental protections in place across the province, the window for bat removal effectively slams shut on October 31st.
If you suspect you have bats in your attic, understanding this timeline is critical to avoiding a legal and structural nightmare that could last until the following June.
Why Bats Are Specially Protected
In Ontario, bats aren’t just another pest. Under the Fish and Wildlife Conservation Act, most of our local species, including the Little Brown Myotis and the Big Brown Bat, are classified as Specially Protected Mammals. Furthermore, the Little Brown Myotis is listed as an endangered species under the Endangered Species Act.
The Law: It is illegal to harass, capture, or kill bats in Ontario without a permit. More importantly for homeowners, it is illegal to perform exclusion (sealing them out) during the hibernation period.
If a colony is sealed inside an attic once the temperature drops, they cannot leave to find food or water. They will eventually perish inside your walls, leading to significant biohazards and odour issues, or they will crawl downward into your living space in a desperate attempt to find an exit.
The Hibernation Deadline Explained
Bats are insectivores. Once the first hard frosts hit the Golden Horseshoe in late October, their food source vanishes. To survive the Canadian winter, bats enter a state of torpor, a deep sleep where their heart rate drops from 1,000 beats per minute to just 20, and their body temperature plummets to match the surrounding air.
Once a bat enters this state, they are physically incapable of flying out of a one-way door system. At Bad Company Wildlife, we follow the ethical guidelines set by Bat Conservation International, which mandate that exclusions should only occur when bats are active and able to survive the relocation. In Ontario, this means that once we hit November 1st, we typically stop all exclusion activities until the spring thaw in May or June.
Signs You Missed the Window
If you didn’t secure your home in August or September, you may begin to notice winter activity. Bats do not sleep soundly for 6 months straight; they occasionally wake up to move to a warmer part of the attic or to find a drop of water.
- The Scrubbing Sound: Unlike the heavy thumping of raccoons or the frantic scurrying of squirrels, bats make a light scratching or scrubbing sound. This often happens inside wall voids near chimneys or in the corners of the attic.
- The Scent of Guano: Bat droppings (guano) have a distinct, pungent ammonia smell. As the heat stays on in your home during November and December, it can bake the guano in the attic, making the scent more noticeable on the upper floors.
The Risks of DIY Winter Sealing
We often see homeowners attempt to plug the hole in November after seeing a bat. This is the most dangerous move you can make.
- The Descent: When a bat is trapped and wakes up from torpor, it will follow the warmth of your home. This leads them down through pot lights, cold air returns, and unfinished basements.
- The Biohazard: If a colony of 20–50 bats dies inside your walls because they were sealed in, the resulting decomposition is a major health risk. This often requires the removal of drywall and insulation to remediate the scent and the beetles that are attracted to the carcasses.
- White-Nose Syndrome (WNS): Ontario’s bat populations have been devastated by White-Nose Syndrome, a fungal disease that has killed millions of bats across North America. Illegal or improper exclusion adds unnecessary stress to the survivors, potentially wiping out a local colony that is vital for our ecosystem (a single bat can eat up to 1,000 mosquitoes an hour).
What We CAN Do During the Winter Months
If you discover a bat infestation after the October 31st deadline, you aren’t completely out of luck. While we cannot perform a full exclusion, Bad Company Wildlife offers a Winter Bat Assessment:
- Interior Sealing: We can identify and seal entry points inside your home (such as gaps around attic hatches or light fixtures) to keep bats in the attic and out of your bedrooms.
- Property Inspection: We can map out the exterior entry points and provide a quote and a scheduled first-in-line date for the spring exclusion window.
- Safety Consultation: We educate homeowners on what to do if a bat accidentally enters the living space and how to handle it safely to avoid exposure to rabies.
Plan Ahead for 2026
The best time to handle a bat problem is August and September, right after the pups have learned to fly but before the hibernation deadline. However, if you are hearing those light scratching sounds this October, you have only a few weeks left to act.
Whether you are in St. Catharines, Hamilton, or Oakville, our team is committed to humane, legally compliant bat removal.
Don’t wait until the deep freeze. Contact Bad Company Wildlife today to see if we can still secure your home before the October 31st cut-off.
