Depending on where you live, bat activity can vary a lot throughout the year.
Here in the mountains where I live, bats typically show up from late spring through late October. Once temperatures drop, they usually migrate or move to winter roosting sites.
But during those active months, they can become a serious nuisance if they get into your attic or roofline.
Bats leave behind large amounts of guano (droppings) and heavy urination, which can create strong odors, staining, and contamination in insulation and attic spaces. It’s definitely something you don’t want building up in your home.
🔎 One Simple Trick to Identify Bat Droppings
Here’s a little trick most people don’t know.
If you’re inspecting an attic or roofline and you find droppings, you can usually tell the difference between bat droppings and rodent droppings pretty quickly.
Put on a glove or some kind of protection and gently press one of the droppings.
• Bat droppings will crumble into dust when you press them.
• Rodent droppings stay hard and solid.
Bat guano contains crushed insect shells, so it breaks apart easily.
Rodent droppings are much firmer and won’t crumble like that.
🏠Finding the Entry Point
Once you confirm you’re dealing with bats, the next step is inspecting the exterior of the structure.
In my experience, 9 times out of 10 the entry point is above eye level.
Common locations include:
• roof peaks
• fascia boards
• soffit gaps
• roofline joints
• attic vents
Occasionally an entry might be closer to eye level, but it’s pretty rare.
Bats prefer higher points where they can drop down and take flight easily.
đź”§ Installing a One-Way Bat Exclusion Cone
Once the entry point (or multiple entry points) are located, the proper way to remove bats is exclusion — not trapping.
This means installing a one-way bat cone or exclusion device directly over the hole they’re using.
The cone allows bats to exit the structure but prevents them from getting back inside.
Bats are extremely active around sunset, so once the cone is installed, they’ll usually leave the structure that evening to feed.
In most cases:
• The majority of bats exit the first night
• The device stays up about one week to ensure the colony clears out
During that week you can listen for activity in the attic. When the noises stop and there’s no more movement at dusk, the structure is usually clear.
đź”’ Final Step: Permanent Sealing
Once you’re confident the bats are gone, the cone is removed and the entry point needs to be sealed very securely.
Bats can fit through surprisingly small openings — almost like flying mice.
My typical sealing method includes:
• coarse steel wool packed into the gap
• weather-proof exterior caulking
• metal flashing or sheet metal reinforcement if needed
This prevents bats from reopening the same spot later.
Any nearby gaps should also be sealed because bats will often try to find another opening close to the original one.
🛠Bat exclusion is one of the most satisfying wildlife jobs to complete when it’s done properly.
More real-world wildlife exclusion methods coming soon inside Backcountry Pest Academy.