Workman uncovered a bat colony with hundreds of bats under a shingle in South America.
Bats are nocturnal and hide from the daylight in cracks and crevices in caves or trees. But they have adapted to a human environment and can roost under shingles, on roofs, under eaves, and (their favorite) inside attics.
Common roosting sites include:
- Gable vents with torn screens
- Eaves and soffits
- Dormers and chimneys
- Areas under broken shingles
- Spaces behind gutters
Bats handle colder weather by either migrating or hibernating. The Mexican Free-Tailed Bat and the Western Red bat are two species that migrate from the U.S. to South America.
How Can You Tell if You Have Bats Under Your Roof?
The most obvious signs are piles of poop or guano. The pellets are small and dark. The elongated pellets are crumbly and turn to dust when touched. It can be used for fertilizer but if you have a bat infestation, do not try to harvest guano. You are putting yourself at risk for histoplasmosis.
You can find where bats are roosting by looking for smudge marks. Bats will crawl from the roost to take over and land. The oils from their fur will leave a mark.

Excluding Bats from Roofs
Residents who want to remove a bat colony from their property need to be careful. Some rare bat species have legal protections to keep people from moving or harming them. Excluding bats in roofs during their breeding season is also illegal in many areas, for good reason.