Where do Houston bats come from?

Although there are 11 species of bats that either reside or migrate through Houston, most bats that people will encounter in their Houston home or property are Mexican Free-Tailed bats. As the name suggests, they migrate back to Mexico to ride out winter in caves. However, if they find a suitable temperature/environment in one of our man-made structures they may not migrate and instead reside in Houston year-round.