- Author: Belinda J. Messenger-Sikes
Are bats good for the environment or are they pests? How about both? Almost all of the 25 species of bats in California eat lots of flying insects during their night flights, making them an important part of the ecosystem. But when they roost in buildings such as your home, they can become pests.
Bats roosting in outbuildings away from dwellings aren't much of a problem. Some people even place bat houses on their property to attract bats for assistance with pest control. But a colony of bats in your attic is cause for concern. Bats can spread human diseases like rabies and their droppings (called guano) can make a smelly mess.
If bats are a problem in your home, UC IPM has useful information to help exclude these unwelcome visitors. UC IPM's free publication Pest Notes: Bats was updated in March 2021 by A. Michael. Glassey, Medical Entomologist at the U.S. Army National Training Center in Fort Irwin, CA, and John F. Karlik, UC Cooperative Extension Advisor in Kern County. The publication describes public health concerns associated with bats living near humans and detailed management techniques for dealing with bats roosting in structures.