Bat prevention: not a swing and a miss

Nov 17, 2023, 13:59 PM by Fred Speer

Did you know that California has an official state bat? In October, Governor Gavin Newsom signed Senate Bill 732, which designated the pallid bat as the official bat of the Golden State.

Many people associate bats with Halloween. But these flying mammals are beneficial to California’s environment, as they feed on insects that threaten vital agricultural crops. Some estimates indicate that bats provide close to a $1 million worth of pest control for California agriculture.

Clark, your local pest, termite, rodent, and yard care expert, would like to make California residents aware that bats also have an unsavory side to them that can leave people unsettled by their presence.

Bat sightings are higher during the fall, as most bats usually leave their maternity roosts — where they raise their newborn pups through the summer — to find a new home for the winter with its more consistently cooler temperatures. Bats prefer diverse types of homes during this time, including caves, cave-like structures in buildings, or hollowed-out trees.

Increased vegetation due to last winter’s higher-than-usual rainfall in combination with higher pest pressure (as bats’ primary diet is insects) also contributes to the increased number of bat sightings.

Bats are a nuisance with their noise, droppings, and urine, which attracts insects. But they are also carriers of such harmful diseases as rabies, which can pose a threat to humans and other animals, including household pets.

Even though bites are rare, bats can transmit rabies. Care should be taken to avoid handling any bats you may encounter. Also consider having your dog or cat vaccinated against rabies, should they encounter a bat.

How bats enter a home

Bats can enter homes through chimneys that lack protective grates or grills, through open windows or doors, under eaves, loose siding boards, openings along the roofline, or utility vents. Their presence can easily go undetected due to their nocturnal habits.

When you notice bats exiting a structure – dusk is the best time to observe this, as bats feed then and are most active – you should look for signs of holes or openings during the daytime.

Bats can also gain access to a structure using holes that other animals, including squirrels or raccoons, have created. Fortunately, bats are not chewers and will not gnaw on electrical wiring like rodents.

You also can identify potential bat access points by looking for stain marks left behind by the bat’s body oils, urine, and droppings. Bat droppings, known as guano, crush easily, and will include shiny bits of undigested insects. Mouse droppings – called scat – lack shiny bits, and bat droppings are never white or chalky like bird droppings.

Bat prevention tips

The best prevention method for bats is to deny them access to your home in the first place. Fall is the best time of year to perform the necessary exclusion work on your home, as younger bats are now able to fly during this season, and will go in search of new roosting sites. It’s much easier to prevent a bat problem than remove one once they have set up shop in your attic.

Any holes more than a half-inch in diameter or cracks that are ¼ inch to 1 ½ inches wide should be sealed with caulk, steel wool, hardware cloth, or a similar material. Screens in windows and doors should also be replaced if torn.

Clark Pest Control has decades of experience protecting homes from bats. Call California’s trusted pest control expert at (800) WE-NEED-YOU (936-3339) or email us at if bats are a problem in and around your home.  

Until next time, the pest management professionals at Clark Pest Control thank you for helping to keep unwanted pests out of your home and yard.