How Do I Evict or Exclude Bats From My Home?

If you are trying to remove bats from your home or a building, exclusion is the only legal and appropriate method. But you cannot use exclusion during maternity season, which is April 16 through August 14.  Common pest control methods such as poison, relocations and fumigants are illegal to use on bats in Florida and also ineffective.

Remember: It is illegal to exclude or remove bats during maternity season!

What is bat exclusion?

Bat exclusion is a multi-step technique where all potential bat entry and exit points in a building are identified. One-way exit devices are installed to allow bats to leave the structure but not re-enter. Finally, all potential bat entry points are permanently sealed to prevent re-entry by bats.

Step by Step Instructions for Completing a Bat Exclusion

This exclusion information is based on instructions from the Florida Bat Conservancy, Bat Conservation International, Bat Conservation and Management, and Fly By Night Inc.

Step 1. Find the entry points for bats.  A closer look during daylight at a hole or crevice bats are using will likely reveal staining around the edges from their body oils and a scattering of bat droppings on the wall.   After locating potential emergence point, watch for bats emerging from the building. Bats emerge from their roost shortly after sunset, so it is best to observe the building from sunset until dark. If there are multiple emergence points, watch different areas on different nights, or have other people assist you.

Step 2.  Bat-proof all other openings.  Carefully survey the exterior of the building during the daytime.  Now that you know which holes or crevices the bats are using, you can seal up any other areas not currently being used by bats where they might get back in. Entryways currently being used by bats must remain open until the end of the maternity season, and until the exclusion has been conducted.  Once the exclusion is conducted, the bats will look for other entrances back into the building.  Bats can enter any hole that is ¾ inch in diameter or any crevice of 3/8 inch or more.

Step 3.  Install exclusion devices.  Several exclusion methods have been developed over the years, and no one method is best for every situation.  Methods cited here are based on recommendations from the Florida Bat Conservancy, Fly By Night Inc., Bat Conservation International or IFAS/University of Florida.  



Step 4.  Allow time for the bats to leave.  Before removing the netting or tubing, the area should be observed carefully at emergence time to make sure no bats are exiting. Florida regulations require the netting or tubing be left up for at least four warm nights without rain or high winds to assure all of the bats have left. Bats tend not to forage on cold or rainy nights, so if the weather turns bad, it will be necessary to extend the exclusion an additional four consecutive nights.  If bats are still coming out after four nights, then they have either found another way back in or the exclusion system is not working and needs to be revised. If exclusion materials become loose or detached, the bats will be able to re-enter, so make sure it remains secure throughout the process. Bats will be checking continually to see if they can re-enter their roost. 

Step 5.  Permanently seal the openings.  After the bats have been successfully excluded, the netting or tubes can be removed during the day and the openings permanently sealed. Do not leave the netting down without sealing the openings, or the bats will move back in the following night. If the openings cannot be sealed immediately, the exclusion devices may be left up longer, but there is a risk that wind, storms or failure of fasteners could allow the bats to re-enter. Another approach is to take the netting down and temporarily cover the openings with plywood or hardware cloth until permanent repairs can be made.

Step 6.  Cleanup.  If a colony of bats has been in a roost for a long time there will likely be an odor and an accumulation of bat guano. In most cases, the odor is actually from the scent gland, not the guano, of Brazilian free-tailed bats, a bat commonly found in Florida buildings. This odor should disperse shortly after the bats are gone. Bat guano is made up of undigested insect particles and usually can be left undisturbed without concern for human health, if it is in a dry area of the building that is not used or is inaccessible. Unfortunately, bat guano left undisturbed over time can attract insect pests such as cockroaches, so should be removed if the threat of pest infestation is possible. When disturbing the guano, it is important to take precautions due to a fungus that can grow in soil enriched by bat droppings that may cause a respiratory illness known as histoplasmosis. Cases of histoplasmosis due to bat guano in a building have never been reported in Florida; they have only been reported from bats in a cave environment. However, the Centers for Disease Control recommends wearing respirators whenever an individual is in a confined space with bat guano. 

Step. 7 Bat Houses.  Once bat are displaced, they need to find another location to serve as a roost.  Providing a bat house nearby before the exclusion begins can provide a potential roosting location for displaced bats. If you wish to erect a bat house, it is a good idea to determine the flight paths of the bats as they exit the building. Once the flight path is known, it is best to erect the bat house while the original roost is still active and to locate it in the flight path of the bats, or as close to the existing roost as possible. This way the bats will see the option exists and be aware of its presence. Experts also recommend that bat houses be painted tan or brown and be erected on a pole or building and not a tree to increase the amount of sunlight the bat house receives. Additional information regarding bat houses can be found on the Bat Conservation International External Website website. After the exclusion begins, you may want to monitor the bat house to determine if bats are relocating to it. Remember however that bat houses will not always attract bats. Also, putting up a bat house is not a substitute for exclusion because bats are highly unlikely to leave an occupied building to begin using a bat house unless forced out of that building.

FWC Facts:
Adult Florida bass usually eat crayfish and other fish, but on rare occasions eat snakes and birds.

Learn More at AskFWC