Bats

Mexican Freetail bat (Tadarida brasiliensis) found on campus

All common bat species found in North America are nocturnal, and insectivorous. They are most beneficial in keeping down insect populations. It is estimated that one bat can eat as many as 3,000 insects, including mosquitoes, in a single night.

Most bats give birth to single baby, but twins do occur occasionally. Babies are born in early to late May, but the young are unable to fly until mid-summer. When they are very tiny the young cling to the mother as she hunts for food, but as they grow and become heavier they are left behind in the nursery colony.

When roosting, bats hang upside-down by their hind limbs. Roosting sites vary between species. Some roost in trees, while others roost in caves. Sometimes bats will take up residency in a building. Attics, building eaves, unused chimneys, under porch roofs, and hollow walls all make nice bat roosting sites. Bats can squeeze through very small or narrow openings, so for purposes of bat management, gaps as small as 1/4 x 1 1/2 inches or holes 5/8 x 7/8 inch, should be given attention.

Although the rabies virus occurs in less than one half of one percent of all bat populations, bats are more commonly associated with transmitting rabies to people more than any other animal. Nonetheless, bats do sometimes carry rabies and sick bats should not be handled without protection

Living With Bats

Bats are most beneficial in controlling flying insects like mosquitoes. Slowly people are learning to appreciate bats and their role in the ecosystem. Because of the unnecessary destruction of bats and loss of habitat, many people are installing bat boxes. There are many resources available for constructing bat houses and they can be purchased through gardening catalogues. Once a bat box is installed, it could take from a couple of weeks to a couple of years before bats take up residency.

• Bat houses must be secured at least 12 to 15 feet above the ground. They cannot tolerate temperatures above 90 degrees, so the boxes should be placed where they will receive morning, but not afternoon sun.
• Bat houses should be located near a water source like marshes or ponds (wherever there is an abundant insect population).

When bats take up residency inside dwellings where humans are present it is important to determine whether there is damage to the structure (from excreta accumulations), or if their presence poses a health risk. If intervention is warranted:

• Timing is critical. There is an optimal period for removing bats because the concept of bat conservation must also be considered. Whenever possible, bat removal should be undertaken after babies are weaned and able to fly. From mid to late August to May is the optimal period for treating areas for bats. Prior to this time, exclusion treatments will result in the unnecessary death of baby bats.

Contact Animal Control (459-2231) for ideas or suggestions.

Sick Bats

• If you find a bat that appears sick, DO NOT TOUCH IT. Instead call the campus Animal Control Officer. You may cover it with a container such as a coffee can until the Animal Control Officer arrives.
• If you decide that you cannot wait and the bat must be moved, use extreme care. Wear heavy leather gloves and cover all exposed skin for protection.
• If you are accidentally bitten by a bat, make sure you save the bat for examination. Immediately wash the wound with soap and water and seek medical assistance immediately.
• State and local laws require that any animal bite must be reported, and any close contact with a bat should be reported because of the risk of rabies.

Bats in Buildings

When doors or windows are left open, bats will sometimes fly into buildings and become trapped. If this happens:

• Do not attempt to pick up the bat.
• Isolate the area by closing off doorways and leave a window open. They will usually find their way out.
• If they do not find their way out, or the windows cannot be left open for security reasons etc., place a large jar or coffee can over the bat. Wearing gloves, slide a piece of stiff paper under the jar or can. If you are sure it is not sick, release it outdoors. If you think the bat may be sick, call the Animal Control Officer at 459-2231.

Additional Sources

Frantz, S. 1986. "Batproofing Structures with Birdnetting Checkvalves." Proceedings of the 12th vertebrate conference, University of California at Davis, (p 260-268).

Kern, W.H., Jr., J. Belwood, and P.G. Koehler. 1993. "Bats in Buildings." Fact sheet ENY-272. Florida Cooperative Extension service, University of Florida.

Lee, C., and F.R. Herderson. 1992. "Bats: Urban Wildlife Damage Control." Publication L-855. Cooperative Extension Service, Kansas State University, Manhattan, KS.