Tamarack Wildlife Rehabilitation & Education Center

Bat (Rabies Vector Species)
Order Chiroptera

Bats are the only group of mammals that can fly. They are nocturnal but can often be seen foraging at dusk. In recent years the public image of bats has changed. Though once feared by humans, bats are better appreciated now that humans have come to realize these animals’ ecological importance. Among other things, bats serve a valuable role in controlling insect pests.

Habitat: Individual species tend to have specific habitat requirements. Almost all bats migrate.

Diet: All common North American bats feed on insects. They detect their prey using echolocation. This special adaptation allows a bat to emit a high frequency sound, which is reflected back to the bat, identifying the location of its prey.

Public Health Issues Associated with Bats

• Bats are commonly associated with rabies, but the incidence of this disease in bat populations is estimated to be less than half of 1 percent.

• If a bat must be handled for any reason, leather gloves should be worn to protect the hands since bats may bite.

• Large accumulations of bat droppings harbor histoplasmosis fungi spores and should be approached with care. If it is necessary to be in areas with large amounts of bat droppings, wear boots, use a mask, and make sure to wear disposable gloves (discard them after use). Properly bag clothing for washing.

Problems Associated with Bat

• Small openings (one-half inch or greater) high on houses, around chimneys, and at the union of dormers with roofs or at loose siding can all provide access for bats to enter buildings. Bats roosting in houses often go unnoticed for years.

• Sometimes a single bat may be found inside a house and can be observed flying around a room in the early evening, landing on curtains or furniture. In this case, getting the bat out of the house is a high priority.

Solutions

• Do not panic if you encounter a bat trapped inside a house or discover bats in an attic. Trapped bats can be released outside and attic colonies can be removed humanely and effectively. The best strategy for excluding a bat colony from a building is to allow the bats to leave on their own and then deny them re-entry.

All outside entrances that the bats may be using should be located. Well-used openings will often be discolored on the outside from the bats’ body oils.

All except the largest or most obviously used hole should be sealed.

This last opening can be fitted with netting after bats have left for the night. Not all members of the bat colony will leave to feed on any given night, so this process will have to be repeated.

An alternative measure is to fit the last opening with a one-way bat check valve. This consists of netting draped over the entrance but left open at the bottom. Bats will exit, crawl down the side of the house, and leave, but they will not be able to return.

After you are certain that all the bats are gone, remove the netting and seal the last opening.

Additional Notes

• Do not attempt to prevent bats from returning to an attic or other roost in the summer or early fall. Babies are born and raised at this time.

• Another option in trying to rid an attic of bats is to put a bright light in the space, leaving it on 24 hours a day, or putting a radio in the space and playing loud rock music. The bright light and the loud music can also be used together.