Illinois Natural History Survey - University of Illinois

How to Help Bats



Jen Mui


Over 25% of bat species are threatened or endangered, and in Illinois, all bats are protected by the Illinois Wildlife Code.  Like many other species, habitat destruction or disturbance is a problem for bats.  Pesticides used in the environment may be present in the insects eaten by the bats, and lead to poisoning.  Disturbances during torpor may awaken the bats, which wastes energy and fat stores, and can lead to starvation.

The increase in wind turbines across the landscape has led to an increase in bat mortality.  Some bats collide with the blades, while others, caught in the vacuum formed by the blades, experience a rapid change in pressure causing the lungs to expand and capillaries to burst. 

A recently discovered threat, White-nose Syndrome (WNS), appears as a fungus on the muzzle and wings of infected bats.  It is transmitted from bat to bat by direct contact, but it can survive on cave walls and floors and be carried from cave to cave by humans and other animals.  Over winter, affected bats awaken more frequently, wasting energy reserves leading to starvation.  More than 6 million bats have been killed by WNS in North America over the past six years.

With so many threats, bats need all the help we can give them, but remember NEVER touch a bat. 


Things you can do:


• Avoid entering caves where bats are roosting, especially between October and April.

• Be sure to clean any shoes, clothing, or equipment that you use in a cave before going into another    


• Limit your use of pesticides.

• Build a bat house.


Bat Conservation International ( has free plans for different styles of bat houses, but here is the basic Single-chamber Bat House:


BatHouse.jpgMaterials (makes one house)


• 2’ x 4’ piece of  1⁄2”-thick outdoor grade plywood

• One piece 1” x 2” (3⁄4” x 11⁄2” finished) x 8’ pine (furring strip)

• 20 to 30 exterior-grade screws, 1”

• One tube paintable latex caulk

• 1” x 4” x 28” board for roof

• Water-based stain




• Measure and cut plywood into three pieces: 261⁄2” x 24” 161⁄2” x 24,” and 5” x 24”

• Roughen inside of backboard and landing area by cutting horizontal grooves with sharp object or saw. Space grooves 1⁄4” to 1⁄2” apart, cutting 1⁄32” to 1⁄16” deep.

• Apply two coats of dark, water-based stain to interior surfaces. Do not use paint, as it will fill grooves.

• Cut furring strip into one 24” and two 201⁄2” pieces.

• Attach furring strips to back, caulking first. Start with 24” piece at top. Roost chamber spacing is 3⁄4”.

• Attach front to furring strips, top piece first (caulk first).

• Leave 1⁄2” vent space between top and bottom front pieces.

• Caulk all outside joints to further seal roost chamber.

• Attach a 1” x 4” x 28” board to the top as a roof .

• Apply three coats of stain to the exterior.

• Cover roof with shingles or galvanized metal (optional).

• Mount on building (south or east sides usually best).


Learn more about bats at

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