How to Make a Bat Roost Box

Bat roost boxes are increasingly popular among conservationists and homeowners alike. As development causes the destruction of bat habitats throughout the United States, declining bat populations are leaving a tremendous void in the food chains. Unfortunately for many individuals, bats are among the most prodigious consumers of insects in their habitats, including mosquitoes. The loss of these predators can mean vast increases in bug populations, effectively ruining your backyard barbecues. Installing a bat roost box in the yard can be a natural and noble way to control pesky insects, and it is a fairly easy construction project to undertake.

Things You'll Need

• Wood saw
• Drill
• 2-by-4-foot section of 1/2-inch-thick plywood
• 1-by-2-inch by 8-foot length of pine wood
• Screws
• Exterior-grade, water-based black stain and primer
• Caulk and caulking gun
• 4-by-24-inch piece of wire mesh

Instructions

1. Cut the plywood into three different pieces. The first, which will be the back of the bat roost box, will measure 26.5 inches by 24 inches. The second will measure 16.5 inches by 24 inches. The third will measure 5 inches by 24 inches.

2. Take the 26.5-by-24-inch plywood piece and use a knife or other sharp instrument to roughen one side. This will provide traction for the bats as they climb up into the roost later. The gouges should be spaced about 1/2 inch apart, and should be made horizontally.

3. Stain all of the plywood pieces. Use two coats to ensure a dark finish. Do not substitute paint for stain.

4. Take your pine strip and cut three pieces. One will be 24 inches long and the other two will be 20.25 inches long.

5. Attach the pine strips to the largest plywood piece. The 24-inch length of pine will be flush with the top edge of the 24-inch wide section of plywood. The 20.25-inch lengths will be placed on either side of the plywood piece, flush with the edges and perpendicular to the 24-inch length so that they make right angles at the top corners of the plywood. Caulk before placing the strips in place to create an airtight seal.

6. Attach the 16.5-by-24-inch section of plywood to the strips, which will serve to space the back and front sections of plywood so that the bats can nestle safely inside. The 16.5-by-24-inch plywood piece will match up with the top section of the larger plywood piece.

7. Space down 1/2 inch from the bottom of the 16.5-by-24-inch plywood piece and attach the 5-by-24-inch plywood piece. This will create a ventilation slot.

8. Place the wire mesh piece at the bottom of the bat box on the back plywood piece. This will help the bats land on the box safely. Caulk all joints so that the chamber is airtight. Stain the exterior as you did the interior, and contact your local extension office for advice on mounting the bat roost box for the species that live in your area.

References

• Maryland Department of Natural Resources: Bats