One of the best ways to support bats is to hang a bat house in your backyard. They give bats safe places to stay during the day while allowing them to move freely. Kevin O’Connor meets with general contractor Tom Silva and landscape contractor Jenn Nawada to talk about how beneficial bats are, and then Tom shows Kevin how to build a bat house to encourage these flying friends to nest.
The Benefits of Bats
Most folks get a little weirded out about bats. After all, they’re nighttime creatures and we’ve been conditioned to associate them with ghouls and goblins. But bats are extremely beneficial, and here’s why.
1. They’re Natural Pest Control
Bats are the best natural exterminator a backyard could ever ask for. These animals come out at night and snack on flying bugs like mosquitos to keep their populations in check. They also feed on harmful moths and beetles that attack crops, making them a farmer’s best friend.
2. They Pollinate
Bats use echolocation (their own form of radar) and their sense of smell to locate night-blooming flowers. They feed on the nectar, moving from flower to flower, promoting cross-pollination. They especially love fruit trees.
3. Agave Plants Can’t Survive Without Them
Agave plants—the plants used to create the natural sweetener and tequila—need bats for pollination. These plants have long, tube-like flowers that only bloom at night. Bats find them and use their long tongues to reach the nectar deep inside to promote pollination. Also, these plants only flower once before dying, which makes the seed production resulting from cross-pollination that much more vital.
How You Can Support Bats
One of the best ways to support bats is to hang a bat house in your backyard. These houses give bats safe places to stay during the day while allowing them to move freely around. At night, they can swoop out of the bottom and get back to their beneficial work.
How to Build a Bat House
Your plans will have the specific measurements, angles, and cut list required for your bat house. This is a helpful overview of the process.
- Cut the side pieces from the 2×4 with a miter saw. Our drawing called for 20-degree angles at the ends of the 2x4s and then a 21-inch length. Cut the angled ends first, square them together, measure 21 inches, and then cut the sides square.
- Cut the plywood sheets to rough size. You’ll need to cut the front, back, and interior partitions from the same piece of plywood. Remember that the interior partitions are about an inch shorter than the front to allow bats to move from front to back. Also, cut the roof pieces according to the plans.
- Add a “bat ladder” to the back piece of the bat house by cutting shallow kerfs from side to use. Use a table saw or track saw.
- Dry fit the bat house. Place the back down first, then the two side pieces. Next, lay a piece of scrap plywood down between the side pieces and then lay the first interior partition on top. Then add scraps again before adding the next partition. Finally, add the front partition.
- With a pencil, mark the locations for fasteners. It’s best to pre-drill for fasteners to prevent splitting or creating sharp edges inside the bat house.
- Apply caulk to the front and back of the side pieces before fastening them to the front and back panels. Fasten the interior partitions in place using screws. Use caulk on the roof pieces before securing them with screws.
- Drill ventilation holes in the sides of the bat house to promote airflow. ½-inch drill bits will do the trick.
- Apply water-based exterior-grade paint to the exterior of the bat house to protect it from the elements for as long as possible.
- Hang the bat house as high as possible in the yard so it’s protected from predators but also allow bats to swoop down as they leave the house.
Resources
For the building materials, Tom has chosen 3/4” exterior grade CDX plywood and 2×4 cedar board.
Tom uses a miter saw to cut the cedar board. He then uses a track saw to make all the other measurement cuts on the CDX plywood. To give the bats a better area to grip, Tom uses the track saw to cut a few rows of grooves on the bottom of the back piece.
To assemble the bat house, Tom secures the pieces with caulking adhesive and exterior-grade pocket screws. He then uses a drill bit to create venting holes, allowing better airflow. For the finishing touch, Kevin and Tom painted the bat house with exterior-grade water-based black paint.
Materials
- Bat house plans
- Cedar or untreated 2×4
- Non-treated CDX plywood
- Caulk
- Exterior grade pocket screws
- Water-based paint
Note: It’s important to use wood that has not been treated with chemicals. CDX plywood can be difficult to find untreated, so consider using another rougher plywood if you’re unable to find it. BC plywood will typically do the trick.
