Texas Living

Why Every Backyard Needs a Bat Box

By Peter Simek 9.27.19

Bats get a bad rap. In films, they indicate horror settings or dangerous places. Vampires turn into bats. The superhero Batman is a moody loner, dark and mysterious. But in truth, bats are remarkable little creatures.

Unlike Batman, bats tend to be very social and live in large colonies. They’re smart and resourceful, have cool superpowers like echolocation to navigate in dark caves and at night, and if you’ve ever seen a picture of a little furry baby bat up close, you know that, reputation aside, bats are downright adorable.

Bats also play an important role in the ecosystem. Some feed on nectar and are pollinators. Some eat fruits and disperse seeds. Their droppings can be used as fertilizer. Most significantly, bats eat night-flying insects and bugs that can be a threat to agriculture. In fact, they are believed to be vital in helping to control the spread of insect-borne diseases including malaria.

Bracken Cave in Comal County is home to one of the largest bat colonies in the world, and that clan of sometimes 20 million bats eats corn earworms and cotton bollworm moths, helping to save Texas millions of dollars in damage to crops each year.

Bats are such a useful, adorable nature friend to have around, you might be wishing that some bats could move into your yard. The good news is, they can!

Here’s how to build a welcoming little bat box for your new nighttime friend.

What Is a Bat Box?

Whether or not you’ve ever seen a bat in your neighborhood, chances are — especially in Texas — they are already there. At least 33 species of bats share our state with us, and 11 are known to live near human populations.

They make their homes under tree bark and in tree cavities and hollowed-out trees, in abandoned mines, and in crevices under bridges. To coax them to your yard, all you need to do is provide a cozy habitat.

Bat boxes are simple wooden structures that imitate the kind of conditions bats find in the wild: narrow, tight spaces with rough-textured interior walls located in a spot that can stay warm, thus emulating the cozy space between the bark and the trunk of a tree and creating a place for your bats and their babies to curl up.

How to Build a Bat Box
Illustration by Kylie Valigura

Building a Wee House

Bat boxes are fun crafts you can easily knock out with the kids on a blustery October weekend.

For the exact design and specifications, go with the recommendations of the nonprofit Bat Conservation International (BCI). BCI recommends building a multi-chamber house, if possible. The most successful bat houses have roost chambers at least 20 inches tall and at least 14 inches wide, according to BCI, and taller and wider houses are even better.

Cedar or poplar lumber are recommended for your little construction; make sure you steer clear of pressure-treated wood that may contain chemicals toxic to the animals.

Here are the materials you will need for a four-chamber bat nursery:

2′ x 2′ plywood, ½”
2′ x 2′ plywood, 3/8″
1″ x 6″ x 8′ pine or cedar wood (3/4″ x 5 ½” when finished)
1 5⁄8″ coated deck or exterior-grade screws
1 1⁄4″ coated deck or exterior-grade screws
1″ exterior-grade screws
Dark, exterior-grade, water-based stain
Exterior-grade, water-based primer
Flat, exterior-grade, water-based paint or stain
One tube paintable latex caulk
Black asphalt shingles or galvanized metal
7⁄8″ roofing nails
Table saw or handsaw
Caulking gun
Power drill with screw bits
Paintbrushes
Tape measure or yardstick

To build your house, follow the cutting guide in BCI’s plans to cut the plywood into the shapes required to create the exterior walls and interior chambers in the house. The ½-inch plywood will be used for the shell’s front and back and the 3/8-inch plywood will be used to create the roosting partitions. The 1-inch board will be cut to create spacers that will help set roosting spaces. Don’t worry — the cuts are simple, and once you have all the pieces, they screw together simply. Then, seal with caulk and stain.

Not Too Hot, Not Too Cold

Bat boxes must provide a reliably warm environment. One way of regulating temperature is to paint the box. In warmer environments like Texas, dark or medium shades of brown and gray work well. In some parts of Texas, particularly the Rio Grande Valley and the western Hill Country, temperatures rise so high that bat boxes should be painted a medium or light shade of paint so they don’t become too hot.

Location, Location, Location

The location of your bat box will help regulate its temperature and provide other vital conditions that will help your bats thrive. Even though bats have a reputation for loving caves, bat boxes need lots of sun to stay warm. Bat boxes should also be located near a water source and should be at least 15 feet off the ground.

You might be tempted to mount your bat box on a tree — after all, that’s where bats like to live already. But the advantage of a freestanding bat box or one attached to a house is that it provides a cozy place for your bats away from the threat of predators that can climb trees. In fact, bat houses are best located at least 20 to 25 feet away from the nearest tree branches.

Enjoying Your Bat Friends

If the bats don’t move immediately into their new home, don’t panic. If the conditions are right, they will find it. Then, in the evening, you can pull out a lawn chair and watch as the amazing little guys flutter about, beginning their long night watch of keeping your yard free of pests.

© 2019 Texas Farm Bureau Insurance