Bat houses can help bats by providing shelter in areas that no longer
have their natural roost structures, such as large, dead, hollow trees.
Also, the bats in your area may choose to roost in a bat house rather
than in your attic! We will focus here on small-scale bat
houses for homeowners, local parks, or community gardens. But much more
is being done: parks such as Sun Lakes in Eastern Washington, for example,
have mounted very large houses that attract thousands of bats. Bridges
have been modified to provide bat habitat, and people have even created
artificial caves for bats. Visit the Bat
Conservation International website for details.
Our focus at Bats About Our Town is on basic bat house facts
and on helping you position a bat house effectively so that bats will
use it. For those who want to build a bat house, links are given for bat
Bat house facts for homeowners
- A bat house will not attract bats into your attic. If bats like
your attic, they will already be there.
- If you wish to exclude bats already living in your home, but want
to keep them nearby, you can create a bat house for them as an alternative
living space. See Bat
Encounters for information about bat exclusion.
- Bats will eat many, but not all, of the insects in your area. Predators
never kill all of their prey or there would be no food for the next
- Bats may also fly to popular feeding locations like Capitol Lake
rather than staying by your home all evening.
- It may take several years for bats to find and use a bat house.
bat houses are closed on the sides and top, and open at the bottom,
where the bats enter and exit. They contain partitions that are separated
by 3/4 inches width, and NO WIDER. Any wider than ¾ of inch will only
make it more attractive for wasps, but not bats.
- The best houses allow
bats to move to cooler or warmer sections as needed.
Getting a Bat House
- Bat houses for outdoor use come in two basic shapes: a flat, rectangular
box mounted on a building (NOT on a pole please), or a rocket-shaped
box on a tall pole. Each type can work well in the Pacific Northwest. The
building creates thermal mass that moderates temperature swings. The
double rocket box model does the same, and allows the bats to move
around according to the temperature they need.
- Indoors in an attic or barn, simply mounting boards the required
distance apart (3/4 inch) is enough.
- Bat houses may provide just one chamber for the bats, or multiple
chambers, depending on the number of boards used.
- The master site for
bat house information is the Bat
Conservation International website.
- Free plans for a rectangular single chamber bat house.
- Free plans for mounting a bat house on a pole or on a building.
- Creative examples of indoor bat habitat construction.
- For sale
at 1-800-538-2287 or on the site: The
Bat House Builder’s Handbook, a very thorough guide that
includes plans for multi-chambered rocket box and flat box bat
- Bat houses are also for sale at this site. If you buy
from another site, check that bat house against the BCI certification
information to make sure you get a good design.
Constructing your bat house
- Provide crevices that are ¾ inches wide and NO WIDER (wasps love
the wider spaces and bats don’t).
- Caulk the box so well you could carry water in it without dripping.
- In the Pacific Northwest, paint the EXTERIOR ONLY with a flat black
paint—three or more coats for lasting coverage. (Warmer or dryer regions
need other painting strategies—visit the Bat
Conservation International website for instructions.)
- Make the house so sturdy and well caulked that you won’t have to check
it every year.
- Mount it on a pole or a building, not on a tree. Bats don’t like boxes
on trees, which are vulnerable to predators and usually too shady.
- Position it away from lights in the night (streetlamps for example).
- Position it for maximum morning sun, east or south facing if possible.
it 15 or more feet in the air on a 4” x 4” pole or other strong support.
Put something on the pole to prevent predators from climbing to the
- On a building, position it so that predators such as cats and racoons
cannot reach it.
- Contact us with questions about positioning
Are bats using my bat house?
- Sometimes the bats are using a house as a night roost between feeding
bouts but not sleeping there during the day. If so, you won't see
them during the day. But you can check this by putting a piece of
white plastic on the ground under the house and seeing if it collects
Troubleshooting if bats are not using the bat house
- First, cross-check the list above about constructing your bat house.
Make sure you are following all the guidelines.
- Bats About Our Town
offers talks and consultations about effective
- Contact us to find out more.