Building Homes for Bats
Build a bat box and learn about the little brown bat.
- Target Age: 5-8
- Learning Goals: construction and following plans, observation, planning
- Related Episode: Episode: 136: A Bat in the Brownies
In this activity, you and your child will build a bat box and learn about the habitat preferences and shelter needs of the little brown bat. After building bat house your child can use the criteria for good bat house placement to choose the best spot for their bat house(s).
This activity is particularly timely as bats need our help right now! They are experiencing large population declines due to a fungus. For more information about this fungus, visit Batcon.org.
Bats don’t always live in caves and abandoned mines. In colder regions, bats spend winter months in caves and abandoned mines to hibernate through the winter (these are called hibernaculums), but in the spring and summer bats spend their time in trees, under bridges, and in old buildings where they give birth and rear young. Bats love tight spaces to crowd in and use their combined body heat to keep warm. There are several factors that make a good summer home for a bat, and it starts with the building of the bat house!
There are several commercial bat house kits (also called bat box) available that contain pre-cut wood and only require assembly. These are certainly an option for a home project and can be found from many sources. As well, it is possible to make a bat house from scratch. Both options are outlined in this section.
Detailed instructions on building a bat house from scratch can be found at the end of this activity sheet.
Not all commercial bat house kits are the same. Often the less expensive kits are actually only decorative and at the very least would be unusable by bats. If choosing a commercially available bat house kit, be sure to purchase one that is certified by Bat Conservation International here.
Bat Conservation International also publishes The Bat House Builder’s Handbook, which includes the most recent bat-house research data and up to date bat box designs and tips for success. This book is available on their website here.
Note that for all options your child will need to be closely supervised as the use of hammers, nails, screwdrivers, and screws are necessary. For some options a saw may also be needed. It is recommended that an adult supervise each bat house being built.
Once you and your child have successfully built a bat house you will need to decide where to place it. The following criteria are important to keep in mind: (adapted from Bat Conservation International bat house criteria sheet)
- Sun exposure: Bat houses where high temperatures average 80° F (27º C) should received at least 10 hours of direct sunlight and more is better. At least six hours of direct sun is recommended for all bat houses where July’s daily highs are between 80° F and 100º F (27º C and 38º C). To create favorable conditions for maternity colonies in the summer, internal bat-house temperatures should stay between 80° F and 100º F as long as possible.
- The greatest bat house success has been achieved in areas of diverse habitat, especially where there is a mixture of varied agricultural use and natural vegetation. Placement should be within ¼ mile of water (preferably a stream, river, or lake).
- Bat houses should be mounted on buildings or poles. Houses mounted on trees or metal siding are less used. Wood, brick or stone buildings with proper solar exposure are excellent choices, and houses mounted under eaves are often successful. Mounting two bat houses back to back on poles is one option that is ideal. Houses should be placed ¾ inch apart and cover both with a galvanized metal roof to protect the centre roosting space from rain. Bat houses should be mounted at least 12 hours above ground, and 15 to 20 feet is better. The house should not be in a location where it is lit by bright lights.
- Houses mounted on the sides of buildings or on metal poles provide the best protection from predators. Bats may find houses more quickly if they are located along forest or water edges where bats tend to fly. However they should be placed far from tree branches or other perches where aerial predators can land.
- Open-bottom houses greatly reduce problems with birds, mice, squirrels or parasites entering the house, and guano (bat excrement) does not accumulate inside. If wasps nests accumulate, they should be removed in late winter or early spring.
- Bat houses can be installed any time of the year.
Take It Further
A Bat’s Favorite Food
There are over 1100 species of bats in the world and they eat all sorts of different food! About 367 species eat fruit, 11 species are considered carnivorous and more than 722 species eat insects!
Have your child make 3 posters with pictures of each food group (fruits to represent the diet of fruit eating bats, cows, horses and sheep to represent the diet of the carnivorous bats, and mosquitoes and moths to represent the insect eaters). You and your child can use online sources and books (example: Bats of the World by Gary L. Graham, or Walker’s Bats of the World, by Ronald M. Nowak) to try to find as many bat species as you can that eat each type of food.
More Ways to Discover and Learn
Go on an Adventure!
Organize a bat outing! There are many options available for visiting a bat viewing site. Bat Conservation International publishes a map of bat viewing locations around the world that can be found here. In addition, your local zoo or university biology department may have information on where to safely view bats locally.
When organizing such an outing it’s important to always have an expert guide in attendance who has experience with the location and to follow all safety guidelines as published locally. This is important for both the safety of you and your child, but also for the safety of the bat colony you are viewing.
Bring a notebook and pencil to write down observations during the visit. For example, to record the number of bats, if there were multiple species, if there were any mothers and pups and if they saw any bats catching and eating insects.
Have your child choose their favorite bat species from the ones you saw on the outing (or from the posters they made of the different diets of bats) and create a guide book entry for them including:
- A picture
- The common name and scientific name
- Information about:
- range: what part of the world it lives in
- habitat: what habitat it lives in (forest, caves, near water)
- diet: what is the bat species favorite food
- special feature: does the bat have any special features?
Once they have completed their entry, place them in a binder encourage your child to add entries to the bat “guide book” as they learn about new and interesting kinds of bats!
Hibernaculum: A mine or cave where bats who live in colder climates spend the winter hibernating together in large groups.
Look in a Book
Use these books to help children learn about little brown bats which are among the most common in North America:
- Shadows Of Night: The Hidden World of the Little Brown Bat by Barbara Bash. Gibbs Smith, 2004.
- Beatrice La Bat by Harla H. Robertson. Tate Publishing, 2011.
- Boo, the Little Brown Bat by Paula Pifer. Purpose Life Publishing, 2006.