Bat House Central
Thanks for your interest in Bat Houses! Habitat loss is the greatest threat to our Northwest bats. While we all continue to work on protecting native habitat and landscaping with native plants, bat houses are one thing we can do locally to provide roosting habitat.
The first thing to recognize is that bat houses are not bird houses. You might just take some scraps of wood and slap together a bird house, but bats have more specific needs. If we are to reverse the negative trend of loss of roosting habitat, we need to know specific information about the roosting needs of bats.
Luckily, we do know a lot about those needs, largely thanks to the efforts of Bat Conservation International (BCI) and their Bat House Research Project. BCI's Frequently Asked Questions page is a great resource for more general information than you will find below. Also visit BCI's Criteria for Successful Bat Houses information sheet for specific information. Check out our list of recommended Bat books.
Buying a Bat House
Order a Rocket Box bat house from Bats Northwest; this style has been popular with bats in the Puget Sound region. To purchase other styles of ready-made bat houses which are part of BCI's Certification Program, check out BCI's Catalog, or Bat Conservation and Management has a line of commercially made bat houses and kits.
Some other products sold as bat houses are not well designed to meet the roosting needs of bats. Review the first three points below to guide you in selecting a house.
Building a Bat House
To make your own bat house here are some plans: Rocket Box Plans.
Design and Placement of Bat Houses
For the Pacific Northwest, especially west of the Cascades in British Columbia, Washington and Oregon, bat houses should be painted with multiple coats of flat black exterior latex paint and placed where they will receive full sun – baking in the sun – that's what our bats need and seek. A nice warm place to raise their young and decrease their metabolic needs during roosting.
Here are some important points for success in Bat House design and placement:
- Build or buy a house which is at least 2 feet tall, 14 or more inches wide and has a roughened or screen-covered landing platform extending below the house of 3 to 6 inches.
- The house can be single chambered or multi-chambered, but chambers should be 3/4 to 1-inch wide - a variety is good to provide for the needs of different species. This is particularly true for our Eastern Washington, Eastern Oregon and British Columbia bat house builders. Please include at least 1 or more 1-inch chambers in these areas.
- The houses should be caulked during construction and preferably screwed together. The idea is to create a TIGHT microclimate inside the house capable of trapping the heat captured during the day and generated by the bats. We are serious about this – the house should be tight enough that you could turn it upside down and fill it with water – that tight. OK?
- Most of us want bat houses around our house so we can observe them. So the guidance about being within ½ mile of water or other features such as orchards, forests, etc. are nice, but I would still put a house up where I live. Even in the city on the side of my condo. Construct it and put it up as described here and then forget about it. If it takes a year or two to be colonized, then you've still contributed to our knowledge about bat distributions and preferences. Be patient. Keep records and have fun.
- Place the house in full sun, best on its own pole, secondarily on the southern side of a building in full sun. Did I mention FULL SUN? Not hidden under the eves of the building, not in the trees. Most bat houses which weren't occupied that I have seen in Washington State (where I live) were mounted on tree trunks, at eye level, in the shade, and/or the entrances were obstructed by tree branches. That is a recipe for disaster -- or at least disappointment. Don't go there.
- Keep the area around the entrance clear of obstructions for 15 feet - vertically and horizontally so the bats can get up to speed as they drop out of the house without crashing into obstructions. Their bones are made for flying; these are not the baby-rubber bumper-bats of Halloween. These are delicate little flying mammals that could benefit from our help. They are agile and adept flyers, but let's give them a chance.
- Please be patient after you put up your house - it can take some time for bats to find you. If a season passes and you haven't become a chosen bat host, recheck the guidelines above, and consider modifying the house to better conform. We hear about people taking a wash of bat guano and marking the house to make it more obvious to bats. Not enough data are available to argue either way on this practice, but you are welcome to try a variey of things and keep records.
- Consider participating in the Bat Conservation International's Bat House Researcher program, even if you haven't yet suceeded in attracting bats. Negative results are just as important, as they can help us refine what bats of different species may be looking for in different regions.
- Use the Contact BNW part of this website to keep us up to date on your activities and progress. Of course we would be thrilled if you JOINED Bats Northwest!
More Bat House Info
This info is the "Uncle George" bat house, designed by Greg Falxa (Cascadia Research), "Uncle George" Carlson, and Sanders Freed.