Here are several ways of building and installing your own bat house. We recommend downloading this "how to" PDF, though the options below are also approved.
Putting up bat houses is a great way to help bat populations that have plummetted in recent years. To increase the chance of enticing bats to take up residence in your bat house(s), consider the following:
- Temperature is a critical factor in roost selection. In Canada, bat houses should receive at least ten hours of direct sun each day, and more is better.
- Mount bat houses on poles or on the side of a building at least 12 feet (4 metres) above the ground (the higher the better). Houses mounted on trees are more difficult for bats to find and more vulnerable to predators.
- Bats need to drink water every night, so houses located less than a quarter mile (400 metres) from a water source, such as a stream, river, or lake, have the greatest success in attracting bats.
- Bats like a clear swoop zone to get in and out of their roosts, so avoid placing the house in an area where there are a lot of obstacles, such as tree branches.
- Placing two or more houses in one location allows bats to better respond to changes in temperature by allowing them to move between the houses as needed.
- Do not mount houses close to bright lights.
- In Canada's cold climate, bat houses should be painted black or dark brown to increase the inside temperature. Use water-based paint or stain, not oil-based. Apply three coats.
- Be sure to use untreated wood for your bat house. Pressure treated wood may contain chemicals harmful to bats.
- The inside of bat houses must be roughened to allow bats to grip. Create horizontal (not vertical) scratches or grooves. Space cuts roughly ½ inch (13 mm) apart and 1/16 or 1/32 inch (1 or 1.5 mm) deep. An alternative is to attach plastic (not metal) screening flat on the wood surface to avoid injury to the bats.
- Be sure to caulk all seams, especially around the roof, to prevent drafts and keep temperatures stable.
- Use exterior grade or galvanized screws rather than nails.
- If after two years your bat house has failed to attract occupants, try moving it to a new location.
Much to the surprise of wildlife biologists, sheet-metal collars wrapped around trees not only protect nesting birds from predators but also create ideal roosts for bats. Corrugated metal, loosely fitted, allows bats that normally roost under bark to regulate their temperatures by crawling around a tree to the sunny or shady side. Unlike loose bark, these metal collars can by placed where needed and last for years. They should be at least a metre wide, secured along the seam with aluminum nails, and have enough space underneath (two or three centimetres wide) that bats can enter and move around