South Okanagan-Similkameen Community Bat Project
The main guidelines to use to install your bat-house are:
Mounting: Where to mount your bat house depends on the model. Single-chambered bat houses should be mounted on buildings (sides of barns, sheds, houses, etc). Wood or stone buildings with proper solar exposure are excellent choices, and locations under the eaves often have been successful. Multi-chambered (nursery) bat houses can be mounted in those locations, as well as on poles. Mounting two multi-chambered bat houses back to back on a pole is ideal since poles can be put out in the open, and bat houses can face due south. Place houses ¾ inch apart and cover both with a galvanized metal roof to protect the center roosting space from rain. Houses mounted on trees or metal siding are seldom used. All bat houses should be mounted at least 4 m above ground; 5 to 6 m is preferred. Bat houses should not be lit by bright lights.
Sun Exposure: The best aspect to mount your house in the Okanagan-Similkameen area is south or south-east facing. Bat-houses should receive at least 10 hours of sun and more is better. Full, all-day sun is often the most successful.
Obstacles: Bats like a clear path to fly out of their house so that they can detect predators and easily avoid obstacles. Bat-houses should be placed in open areas where there is no or little clutter such as on a post in the middle of a field, or on the side of a building with no obstructions for at least 5 - 7 m. If a bat-house is mounted on a tree, the branches should be de-limbed below and around the bat-house to create an open, uncluttered area.
Habitat: Most nursery colonies of bats choose roosts within 400 m of water, preferably a stream, river or lake. 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. Bat houses are most likely to succeed in regions where bats are already attempting to live in buildings. If a bat-house is being installed in combination with exclusion, you may wish to try several bat-houses in different locations including one near the current roost site. However, placing a bat-house where bats are exiting and entering the building is not always the best strategy. It is more important for the bat-house to be in a high, uncluttered and hot location than it is to be near the current roost site.
Wood Treatment: For the exterior, apply three coats of exterior grade, water-based paint or stain. Use a medium tone colours (e.g. lighter browns or greys) Try to select a non-toxic stain.
Protection from Predators: Houses mounted on sides of buildings or on metal poles provide the best protection from predators. Metal predator guards may be helpful, especially on wooden poles. Bat houses may be found more quickly if located along forest or water edges where bats tend to fly; however, they should be placed at least 6 to 7 m from the nearest tree branches, wires or other potential patches for aerial predators.
Avoiding Uninvited Guests: Wasps can be a problem before bats fully occupy a house. Use of ¾ inch (2 cm) roosting spaces reduces wasp use. If nests accumulate, they should be removed in late winter or early spring before either wasps or bats return. Open-bottom houses greatly reduce problems with birds, mice, squirrels or parasites, and guano doesn’t accumulate inside.
Timing: Bat houses can be installed at any time of the year, but are more likely to be used during their first summer if installed before the bats return in spring. When using bat houses in conjunction with excluding a colony from a building, install the bat houses at least two to six weeks before the actual eviction if possible.
Importance of Local Experimentation: It is best to test for local needs before putting up more than three to six houses, especially comparing those of different darkness and sun exposure.
Let us know! Part of the South Okanagan-Similkameen Community Bat Project is to determine what the best model and placement of bat houses are locally. Please register your bat house and let us know your success at www.bcbats.ca.
For more information on the South Okanagan-Similkameen Community Bat Project, see www.bcbats.ca