WHAT ARE MY CHANCES OF ATTRACTING BATS?
How will bats find my bat house? How
long does it take? Can I “bait” my bat house with something to speed up the process?
These are just some of the most frequently asked questions about bat houses. This page
will help answer the basics about attracting bats and about being a responsible bat house
landlord. For more information, please consult the The Bat House Builder's Handbook, available at Bat Conservation
International’s online catalog: www.batcatalog.com.
The odds of attracting bats are very good for well-designed, well-built bat houses mounted according to recommendations developed by the Bat House Project during 12 years of bat house research by BCI and its volunteer
Research Associates across the U.S., Canada and the Caribbean. Here are a few of our latest results:
•Bats inhabited an average of 60 percent of all reported bat houses (both good and bad houses and installations) in BCI's 1999 to 2001 annual surveys.
•Occupancy in rural areas was 61 percent, compared to 50 percent for urban and suburban areas.
•90 percent of occupied bat houses were used within two years (with 50 percent occupancy in the first year). The rest needed three to five years for bats to move in.
•Tall designs like the multi-chamber (nursery) and rocket-style houses performed best in our surveys. For example, 80 percent of 123 houses with chambers at least 25 inches tall were occupied in 2000.
ATT R AC T I N G B ATS –
Bats have to find new roosts on their own. Existing evidence strongly suggests that lures or
attractants (including bat guano) will NOT attract bats to a bat house. Bats investigate new roosting opportunities while foraging at night, and they are expert at detecting crevices, cracks, nooks and crannies that offer shelter from the elements and predators. Bat houses installed on buildings or poles are easier for bats to locate, have greater occupancy rates and are occupied two and a half times faster than those mounted on trees.
Unlike domestic animals, bats are wild and free-ranging. It is usually illegal to buy or sell them, and permits to capture and possess bats are generally limited to researchers, zoos, wildlife rehabilitators and educational organizations. Catching and relocating bats to new areas is, in any case, highly unlikely to succeed. Bats have strong homing
instincts, and once released into a bat house, will attempt to return to their former home area. Consequently, placing bats in a bat house is usually futile and is not recommended. If a bat house remains unoccupied after two full years, consider repositioning of modifying the house.
TE M PE R AT U R E S –
Maintaining proper roost temperatures is probably the
single most important factor for a successful bat house. Interior temperatures should be warm and as stable as possible (ideally 80º F to 100º F in
summer) for mother bats to raise their young. Some species, such as the big brown bat, prefer temperatures below 95º F, while others, such as the little brown bat, tolerate temperatures in excess of 100º F. Bachelor bats are less picky and may use houses with cooler temperatures. The sides of wooden or masonry structure are the best mounting sites, especially in colder climates, because temperatures are more stable than for houses attached to poles. Bat house temperatures are influenced directly by the exterior color, compass orientation (east-, southeast-, or south-facing are generally good bets for single houses in most climates), the amount of sun exposure, how well the house is caulked and vented, and the mounting and construction materials. You may have to experiment to get the right placement and temperature range. You can always use a thermometer taped to a pole to see if temperatures are suitable inside the bat house (check the chambers high and low, and front and back).
Taken from http://www.batcon.org/pdfs/bathouses/attractingbats.pdf