Observations of heat-stressed, sometimes dead bats associated with bat houses, have led to unfortunate speculation that bat houses can become ecological traps that lure bats to their death.
It is true that numerous bat houses are badly built and sold with unreasonable claims and little, if any, instruction on bat needs. Vendors of such houses defraud customers and threaten the credibility of bat conservation. Both vendors and customers can benefit from education and certification. Nevertheless, there is no evidence that poorly constructed bat houses threaten bat survival. Bats are smart enough to avoid bad bat houses except when desperate from lack of alternatives.
Bat houses are outstanding tools for education. When I introduced them to Americans in 1982, my primary objective was to help people overcome fear and accept bats as valuable neighbors. That goal has been vastly exceeded. Today, hundreds of thousands of American bats live in a wide variety of bat houses.
Individuals who have carefully tested local bat preferences, and adapted accordingly, are reporting close to 90 percent occupancy. Nevertheless, there is still much to be learned. And that is why we’re initiating new collaborations.
Late last month, local member, Debbie Zent, founder of Austin Batworks, reported an impressive event. Her three-chamber nursery house had been caulked, sealed, and painted inside and out, and was mounted high on a streamside ranch building—a nearly perfect combination. But to find it overflowing with occupants just days later was surprising.
Was this extraordinary success due to house or location quality, or were these bats simply desperate?
For the past 18 months Merlin has been assisting Harrison Broadhurst and Christopher Rannefors in creating a line of designer bat houses, attractive to both home owners and bats. Their curving architecture isn’t, just pleasing to the eye. At least theoretically, it may increase the area available for roosting, since most bats appear to prefer to line up with faces exposed to the outside air, not to another’s posterior, quite understandable!
The new houses are constructed of kiln-dried, sustainably sourced, three-quarter-inch western red cedar, with each piece dovetailed and caulked, thus minimizing leakage. Roosting chambers are extra tall (20-26 inches) and vented to ensure thermal gradients preferred by bats. All landing and roosting surfaces provide one-eighth-inch-deep cross cuts at half-inch intervals, ensuring maximum footholds for young bats. By avoiding plywood, the possibility of early deterioration and potential off-gassing are finally eliminated. Furthermore, treatment with Thompson’s WaterSeal Semi Transparent Stain & Sealer will additionally protect against warping. BatBnBs come with complete instructions and are easy to mount.
We’re proud to be a part of Harrison and Chris’ efforts on behalf of bats and a safer environment. They’ve been featured in dozens of leading publications and have even appeared on several television shows. You can learn more about them and obtain your own BatBnB by visiting their online shop. By using the code MERLIN when ordering you will be given a 10% discount, and the company will donate to MTBC an additional 5% of all orders using this code. Feel free to share this discount and BatBnB’s website with friends and let us know about your progress. By purchasing a BatBnB, you can reduce the threat of harmful pesticides in your neighborhood and help MTBC educate the world about these invaluable neighbors.