Research

North American Bat House Research Project (1993-2004)

A Decade of Bat House Discovery

America’s first known bat houses were built near San Antonio, Texas, in 1902. Hardly anyone noticed, and the idea of artificial bat roosts languished for the next eight decades. Then came the 1980s, and Bat Conservation International became the pivotal promoter of bat houses as an inexpensive way to help bats while cashing in on their voracious appetites for bothersome insects.

Bat houses began popping up in backyards, farmlands, and orchards around the U.S. and Canada, but their effectiveness was still hotly debated as recently as the early 1990s. Few systematic observations existed on the sizes, shapes, colors, building materials, or locations bats might prefer.

In the spring of 1993, BCI launched the North American Bat House Research Project, a long-term volunteer effort to quantify roosting preferences and fine-tune artificial roosts to better meet the needs of bats.

“The North American Bat House Research Project has revolutionized our ability to help bats in need of homes, thanks to the 7,000 Research Associate volunteers and colleagues who, over more than a decade, have shared their findings from varied climates and habitats across the continent. Today, at least 16 of 46 U.S. and Canadian bat species are using bat houses and other artificial roosts that shelter tens of thousands of bats, with 100,000 in just one extra-large structure.

Our efforts have mostly focused on species that prefer to roost in ¾-inch (19 millimeter) crevices, and, with the help of our Research Associates, we developed a basic bat house design that has proven acceptable for the majority of America’s most widespread species. Such houses, which do not require species-specific knowledge, enable countless novice bat fanciers, farmers and wildlife managers to install successful bat houses.

By sharing and analyzing the results of numerous tests involving crevice-dwelling species in wide-ranging habitats and climates, we have clearly documented key requirements. As research progressed, we periodically added new, more-refined reporting categories, which limits the number of years available for cross-comparison. We are, however, able to make consistent comparisons for 1,553 bat houses reported from 1998 to 2001.”

That excerpt is from Vol. 12, No. 1, Spring 2004, The Bat House Researcher, which was published twice in most years between 1994 and 2004. This was the final newsletter as the official project ended, and it summarizes the most important results from the experimentation across the U.S. and Canada. We have again posted every newsletter from this project so that you can read for yourself all about the experiments that individuals carried out on their own properties and the resulting knowledge that was gained. Though they are not recently written, the information they contain is still as relevant as it was from 1994 to 2004, and answers many common questions that are still asked by the public.

So, read, learn and enjoy--it is still a great idea to create more homes for bats—maybe more now than it ever has been!

Newsletter Archive

View the scanned copies of the The Bat House Researcher newsletter below. (Arranged by year and season)

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Pictured here is a bat house testing site.
Copyright Brian Keeley, Bat Conservation International