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What We Do/Caves & Mines


The Subterranean Program is currently deployed to North Mexico, helping our BLM partners with AML remediation efforts.

Planning for bat gating continues at various sites in southern and central Arizona. The public and bats protected all in one package!

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Conservation Issue

Abandoned mines throughout the United States provide homes for more than half of America’s bat species – some shelter as many as 1 million bats. Unfortunately, these old mines often pose threats to human safety. While these mines must be managed and the threats to public safety reduced, their loss would be a critical threat to America’s bats. And if mines are closed before being examined for use by bats, the bats can be entombed inside. BCI’s Subterranean Program works to preserve this unique subterranean habitat and to protect these bats.

Despite greater awareness, largely due to BCI’s pioneering Bats and Mines Program, some government and private managers lack the resources to effectively address bats in mines over large areas. Bats, meanwhile, are losing their natural habitat due to human disturbance and urbanization. Noise, light, and, air pollution all take their toll on bats, and transportation and energy infrastructure can pose additional hazards. 

However, bats have one man-made resource that they have come to rely on: Abandoned Mines. Our Subterranean Program allows us to shine a light on these often unknown habitats, and facilitate solutions that both protect the public from dangerous abandoned mines, and provide the best chance for bats to continue to use these crucial habitats.

Who We Are

BCI’s Subterranean Program has been providing advice, field support, gating recommendations, and project assistance to land managers throughout the world since 2008. In that time, we have surveyed over 4,000 abandoned mine and cave features, and helped protect and ensure continued access to habitat for hundreds of thousands of bats.

More Than Meets The Eye

Abandoned mines are both a unique resource and a unique hazard on the landscape. In some cases, their difficult-to-spot nature can make them ideal hideaways for large populations of roosting bats, such as migratory or maternity colonies. Mother bats about to give birth look for secluded, persistent roosts that will remain both undisturbed and accessible on the landscape year after year. But these hidden shafts and adits can pose serious, even lethal threats to humans by their nondescript nature, and at times natural appearance. Stay Out, and Stay Alive!


The BCI Subterranean Program works with land managers to ensure that crucial bat habitat is protected on the landscape, often via the implementation of bat gates in every form, ranging from culverts and grates to the large and well-known cupola gates. These solutions seek to protect the public, and the bats, for many years to come. If you have questions about how to implement a bat gate, or are curious about the answers that subterranean surveys may provide. Learn more about what we do.

Contact BCI Subterranean Program

Photos © BCI: Jason Corbett, Joseph Monfeli

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Last Updated: Tuesday, 10 September 2013
Unless otherwise noted, all images are copyright ©Merlin D. Tuttle and/or ©Bat Conservation International