Iron Gate Construction Protects Endangered Bat Species

Vermont Cave Longest in New England and Home to 20,000 Bats

Dorset, VT—23 September 2004— The Nature Conservancy announced today the completion of a new bat gate at Dorset Bat Cave, Mt Aeolus, just in time for the peak bat swarm. With the assistance of volunteers, bat experts and staff, over 5,000 pounds of L-section iron was transported up a mile of steep, rocky trail to the entrance of the cave.

"Cave gate design must allow for natural air movement and bat flight, while controlling human access and resisting vandalism," said Rose Paul, Director of Science and Stewardship at The Nature Conservancy. "Much of the Dorset cave stays above freezing during the winter creating an ideal climate for hibernation, and it is one of only four hibernation sites in New England for the endangered Indiana bat."

As the Fall swarm reaches its peak in late September thousands of bats will emerge every evening to mate, teach their young how to find the hibernation sites and build up essential fat stores to survive the winter. Measuring 22ft wide by 13ft high the gate is designed with minimal use of vertical supports to allow the unimpeded flight of a large volume of bats.

The US Fish and Wildlife Service Private Stewardship Grant Program awarded a $16,625 grant to help finance bat gate construction and develop a cave management plan in conjunction with partners and experts. The Nature Conservancy is actively raising private funds to match the federal grant award.

The Dorset cave provides winter refuge to over 20,000 bats including the federally endangered Indiana, the state threatened Small Footed, the Little Brown, Big Brown, Northern Long-Eared and Eastern Pipistrelle. More than half of the 40 bat species found in the United States are in severe decline or listed as endangered. Colonies found at the edge of their range, such as the Indiana in Vermont, are vitally important for genetic diversity and the survival of the species.

"When I first got into caving, it never occurred to me that casual visitors to a cave could easily kill off bats," said Jansen Cardy, a caving enthusiast and volunteer for The Nature Conservancy. "With proper management, recreational cavers and other legitimate groups can still enter bat caves in the summer, but during the winter when bats are vulnerable human access is restricted."

Any human activity in or around caves can subtly alter the temperature and humidity and rouse the bats from hibernation, causing them to fly around and burn precious fat reserves. Pesticides and other pollutants are also taking their toll on the bat population. Pesticide residues are stored in fat tissue, and when released in concentrated amounts can result in chronic or acute poisoning leading to a change in metabolism or even death.

Bats often incite mixed reactions from the people they encounter, but they also provide important ecological services. Some 70 percent of all bat species eat insects, with even small bats capable of eating up to 1,200 mosquitoes and other insects each night. With West Nile Virus cases expected to exceed last year’s numbers, bats provide an underappreciated service to outdoor enthusiasts and reduce the need for farmers to use pesticide.

Protecting bat populations requires the conservation of both subterranean winter hibernation sites, and summer habitat in mature forests and river-side corridors. Many bat species, including the federally endangered Indiana bat, migrate to Vermont each summer and form maternity colonies in the forests of the Champlain Valley. Over the next five years The Nature Conservancy will plant 19,000 trees, grown from locally collected seeds, to begin restoration of summer foraging habitat for bats along the Poultney and Mettowee rivers.