One of the largest populations of Townsend’s big-eared bats in Colorado – and perhaps in the Western United States – has been discovered in the Crystal River Valley of northwestern Colorado, the Aspen Times reports.
Townsend’s big-eared bats, listed by the federal government as a “species of viability concern” because its habitat is being lost, are roosting in the abandoned Maree Love Mine on the lower slopes of Mount Sopris. The mine taps into a natural cave, Wildlife Biologist Phil Nyland of the Aspen Ranger District told the newspaper.
He said the exact number of bats using the mine is not available, but studies are under way to survey them and determine how often they use the mine. The mine apparently was a gold mine in the 1880s. Horizontal passages in the mine reach into a hot-vapor cave.
Aspen Times reporter Scott Condon wrote that the mine was rediscovered recently by a former coal miner who was exploring for minerals. The Forest Service controls surface rights in the area, the newspaper said. All mining and preparatory work has been halted pending the bat-habitat study, and the miner, Robert Congdon, is helping with the survey, says Aspen District Ranger Bill Westbrook.
Westbrook told the paper that it is important for an assessment to be completed before the Forest Service decides what level of use is appropriate for the Maree Love.
Nyland said research he suspects the mine’s large rooms and geothermal heat attracted the bats.
Townsend’s big-eared bats are found throughout western North America, from British Columbia south to Oaxaca, Mexico. Two endangered subspecies exist in isolated areas in the Ozark and Central Appalachian regions of the United States.
The bats’ typical habitat is arid Western desert scrub and pine forest regions. These agile fliers venture out to forage only after dark, using their echolocation abilities to hunt moths and other insects. In the spring and summer, females form maternity colonies in mines, caves, or buildings, while males roost individually.
In winter, Townsend’s big-eared bats hibernate in caves and abandoned mines. They are extremely sensitive to disturbance at their roosting sites and have suffered severe population declines throughout much of the U.S.