IDAHO FALLS (AP) -- A dozen caves on federal land in Idaho will be closed this winter to give hibernating bats a decent sleep.
Two species of the winged mammals in Idaho are suffering alarming declines, said Paula Call, U.S. Bureau of Land Management outdoor recreation planner.The 12 caves shelter some of Idaho's largest remaining populations of Townsend's big-eared bats and Western small-footed bats. The colonies range from 50 to 1,000 animals each.
In some local caves, bat populations have dwindled to half of what they were 10 years ago when biologists first started counting them.
The bats perform a public service by keeping insects under control, Call said.
The closures affect only a small portion of caves in the area, and most people do not even know about them because the locations are kept secret, Call said.
If spelunkers have a specific destination in mind, the BLM will tell them if the cave is open.
People who wander into caves during the winter months inevitably disturb hibernating bats. Even someone creeping quietly through the lava tubes will rev up bats' lowered metabolism rates, Call said.
That causes the animals to burn precious body fat they need to last through the winter. Biologists think human disruption, combined with pesticide use, has contributed to bats' decline.
"Bats that are disturbed can very easily starve to death before insects are available in the spring," she said.
In the past, the BLM has had problems with people covering walls with spray paint and destroying rock formations, Call said.
The closures remain in effect from Oct. 15 to May 1. Signs will be posted to let the public know which caves are off-limits.