Boulders and Bats and Bears, Oh My!

Winter is the perfect time to survey bats that hibernate in caves and mines across our region. Last week, Highlands Field Site Director Dr. Rada Petric, research assistant Adriana Kirk, and I visited several mines and caves that we are monitoring as part of a research project in collaboration with the US Forest Service and the NC Wildlife Resources Commission. We have deployed acoustic recorders to monitor daily activity in the mines. These devices record the ultrasonic calls of bats, and later, we use software to identify them based on their calls. However, as impressive as this technology is, it doesn’t reveal how many bats are inside each cave or mine. That’s why we visit each site once a year to tally the numbers.

This year, we counted several Tricolored Bats, one of the smallest bat species in the eastern US. Although once quite common, their populations have plummeted over the past decade due to a fungal disease called White-nose Syndrome (WNS). For example, in one natural cave we monitor in Swain County, biologists counted 1,600 Tricolored Bats in 2011; this year, Rada and her colleagues counted only 34. Because of these dramatic declines, the US Fish and Wildlife Service is considering listing the species as federally endangered.

Sometimes, you encounter more than just bats. We descended into a talus cave—a natural cave formed by a jumble of boulders—in Clay County that we had not visited before and discovered the skeletonized remains of an American Black Bear. We believe it was an older female, based on the size of the skull and the wear on its molars, and we suspect it was attacked and killed by a larger male bear, judging by the bite marks on the skull. Occasionally, male bears will attack, kill, and consume females and cubs; this one may have been targeted while it was denning. Fortunately, no large cannibalistic bears were inside the cave when we entered.

Jason Love
Associate Director, Highlands Biological Station