Looking for White Nose Syndrome

This weekend I visited a large bat hibernaculum to see if the bats in the cave have been affected by WNS. The cave is in the southeast and I didn't think the bats would be affected (WNS is currently only occurring in the northeast), but the Fish and Wildlife Service wanted a group of us to check. This particular cave is closed to all visitation during the winter to make sure the bats aren't disturbed, but experienced cave explorers can get a permit to visit this area in the spring and summer. The cave just opened for the season last week so we decided to visit the cave the first weekend we could (with a federal permit in hand, by the way. Visiting federally owned caves without a permit is a federal offense and you'll get in really big trouble if you do it. So don't.).

It was a beautiful day to be out in the woods; the temperature was perfect, wildflowers were blooming, and trees were just starting to get green. After the usual long and steep hike to the cave, we rigged the entrance drops, 60' and 97' and proceeded the rappel into the entrance.

The first room in the cave is a large, open canyon with a very steep scree slope at the bottom. A small canyon at the side of the room leads further into the cave. This particular cave is extremely large and complicated. It consists of an interlocking maze of rooms, canyons, pits, crawls, and other obstacles. In the winter, due to the geology of this section of the cave, cold air is trapped in this entire section making the temperatures drop to around 4-5 C (37 F), which is extremely unusual for caves in the southeast. Typically caves are around 13.3 C (56 F) all year round. That's the kinds of winter temperatures gray bats (Myotis grisescens) require. Around 1.5 million gray bats hibernate here. Back in the early 1980s, the Fish and Wildlife Service purchased this cave to protect this bat colony. Gray bats are extremely susceptible to disturbance; they will wake up at the slightest noise. If the bats wake up during hibernation, they will end up flying around, which means they will use up a portion of their precious fat reserves that must sustain them throughout the winter. Because such huge numbers of bats hibernate together, when one bat is disturbed, that means a few hundred thousand bats are all disturbed. If the bats come out of hibernation too many times during the winter, they will use up their fat reserves and starve to death before spring arrives and they can begin hunting insects.

Now, back to our weekend trip. We weren't sure if there would be many bats still in the cave. I had an opportunity to visit the cave in the middle of the winter several years ago with a group of bat biologists, and every nook and cranny of the cave was packed full of gray bats. We didn't expect that this time. The weather has been very warm, plenty of insects are out, and we thought the bats may have mostly moved on to their summer caves (which are always very warm caves instead of cold). As we started down the small canyon into the cave system, we snaked through the passage and in a few minutes encountered several small groupings of grays. They clung to the walls with tiny claws, their wings splayed in odd angles holding to the rock.

Almost immediately some of the bats started to wake up, look at us, and make hissing and squeaking noises. We crept through the passage, trying to be as quiet as possible while at the same time checking out the bats. They looked like they were a normal weight, didn't have any signs of white fungus on their noses, and looked normal to us. We continued creeping.

Throughout the day we visited many portions of the cave. Bats were not roosting in smaller passages and canyons but were in the large, high rooms. We guess there were still several hundred thousand bats in the cave, and all of the bats we were able to inspect looked healthy. Here are a few more bat pictures.


Not finding any signs of WNS was a big relief. However, we plan to still keep an eye on them later this fall when they start to return to their hibernaculum. Because bats migrate, who knows how this illness will affect bats as they move between caves throughout the year.