Forest Bats

Bill Doering is a bat ecologist with two decades of research to his credit. He is studying bat migration across eastern Idaho’s desert. He spends weekends from August until Halloween in dark caves with rattlesnakes while trying to net bats. He keeps his rabies shot current, his headlamp close by, and, yes, he knows his idea of fun sounds crazy. This interview was conducted by Producer Kris Millgate in the summer of 2010.

Kris Millgate: If you’re after forest bats, why do you spend the night in a pitch-black cave in the middle of the desert?

Bill Doering sets up his nets in preparation for netting bats so he can quickly collect data on them and then release them.

Bill Doering: I’m trying to find forest species of bats that are crossing the desert and trying to find resources in habitats they don’t typically use. We really don’t know what forest bats do when they migrate. We know where they spend their summers, and they kind of just disappear and come back. We know they move south and toward the coast, but we don’t know how they do it. When they cross this vast sagebrush sea, they have to find places that hold the resources they need. Desert caves might be those places.

K: How well do you tolerate the temperature changes in the desert in the middle of the night?

B: I love it out here. I love this desert. When I started this project two years ago, I hadn’t been out in this country for a number of years, and as I drove off on the really bad roads, I just felt like the weight of real life was peeling off of me. It’s really neat country, and we’re fortunate to have it, but it does go from a hot day to freezing cold at night. There are broad temperature swings. Sometimes there’s a stiff wind, but not a lot of wind. Late in the summer you get that fall transition where it is really hot or really, really cold. It can change fast.

K: This isn’t an empty cave, and that’s concerning. There are hundreds of rattlesnakes in here too. How do you do your job without freaking out?

B: We’ve got wood rats and rattlesnakes. All of god's creepy creatures. Just behind us are 300 to 400 rattlesnakes that den here for the winter. One night, I was going to roll into a cave that I was convinced was too cold for rattlesnakes. I stuck my head in the hole and there was a rattlesnake looking back at me. Luckily, the Great Basin Rattlesnake is really mellow, but I was very close to the rattlesnake, and it was looking back at me.

I’ve had experiences where it’s pretty intense throughout the night. Truthfully, I don’t like walking around in the dark with rattlesnakes all around me. That’s why I bring my wife along. She studied snakes for her graduate work, and she’s got a good way with them.

K: Besides snakes, a lot of people are also uncomfortable around bats. How do you overcome the historical anxiety surrounding bats?

B: They’re not scary when you get to know them! They’re interesting. There are more than 1,000 species of bats. They have a very interesting physiology. They’re heterothermic, which means they can vary their body temperature. That’s something we can’t do. A bat can set its body temperature to be the same as its environment or be warmer and that’s control that we don’t have.

They are the only mammals that can fly and they can navigate well in the dark. They do echolocation and they’re comfortable in darkness. That’s where the problem starts with people. Bats are very confident fliers. They fly in the dark and generally humans don’t like the dark. The dark is full of all the things from our nightmares, so people generally don’t like things that move around at night and are nocturnal.

Bill Doering stands in the dark with an ultrasonic bat detector in his hand.

K: The full moon enhances the spookiness of your research. It also sheds a little natural light on what you’re doing in the dark. Is that a good thing or a bad thing?

B: A full moon is not very helpful for catching bats because as good as their ears are, they also have good low light vision and they can see the nets. Sometimes we don’t catch anything.

Usually I try to place the nets and take advantage of shadows behind a tree and guess where it’s going to pop out, but out here we don’t have that. You get skunked a lot of nights. They’re wily critters and they can avoid the nets.

K: I’m guessing the nights you get skunked are considered bad nights. What is considered a good night?

B: A good night is netting 30 bats, and it’s all done in a matter of minutes. I don’t want to stress the animals out. I want to collect data and release them quickly so I affect the animals as little as possible.

I have a favorite moment too. My favorite moment was clicking through my bat calls and seeing a hoary bat call. To see that hoary bat call on the computer screen was really pretty exciting. I use ultrasonic bat detectors and recording systems that hold thousands of calls. I’m collecting brand new data out here and downloading it on my computer. Somewhere in all the calls could be a brand new discovery.

K: White-nose syndrome, a mysterious and fatal disease for bats recently surfaced on the East Coast and is making its way West, quickly closing several caves to tourists who may be spreading the problem from cave to cave on their clothes. Do you look for signs of white-nose syndrome in the bats you net?

B: Sick bats have white, fuzzy mildew on their nose. That’s where the white-nose name comes from. I do look for that, but I haven’t seen it here yet.

It may be that some caves out here are too cold and too dry. Most of the caves back East have 100% humidity and the walls are drippy so it’s a good place to breed fungus.

White-nose syndrome disrupts a bat's hibernation cycle. Every time they are disrupted, they have a severe immune response. They are uncomfortable. Their water use goes up. Their metabolism goes up and they burn through winter reserves. The problem is so serious that some of the most common bat species may be in jeopardy of extinction, believe it or not, in just a few short years.

K: What’s the point of all of your risky research done in the dark with bats among snakes?

B: The information I’m finding I’m providing to agencies, and it’s information they need. These migrating tree species are the species that are at risk from wind development. It appears that the bats are attracted to wind turbines and we don’t really understand how, when, and where they’re moving around. Any information we can get on how, when and where they move around is going to help with site location, mitigation, and engineering solutions for these bat species at risk.