Counting bats in infrared: a follow up to Bat Crash in the Daily Mail #WNS

above, caving in Infrared

I received a lot of email over the weekend about the Bat Crash photos that appeared in the Daily Mail last week. In general there were two questions, 1 how did you actually make the photograph? and 2 aren't you hurting the bats by shining strobe lights on them?

Let me see if I can answer both the questions at once. When I was assigned to shoot the bat photos I knew I wanted to disturb the animals as little as possible. Photo Engineering at National Geographic (think of them as the photo version of James Bond's Q Branch) sent me a nikon camera and special strobes modified to record the near infrared spectrum that bats don't see. I also rented a special infrared camera that actually sees heat (that is what the photos above and below are from).

The scientist that I was working with assured me that the bats were going to wake up no matter what I did. People in the cave at all would rouse them, it didn't matter to the bats or the scientists if I used special non invasive technology or not so long as we worked quickly. The scientists were doing the count because the felt (rightly as it turns out) that the winter of 2010 was the last time that they might be able to get an accurate count of a healthy bat population.

The plan was to work west to east across the state visiting 4 caves in as many days. We'd start with the caves least likely to be infected with WNS and end with the caves most likely to be infected. For the first 2 days I tried my special equipment. Neither of the cameras produced publishable photographs. The modified Nikon was impossible to focus and frame in the dark and the heat camera's resolution was too low to publish. Look at the photo below, it is a composite of 15+ images and we still couldn't publish it because no one can tell what they are looking at (you are looking at the heat signatures of a few thousand bats on a cave wall).

The other part of the equation is the bats were rousing with or without me in the cave. So when it was time to photograph the big colony in Hubbard Cave I decide not to mess with the IR cameras and just used regular strobes.

I have a fantastic assistant named Alan Cressler. Alan and I have worked together for a long time and when I say "Alan can you move that light over a little" he knows exactly what I mean. Alan and I headed into the cave directly behind the scientists doing to bat count and as soon as they got their count underway we bagan making photographs. We both had Quantum q flashes controlled by radios. I put mine on a rock to the left of the camera and bounced it off the ceiling. That light would fill the shadows a little, Alan climbed the slope and shined his light on the main body of bats and people doing the count. In this photo you can see Alan on the right hand side of the frame providing light. We were in and out of the cave in under 30 minutes.

 In case anyone is planning on going into Hubbard, just know it is guarded by the largest cave gate ever built.

Stephen Alvarez

Sewanee, TN

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