Bats and Bridges

So what is it with bats and bridges?

Actually bridges are a prime habitat for bats these days. Once they lived in tree cavities or outside of Florida caves were always a prime roosting spot. But habitat destruction has greatly reduced their trees. Today the prime location to see bats is under a bridge. Small crevasses in the bridge joints can hold hundreds or even thousands of bats.

Brazilian Free-tailed bat

One of the many retirement hobbies I'm pursuing these days is bats. I'm currently volunteering with a group that's trying to map all of the bridges in Florida to tell which ones have bats and which don't.

I've included a couple of pictures of what to check for when looking for bats. First is the odor. A colony of bats puts out a lot of guano in a given day. It has a sour, musky odor. Unmistakable after you've smelled it. Bat guano is dry and dark, very different from a bird. Here's a video of the droppings of the Brazilian Free-tailed bat under a bridge (Just the thing to get everybody into their Friday).

Bat Droppings

Another thing to look for are dead bats. I saw several today.

Brazilian Free-tailed bat, RIP

I don't think the dead bats I saw today was cause for concern. It was just that it was a huge colony. On any given day a few are going to drop dead.

Another way to find the bats is to just listen. Brazilian Free-tailed make an audible chirping noise that you can hear if you stay quiet and they're nearby.

But a better question is why bats? Bats are important predators of about any insect in the air. They're also really cool animals that almost never actually turn into vampires. Yeah, they're creepy and smelly and everybody has heard a story about one that flew into somebody's hair. But they're really harmless.

So, I'll be posting a few updates when I can't think of any other subject for the day look at area bridges for bats. The last statewide survey of bridges was done in 2003 so we'll be looking to update that survey.