I got the chance to live in the woods of Washington state for a little while. It was a dream come true for me, and I spent as much time while there studying the flora and fauna as I could. One of my favorite observations were the silver haired bats. They used to fly across the porch, and I could stand in the dark as they hunted insects right next to my head. I went to take the recycling out one night and collided with one once. We were both startled, but politely apologized and went about our activities. On other nights I would stand out in the open under the moonlight and play guitar. I began to notice that the bats would tend to hunt in circles more consistently around where I was emitting guitar sound, especially acoustic bass guitar. I ran many experiments over the course of a year’s time and I don’t think they would flock to the sound, but would concentrate around it if they were already out and catching bugs.
I would move around and found that they would move to where I was and circle overhead. I theorized that they were perhaps using the sound waves emitted from my guitar as extra “light” to find their prey. I know that the sound waves are in a very different frequency than their sonar systems, but their sensitivity to sound likely incorporates any sound within their field of perception. It felt a little like I was emitting a soft general light that brightened the overall vicinity, while they still emitted their own headlamps for direct tracking. I worried that I was perhaps interfering with them so I kept my experiments brief, but the results were consistent. They were generally drawn closer to the externally emitted sound, despite having a fully open sky to continue hunting in.
I did not get recordings of any kind, so I made this artistic depiction of the experience. I hope to try again some time. Bats are important creatures as both insect regulators as well as pollinators. Bats are responsible for some very specific plant pollination, yet still get a bad reputation from media and ignorance. They face some serious dangers of their own like white nose fungus, and human habits of habitat destruction. Do some research if you are averse to bats. They are adorable, helpful, and fascinating creatures.