Most of us associate bats with the night sky—flashes of shadow darting between trees, nearly silent. But bats are far from silent. In fact, they are constantly making sounds as they fly, hunt, and navigate. We just can’t hear them.
That’s because bats use a remarkable adaptation called echolocation. They emit high-frequency sounds, many of which are well above the range of human hearing. These ultrasonic calls bounce off objects in the environment and return as echoes, allowing the bat to “see” the world through sound. With echolocation, bats can detect tiny insects in total darkness, avoid obstacles mid-flight, and even communicate with each other. To our ears, bat calls are inaudible. But with the help of special equipment, scientists can record and slow them down—bringing the hidden soundscape of bats into our range of hearing.
Recently, we had the privilege of hosting Doris Audet, a world expert on bats, here at Cloudbridge. During her time at the reserve, she recorded some of the ultrasound calls made by our local bats. A few weeks later, Doris sent us an exciting update: she had analyzed one of the recordings and identified the calls as belonging to the Brazilian free-tailed bat (Tadarida brasiliensis).
Even more exciting, the audio includes a “feeding buzz”—a rapid burst of calls that bats produce after detecting a prey item. The buzz indicates the bat is closing in, adjusting its call rate to hone in on the target with incredible precision. It’s a rare and fascinating behavior to capture on audio.
Based on the frequency and structure of the calls and the big amount of them that she was able to record, Doris believes that Tadarida brasiliensis is not just passing through Cloudbridge—they are likely roosting nearby. This species is known for its fast, agile flight and is one of the most frequently recorded bats in the reserve’s acoustic recordings.
Thanks to Doris’s work, we now have a better understanding of one of our most elusive nocturnal residents. And thanks to her recordings, you can hear what a bat sounds like too—check out the video she shared with us, where the bat calls have been slowed down so that human ears can tune in.
Next time you walk under the stars at Cloudbridge, remember: the forest may seem quiet, but it’s alive with the chatter of bats, echoing all around.