Bats have been showing up to our backyard around 9 at night. Krissy filmed them with her iPhone and played the clip back to me, pointing out that there was an intermittent static and clicking noise that could be heard. As a control, I made a video on my iPhone and a GH4. The same thing happened on my phone, but did not occur on the GH4. In both clips, there is an occasional higher pitched bat squeak. I don’t have an answer for what exactly is occurring with the static sound, but my guess is that it is the result of bat sonar and Apple’s electronics. While you might have to turn up your volume a little to hear it1, the sound is audible even on laptop speakers.
In the clips I have raised the levels 10db. ↩