So here you see he jumps around, but at some point he flicks his wings above his back, looks like he flips the top surface up, and sound comes out. Here, this is at quarter speed. The sound is going to be lower pitch because we’ve slowed it down, but you’re going to see that wing goes up and there’s a wall of sound that just hits you, this maaaaahhh, sound like a, a foghorn. This is recorded at 1000 frames a second, slowed down so we can see what’s going on, and what you see is the wings go up above the back and then you get this knocking over and over and over and over again. This is actually occurring at 107 cycles a second or 107 times for every second that passes. Now to put that in perspective, when you see a sparrow flit by you, it’s beating its wings at about 20 or 30 cycles a second. If you see a hummingbird flying around at your feeder, it’s beating its wings at anywhere from 50 to 75 cycles a second. A rattlesnake rattles its tail at 90 cycles a second. 107 cycles a second is unbelievably fast for a vertebrate to be moving part of its body. So he’s moving his wings really fast, and he’s knocking feathers together above his back, or he’s knocking something on his wings above his back.