Recently as I was approaching a pond while walking in DC’s National Arboretum, I was startled by a prominent, lone “boing” emanating from the bushes. It sounded almost mechanical, and at first I thought there was some device that was triggered by approaching hikers — to what purpose I couldn’t imagine. As I passed the pond, I heard the sound again and stopped. After a few moments, the boings started coming in more frequent succession, almost like an orchestra very slowly warming up. In fact, the more I listened, the more it sounded like viola strings being plucked, followed by a short glissando. Curious, I struggled to see the source of the developing symphony. Finally, there they were, periodically hopping in pursuit of one another on the muddy banks of the little pond: frogs.
I’m not certain of the species, but the green heads, size and spotting suggest that they were bullfrogs, and the sounds were their mating calls. I’ve heard frogs croaking before, but never a sound like this:
To produce the distinctive sound, the frogs would expand sacs beneath their jaws, like quickly inflating a balloon. Then two frogs would hop toward each other, touch their mouths together in a froggy kiss and do a little dance. Invariably, at least while I was watching, the suitors were unsuccessful — apparently the females were not suitably impressed by the dance. But the “singing” did get their attention.