Yesterday I was walking the greenway in south Charlotte with my sister and nephew, who are visiting from Wisconsin. We went out to an area with a lot of standing water looking for frogs and found a number of bullfrogs, as well as a few smaller green frogs. Since the frogs were all just kind of chilling at that point in the evening, my nephew (being a 7 year-old) moved on to other things. He ran up and down the boardwalk chasing and being chased by the small flies that were building up at dusk.
It was in one of those moments that I heard an odd sound in the distance. As we were looking around for bullfrogs, my first thought was that I heard a weird echo from one of them. But then, a minute later, I heard it again. A ‘hurumphing’ sort of sound. As my nephew got farther down the boardwalk and the rest of the world got quieter, I could make out the click and the low-pitched booming sound. It was an American Bittern. These heron relatives make some great sounds, most of which comes from large extensions of the esophagus. In some ways, they’re very much like the bullfrogs that surround them.
The actual vocalizing in these birds is fascinating to watch. Yesterday’s bird was tucked deep into the reeds and cat-tails, so I couldn’t see him, but I have watched them perform their booming calls before. The male goes through all sorts of contortions to pull air into the esophagus and then violently jerks his head and neck to keep making the booming sounds. It’s really amazing. As his neck swells up with air, white feathers may be seen, too.
At the end of a bout, it’s also fun to watch him deflate. All that air that has been built up to help those low frequency sounds resonate through the swamp slowly seeps out of his body. His body shrinks like a balloon with a slow leak in it.