Patrick told me, almost three years ago when I met him in the fall of my first year of graduate school, that the sound of cicadas was silence for him.
I heard my first cicada last summer, I think--or at least it was the first time I paid attention to the sound and remembered what Patrick had told me. It was somewhere in the midwest, and I called to ask if the screaming in the evening was his silence.
Tonight, we sat outside and ate dinner on the back porch, and a cicada started up partway through. Only male cicadas sing, and their song comes from moving membranes called tymbals back and forth in their abdomens, which are hollow to amplify the sound. It's a mating call, and there are actually some species of cicada whose song is loud enough to cause hearing loss in humans--this would, however, require the cicada to be sitting right next to someone's ear, which probably doesn't happen all too often, because if this were next to my ear, I'd make sure it wasn't there for very long.
Back in Seattle, Clementine had a water fountain instead of a dish, and it would burble away in the kitchen all the time. Once, I cooked dinner with Ari in Issaquah, and I kept leaving the faucet on partway, letting water trickle into the sink. I couldn't hear it; Ari had to keep turning it off for me. Water running in the kitchen was silence.
The cicada in the tree kept up for a good while tonight, vibrating his tymbals and screaming away, calling for a mate. I suppose it would become silence after a while, just like the fountain in Seattle. When the sun is going down, and the cicadas all come out, the sound--for me--isn't silence so much as it is open, big & wide & open in the Alabama night.