Sometimes it sounds like one of those big step-down transformers in electricity substations when it's raining. Sometimes it sounds like a piece of card being held against a fan through the slots in the back of a PC. Sometimes it sounds like the back wheel of a bicycle when you coast downhill without using the pedals.
This morning I saw what was doing it. Or, at least, one of the things that was doing it. It looked a little like a cricket and a little like a beetle, but it was about the size and weight of a four-month-old fieldmouse. It was beautiful.
As I type this, a voice from behind me is saying that this isn't quite what people are looking for when they're reading my journal. They weren't the exact words she used, but I think you know what she meant. More news later, I promise. It's looking good at the moment.