Outside the range of our senses, the animals around us chirrup, shimmer and moanby Cal Flyn / June 8, 2019 / Leave a comment
A couple of weeks ago, I spent a magical, sundazzled evening as a moth whisperer. It was easy: I went down to the woods alone at golden hour, and drew from my bag a rubber bung about the size of a pencil eraser. I placed this mysterious object atop a broad, mossy stump. Then I waited.
This bung was, I’d been promised, a pheromone lure. Soaked in chemicals selected to mimic those of female emperor moths, the lure was supposed to attract the large, dramatic males from the undergrowth and into my net. A charming concept, but one I couldn’t quite bring myself to believe in. Anyone who’s spent time “spotting” wildlife knows that it rarely shows up when we’re looking for it.
I lay back in the grass, let dappled light dance across my face and waited. After 15 minutes I was feeling silly—glad I’d not brought an audience—and was about to pocket the lure and go home when the moths came racing out of the heather. First one, then two more, and then a fourth, each fluttering and frantic, limbs awhirr, with a dark eye on each wing and a pair of fabulously baroque combed antennae. I caught one, and soon it was walking across my hands quite fearlessly, wings shivering in the breeze. It felt like sorcery.
The pheromone signalling got me thinking about the invisible, inaudible messages that are being broadcast around us at all times. What stations are being played on channels that we simply can’t tune into? What signs are left hanging that we haven’t the capacity to read?
When I went moth-hunting a few months ago with the lepidopterist Reuben Singleton, he brought a sensor that allowed him to detect different species of bats as they flew overhead from their distinctive pattern of ultrasonic chirruping. A common pipistrelle, for example, echolocates by emitting sounds between 45,000Hz and 70,000Hz. Humans only hear from around 20Hz to 20,000Hz. (This reduces steadily through our lifetime; it’s easy to check your range online—at 32, my hearing kicks in somewhere around 60Hz and falls off by 15,000Hz.) By slowing recordings down, we hear the bats as a series of wet slaps and clicks, all extremely loud—around the same…