“We have a field station out in the desert,” he explains. “Deserts are phenomenally quiet environments, especially in the fall and winter. And so I went out there in September and put out a mouse in a small cage, with a microphone next to it. Then I put some dry leaves inside the cage with it. When you want to catch an owl, this is what you do so that the mouse walking around in the cage makes a sound that the owl can hear.”
