Philosopher and musician David Rothenberg has spent decades collecting and studying the calls of birds and whales. In the early 2000s, he began playing along with them, taking his clarinet and saxophone to some of the furthest corners of the planet. The result is a new form of music that invites us to question where art ends and science begins. We speak with David about his unorthodox project, Darwin’s theory of sexual selection, and what it’s like to accompany the sounds and songs of beings who may vanish from the earth.