Though still small, the field is growing, thanks in no small measure to Pijanowski’s tireless efforts (and those of his grad students). For the last several years he’s been circling the globe, depositing microphones in Costa Rica, Borneo, Tippecanoe, the Sonoran desert, Alabama, the wildfire-ravaged Chiricahuas, and urban parks in Chicago, often giving talks along the way. You get the sense he’s slightly reserved except when talking about sound, at which point he gestures expansively and uses words like "marvelous," "magnificent," and "glorious."

"There are what I call rhythms of nature."

Earlier this year, Pijanowski launched the Global Soundscapes Project, which is building a map of the world's sounds using an app that turns phones into recorders. Occasionally he has an IMAX crew in tow, part of a soundscape education program he’s filming. And every few months he convenes soundscape researchers for workshops, part of a grant from the National Science Foundation. He invites people from outside the sciences to participate. "When you look at arrangements of sound, working with musicians helps you to think about the orchestration of an ecosystem," he explains.

The idea that animal sounds follow a complex order goes back to Bernie Krause, a musician who in the 1960s and ’70s made a living doing sound work for the film industry, frequently taping things like jungle noises and whale songs. He became enamored of nature sounds and started accompanying researchers into the field to make recordings, eventually becoming the preeminent wildlife acoustician. In 1985, he was called on to lure a confused humpback whale, Humphrey, out of the Sacramento river using a feeding song.