Spring in Sugarloaf Ridge State Park, in Northern California, is typically a natural symphony. Streams whoosh, swollen with winter rains, and birds — robins, sparrows, grosbeaks, woodpeckers and hawks — trill and chatter.
But in 2011, a yearslong drought set in. By spring 2015, a local creek had dried up and the valley had gone quiet. “The park went from an extremely vibrant habitat to one that was dead silent,” said Bernie Krause, a soundscape ecologist who has been recording in the park since 1993. “Nothing was singing, nothing was chirping, nothing was moving. It’s like it was dead.”