These tiny frogs have an enormous voice for their size, and the recent warm evenings have been filled with their lovely chorus.

Most male frogs want their mating call to stand out from the crowd, and they do that by calling when nobody else is. This makes sure that the females hear them loud and clear, and know where they are.

The American green tree frog is a staple of summer nights in the U.S. South, where its groaning call echoes through countless swamps, forests, fields, and backyards. Yet even for many people who share ...