As pandemic lockdowns went into effect in March 2020 and millions of Americans began working from home rather than commuting to offices, heavy traffic in America’s most congested urban centers—like Boston—suddenly ceased to exist. Soon afterwards, the air was noticeably cleaner. But that wasn’t the only effect. A team of Boston University biologists who study how human-related sounds impact natural environments seized the opportunity to learn how the reduced movement of people would impact local ecosystems.