ANG ELLIOTT DIDN’T REALIZe the birdsong he was missing until the Worm-eating Warbler incident. In the 1970s, a professor noted the bird, but even standing beneath it, Elliott couldn’t pick out its lusty, high trills. “I’m watching it throw its head back and open its beak and sing its heart out. And I still don’t hear that bird,” he recalls. This “ear-opener” led to an experiment: Elliott slowed the speed—and lowered the pitch—of
