Claudio Mello was conducting research in Brazil’s Atlantic Forest about 20 years ago when he heard a curious sound. It was high-pitched and reedy, like a pin scratching metal. A cricket? A tree frog?

Anna's hummingbirds can reach top diving speeds of around 60 mph, but their normal flight speed is around 25-30 mph. During flight, the little birds can reach nearly 10 g's of force. When diving, ...

I was recently creeping through a clearing of downed trees in a wooded Brooklyn park with my iPhone in hand. Birds were singing everywhere, but through the din, I was recording a peculiar song: It was ...