|USGS photo in public domain|
Peepers are tiny frogs, no longer than your average paper clip and maybe as wide as a kid's thumb. They're tree frogs that, this time of year, migrate to ponds in search of a mate. And that's what all the singing is about - guy peepers seeking gal peepers.
A peeper song sounds just like a chick peep, with a rise at the end. To make that sound the guy - and it is the guys who sing - takes a deep breath, closes his mouth and nostrils, and then pushes air across the vocal cords. Put a bunch of guy peepers in a pond and get 'em singing and it sounds like jingle bells - and the sound can travel far, at least half a mile. If you don't have peepers in your neck of the woods, click here to listen.