Birds sing the most about an hour before dawn, when the air is at its stillest. Theoretically, this enables sounds to travel farther, making song up to 20 times more effective than if sung at midday.

Each spring, birds across America are in full voice. Cardinals chatter, sparrows sing and warblers warble. Birdsong lifts the human spirit – “‘Hope’ is the thing with feathers,” after all. Yet birds ...

Not all birds sing, but those that do — some several thousand species — do it a lot. All over the world, as soon as light filters over the horizon, songbirds launch their serenades. They sing to ...