The Dawn Chorus is a phenomenon where many species of birds start their morning singing at the first light of dawn. Maybe it’s for the defense of breeding territories, or an attempt to find a mate; no one truly knows why.
Roosters and mockingbirds are probably the most familiar of the morning singers, but go outside in the early hours and listen closely – you’ll hear a variety of species greeting the day simultaneously. (In some places you don’t need to listen closely – the chorus in Stratford-upon- Avon, England was loud enough to wake me.) It begins tentatively with one or two birds, but soon is in full throat.
There is also an electromagnetic phenomenon which occurs at dawn and is caused by the same energy that drives the auroras borealis and australis. Related to birdsong? Unknown. What is known is that the earth wakes up singing.