Next Sunday, 7th May, is "International Dawn Chorus Day" so where ever you are you can take part just Google IDCD and you will find an event near you.
This morning I was out in the wood (Glenborrowdale RSPB Reserve) by 4.30 am; the birds start up at least an hour before sunrise.
Then the migrant warblers usually start up, the chiffchaffs, wood and willow warblers. But this morning there were no warblers. Perhaps it's been the cold arctic winds in the last week that has slowed them down getting here.
The chorus has male birds proclaiming their territories and females selecting the fittest males, the strongest singers, for mating. You don't even need a wood just step outside at dawn with a coffee to enjoy a free natural concert. In urban areas the chorus tends to start earlier to avoid the background noise of traffic and aircraft. This is a good example of evolution in real time!