The dawn chorus is most noticeable in spring when songbirds start to sing (to advertise for a mate or defend their territory) as daylight begins. So International Dawn Chorus Day is held annually on the first Sunday in May, and people are encouraged to rise early to listen to bird song either at an organised event or just in their backyard.
While those who live in an urban area might hear only a solitary blackbird or robin, they may be surprised at the number of other birds singing as dawn breaks — even the smallest gardens and pieces of overgrown wasteland can provide territory often unnoticed birds. Those lucky enough to live in more rural areas could be in for a real treat.
As usual there's more information and a register of organised events on the International Dawn Chorus Day at www.idcd.info. Or hunt out your local nature reserve or birdwatching group and see if they're organising anything.