In the first of five Tweet of the Days this week, the BBC's security correspondent Frank Gardner recalls listening to great northern divers on television programme by Ludwig Koch, as a boy.

Tweet of the Day has captivated the Radio 4 audience with its daily 90 seconds of birdsong. But what of the listener to this avian chorus? In this new series of Tweet of the Day, we bring to the airwaves the conversational voices of those who listen to and are inspired by birds. Building on the previous series, a more informal approach to learning alongside a renewed emphasis on encounter with nature and reflection in our relationship with the natural world.

Producer: Tom Bonnett.