Nightingales sing during the day too! This was recorded at about 6 o'clock last May at Greenham Common near Newbury, Berkshire, England. It was cleaned up using Audacity. About 10 seconds into the recording you will hear a stretch of un filtered sound which includes buffeting wind and traffic. The noise filtering in Audacity is really good. This is my first attempt at podcasting - unsophisticated I know but that doesn't detract from the glory of the nightingale's song?
Every year I try to hear these birds and usually succeed. One summer night I heard the nightingales and saw glow worms!! A double wonder!