Blackcaps have a beautiful, melodic fluting song, a little like the sound of a babbling brook. In some ways parts of its song are a little like those of a blackbird, but higher pitched, with shorter individual notes which don’t slur together so much, and there are occasional more rasping notes too.
They may sing at any time of the day, but more usually in the morning, and often from within thick vegetation within a large hedgerow or close to woodland, usually at about head-height but sometimes high up in a tree.
It’s very difficult to tell the song apart from that of a garden warbler, but blackcap phrases are usually shorter [not always!] and are more likely to end on flute-like notes [though not always!]. If I get a chance I’ll record a garden warbler, but numbers have declined somewhat recently [they tend to migrate further and may have suffered from poor weather or feeding conditions in Africa] and there were none at Woods Mill, but perhaps this year we’ll fare better.