For many of us, isolation is disconcerting and challenging, but for wildlife sound recordist Chris Watson, it is something he actively seeks, so he can fully immerse himself in a place and capture its unique sounds in his recordings.

In the fourth of five illustrated essays, Chris recalls his quest to record wild voices in the darkness and isolation of Dryburn Moor in Northumberland. It can be a real challenge to find a truly isolated place in the UK, but here on the high Pennines, Chris was rewarded with a serenade of birds, which he can hear but can’t see until the night evolves into day.

Produced by Sarah Blunt for BBC Audio in Bristol.