A soundscape for Episode 4. A British woodland thick with birdsong; blackbirds, larks, dunnocks, wood pigeons. The rustle of leaves and the distant bleat of sheep. Headphones are best. With sound design by Graham Wild and Becky Ripley. Don’t forget to take part in our Forest 404 Experiment to see how you respond to natural sounds at: bbc.co.uk/forest #Forest404