Conservationist Isabella Tree tells the story of a remarkable cuckoo called Sayaan, who in April this year returned to her home and rewilding project at Knepp for the third year running. They are part of the British Trust for Ornithology’s Cuckoo Tracking Project, putting GPS trackers on cuckoos so we can learn about their migrations and help conservation. Sayaan left his overwintering grounds in the Congo in January, and crossed Nigeria, Benin, Togo, Ghana and Côte d’Ivoire, refuelling on insects before heading off across the Sahara desert to Algeria, Ibiza and the Pyrenees. Finally he made the last 1000 km sprint to Knepp. For Isabella, the sound of every cuckoo, is the sound of triumph.

This programme features recordings by Hazel Reeves recorded at Knepp, and audio from Xeno-Canto by Frode Falkenberg (Common Cuckoo - XC1139781).

Produced by Sophie Anton for BBC Audio Production in Bristol.