We've known Sam Lee, a fine folk singer and collector of folk songs from Gypsy and Traveller communities, for a while as he used to teach folk singing classes that we attended.
He has become a bit of an expert in tracking down the last remaining strongholds of this now endangered British icon - and inviting small groups of people to venture into the night forests to hear them sing. In fact, I bought such an adventure for Dave as one of his birthday presents.
The book was as interesting as you'd imagine - with sections on the habits of the bird, its presence in the arts and folk song, and how you can get involved in living the kind of sustainable life that will help protect them and our other wild species.