I can second TheSeagull's recommendation of "The Snow Goose" by Paul Gallico. It's a gentle novel. Nothing earth shattering but an easy read and full of a love for wildlife/birds.
I read The Peregrin by J.A. Baker. It's a desolate read which makes much more sense if you've read the preface by Robert Macfarlane. It's essentially about one man and his observations of Peregrins. I'm not sure it's one you can say you 'enjoyed' but it certainly conveys something of the cold, harsh reality of survival in the wild.