Set in England in a vague time period, possibly post-war (I read it about 30 years ago), it's about a baby, raised by badgers and other forest creatures, who eventually, with a girl he 'rescues' from a normal, middle-class life, goes on a quest to save all wildlife.
It involves lots of walking across the country along ley-lines and lots of other environmental stuff that wouldn't be out of place now. Man=bad, wildlife=good sort of thing.
no time to do it for you right now, but you need to look at Abe Books website, it's a website with a search function for books. You put in all sorts of keywords from the plot, characters etc and it churns out all sorts of possible published books from that.