Those awfully nice chaps at Caught by the River have updated their Nature Book Reader webzine. It contains nature book recommendations from loads of people who simply love nature books. There are some top recommendations in there.
The latest update includes my own recommendation of Kathleen Jamie's wonderful books Findings and Sightlines, which I re-read every September without fail. If you haven't read these books, you should. In fact, you should order them right now:
(You can thank me later.)