One of the most beautiful descriptions of birds in the wild that I have ever read is that of John Muir. For today's children - and adults- who don't realize how much nature has been lost, this book is an eye opener. It's true that we still have some birds around, but the sad story of 1,000 birds falling dead out of the sky in Arkansas is further evidence of their precious fragility. Muir's writings are clear and beautiful.
John Muir : Nature Writings: The Story of My Boyhood and Youth; My First Summer in the Sierra; The Mountains of California; Stickeen; Essays (Library of America)