The poetry of birds

I don't think my poem below would qualify, but I do actually like poetry that features birds, which is usually about so much more than the birds. If I was going to indulge in a book, just because I thought it was a lovely book, a contender would be this one.

Questions on blogs are risky, but if you were going to splash out on a nice book, let's make it a hard cover book, preferably with pictures, which book would it be?