Reddit reviews The Bird King: An Artist's Notebook

I'll second James Gurney's books, his blog and his "In the Wild" video series.

I really like the Complete Guide to Drawing Animals by Gottfried Bammes. It brought together a lot of concepts about anatomy in art that I hadn't really fully understood until I read it. Similarly, I think Sarah Simblet's Botany for the Artist has beautiful and inspiring art.

I'm a big old paleontology nerd, so I have a lot of books on my shelves with fantastic paleoart: Dinosaur Art, edited by Steve White, is a great showcase of modern paleoartists, and Feathered Dinosaurs is full of gorgeous paintings by Peter Schouten. For drawings of dinosaurs of the non-extinct variety, I'm fond of Katrina van Grouw's The Unfeathered Bird.

And I just got a copy of Shaun Tan's The Bird King and, oh man, I really love it. His imagination is incredible. Highly recommended for when you're in a creative rut.