The publication of Field Guide to Birds of Western North America and its companion edition, Field Guide to Birds of Eastern North America, quickly established David Sibley as the author and illustrator of the most comprehensive guides to these regions. This second edition builds on this foundation of excellence, with a wealth of improvements and updates. It offers expanded and updated information, new illustrations, larger reproduction and an improved design. Covering species west of the Rocky Mountains, the book features illustrations of 777 species and regional populations, with more than 5,000 illustrations digitally remastered from original art for perfect reproduction, and more than 650 colour maps. This is an indispensable resource for all birders seeking an authoritative yet portable guide to the birds of western North America.