While in Baja recently, I not only discovered a great little bookstore in La Paz, but also a new field guide. It's a 2013 publication and it's better than any field guide I've seen. Thumb tabs, speed index, weather-resistant cover, perfect size, etc. Everything about it bears a closer look.
Check it out.

http://shop.nationalgeographic.com/ngs/product/birding-books/national-geographic-field-guide-to-the-birds-of-western-north-America

Joe Meche
Bellingham