Written and illustrated by David Allen Sibley. Alfred A. Knopf, Inc., 2016. This guide is an indispensable resource for all birders seeking an authoritative and portable guide to the birds of Western North America. Compact and comprehensive, this guide features hundreds of bird species and thousands of illustrations. Each entry contains new text concerning frequency, nesting, behavior, food and feeding, voice description, and key identification features. Features 703 bird species plus regional populations found west of the Rocky Mountains with more than 4,600 accurate illustrations and descriptive text pointing out the most important field marks. 504 Pages. Flexibound cover. Used as is.