The Sibley Guide to Birds has quickly become the new standard of excellence in bird identification guides, covering more than 810 North American birds in amazing detail. Now comes a new portable guide from David Sibley that every birder will want to carry into the field. Compact and comprehensive, this new guide features 703 bird species plus regional populations found west of the Rocky Mountains. Accounts include stunningly accurate illustrations—more than 4,600 in total—with descriptive caption text pointing out the most important field marks. Each entry contains new text concerning frequency, nesting, behavior, food and feeding, voice description, and key identification features. Accounts also include brand-new maps created from information contributed by 110 regional experts across the continent.