National Audubon Society Field Guide to North American Birds, Western Region
Virtually every bird found in western North America is brought to life in this portable guide, an essential companion in the field and a staple in any birdwatcher's library. It features a durable vinyl binding and brilliant full-color photographic identification pictures arranged for quick access and definitive text, including information on the bird's voice, nesting habits, habitat, range, and interesting behaviors. Accompanying range maps; overhead flight silhouettes; sections on bird-watching, accidental species, and endangered birds make the National Audubon Society's Field Guide to North American Birds the most comprehensive available.
Note: the Eastern Edition generally covers states east of the Rocky Mountains, while the Western Edition covers the Rocky Mountain range and all the states to the west of it.