National Audubon Society Field Guide To Birds Western Region
A wonderful guide for a more experienced birder, not really something for good field use though, flipping back and fourth would get bothersome especially in a rough place. Much better to leave at home and refer to at leisure. The pictures in it are gorgeous though, of all the bird books I have I must say the images here are the best. Information is good, a good hand sized book. You could I suppose take it with you on a trip if you don't mind taking a moment to sit down and file through it. Not something I would recommend to an amateur birder though, it would simply be too hard to use in the field, an excellent back yard birding book for all levels though.