National Audubon Society Field Guide to the Rocky Mountain States

National Audubon Society Field Guide to the Southwestern States: Arizona, New Mexico, Nevada, Utah (Audubon Field Guide)

How to Do Ecology: A Concise Handbook - Second Edition

National Audubon Society Field Guide to the Pacific Northwest

Birds of Colorado Field Guide

National Audubon Society Field Guide to California

Scats and Tracks of the Rocky Mountains: A Field Guide to the Signs of 70 Wildlife Species (Scats and Tracks Series)

National Audubon Society Field Guide to North American Trees--W: Western Region (National Audubon Society Field Guides)

Colorado Nature Set: Field Guides to Wildlife, Birds, Trees & Wildflowers of Colorado

Rocky Mountain Nature Guide

National Audubon Society Field Guide to North American Wildflowers: Western Region