Colorado Birds : A Reference to Their Distribution and Habitat by Robert Andrews

Colorado Birds by Andrews & Righter

Birds of Colorado Field Guide - Paperback By Tekiela, Stan - GOOD

Crucible for Conservation by Robert W. Righter

Colorado Birds Distribution & Habitat; Andrews And Righter Denver Museum

The Guide to Colorado Birds - Paperback By Gray, Mary Taylor - VERY GOOD

The Battle over Hetch Hetchy: America's - Paperback, by Righter Robert W. - Good

Mountain Wild Flowers of Colorado by Rhoda N Roberts, et al - Vintage Paperback