An analysis of western bluebird double and triple nest box research on Chehalem and Parrett Mountains in 1982. Nest usurpation and cavity use by Lewis' woodpeckers. The relationship between cavity-nesting birds and snags on clearcuts in western Oregon. Forest Ecology and Management. Shiflet, Thomas N., ed.
Rangeland cover types of the United States.
Society for Range Management. Birds of Maryland and the District of Columbia. Szaro, Robert Chester. Northern Arizona University. 264 p. Dissertation.