Habitat relationships for Northern Spotted Owls in the Eastern Cascades region of Washington

The northern spotted owl (Strix occidentalis caurina) is a species of high conservation concern, and is listed as threatened under the Endangered Species Act of 1973.  In addition to problems stemming from habitat loss, spotted owls are facing increasing pressure from the invading barred owl (Strix varia).  Despite adoption of the Pacific Northwest Forest Plan, intended to ensure owl population persistence, the latest demographic studies provide little evidence of recovery.  An improved understanding of owl habitat relationships would provide a basis for more effective conservation and habitat management.  In this study, we characterize owl habitat associations and describe new habitat selection models for the eastern Cascade dry forests of Washington.  Topographic and habitat data were compiled at several scales around 262 owl activity centers and 195 random locations in the same geographic region and tested for predictive power.  Significant variables included precipitation, percentage of the buffer in riparian habitat, elevation, forest type, forest association class, crown cover, and tree size.  These variables were used to construct predictive habitat models that were successful at predicting owl habitat.  The resulting models can be used to help identify habitat for surveys and to guide management activities.