Surveying Great Gray Owls throughout the Sierra Nevada

The Great Gray Owl (Strix nebulosa) is North America's largest owl in terms of body length (Great Horned Owls are more compact, but weigh more), and surely one of its most magnificent birds. In California, the species is primarily restricted to the Yosemite area, where it nests in late-seral forests adjacent to montane meadows or other forest openings. Nevertheless, records exist from far-flung corners of the state, including the Cascade/Siskiyou range, the Modoc Plateau, and the most southern reaches of the Sierra Nevada. The state population has been estimated to include fewer than 150 individuals, and the species has accordingly been designated an Endangered Species by the State of California and a Sensitive Species by Region 5 of the USDA Forest Service.

During the past five years we have conducted Great Gray Owl surveys in collaboration with the Forest Service throughout the Sierra Nevada, most recently on the Humboldt-Toiyabe National Forest. The focus of our efforts has been to survey areas for which there are historic or anecdotal detections of the species, but no firm data documenting present-day site occupancy or reproductive status. Although the species is notoriously difficult to survey, we have successfully documented occupancy at numerous sites, and collected data for inferring absence at many others.

Pinpointing the locations of breeding pairs enables federal land managers to do all they can to protect the habitat on which these rare birds depend.

 

2001 crew members Paul Burton and Henri Robert at a survey site on Sierra National Forest.

2002 crew members Bree Surges and Dan Sines.

2006 crew members Dayna Mauer and Lynn Schofield with their survey gear.

For more information, please contact Rodney Siegel.

HOME   BACK