The Great Gray Owl (Strix nebulosa) is a California Endangered Species, with an estimated population size of only 100-200 pairs in the state. It is the largest owl in North America and one of the largest owls in the world. It is also one of the most reclusive bird species, which provides challenges in studying its life history.

Great Gray Owls have a Holarctic distribution, inhabiting boreal forests from Scandinavia across Russia to northern Mongolia and China, and across Alaska and Canada down to the Rocky Mountains, Pacific Northwest, and the Sierra Nevada.

Most of the California population is found in the greater Yosemite area, although breeding records extend on the western slope of the Sierra Nevada from El Dorado County to the boundary of Fresno and Tulare Counties. North of Yosemite, there have been scattered records in El Dorado, Nevada, Sierra, Yuba, Butte, Plumas, and Modoc counties with a few historic records in the Klamath Mountains in northwestern California. In California, Great Gray Owls most commonly nest in dense forest stands adjacent to montane meadows, where they hunt for rodents, although IBP has recently documented nesting areas that are considered atypical for this species (see the two peer-reviewed publications below).

IBP is engaged in multiple research and conservation efforts to benefit Great Gray Owls in California, including a collaboration with the California Department of Fish and Wildlife to develop a comprehensive Conservation Strategy for the Great Gray Owl in California (see sidebar). We also have an active research program, facilitated by partnerships with multiple government agencies and private land owners, that aims to better understand the species’ distribution and abundance in the state, habitat needs for nesting and foraging, and response to wildfire.

For more information about IBP’s work to study and conserve Great Gray Owls in California, please contact Helen Loffland.