Project overview: Survey the distribution and abundance of California spotted owl populations in Yosemite to understand the long-term impacts of wildfire on species mortality and habitat use, and to guide long-term species management.

How your support helps: Recently listed as “threatened” in the Sierra Nevada under the Endangered Species Act, California spotted owl populations have declined some 50% in the past 20 years due to high-severity wildfire, tree mortality, drought, and intense storms.    

From 2015–2017, Yosemite Conservancy funded a landmark study to investigate the effects of the 2013 Rim Fire, the largest recorded fire in the Sierra Nevada at the time. In the ensuing decade, megafires have become a regular occurrence and have emerged as a primary driver of California spotted owl decline. Understanding how these fires affect owls’ occupancy, space use, and reproduction over time will facilitate better land management to help California spotted owls persist in burned landscapes.   

By resurveying the owl population over a decade after the Rim Fire, park scientists will be able to understand the long-term consequences and management implications of megafires and pervasive tree mortality.

This year: In 2026, this project will build on past findings from the 2015–2017 study to provide insights into the interactions among wildfire, drought, tree mortality, and California spotted owls. Already, park scientists have noted that initial results from the 2024 and 2025 field seasons indicate that some owls have shifted their territories since the 2015–2017 study, potentially in response to post-fire tree die-offs. These project insights are critical for managing owl habitat in California. In Yosemite, it will allow park managers to protect local nests and owls. On a larger scale, this project will support an understanding of the long-term effects of wildfire on this federally listed subspecies throughout the Sierra Nevada.

Project partners: Yosemite National Park; The Institute for Bird Populations

Photo credit: Jon Felis

Heather Mackey

Project Notes

"The California spotted owl (CSO) is proposed for federal listing under the ESA. High-severity fire, tree mortality, and climate change are the greatest threats to the Yosemite population."