Concern for potential effects on California spotted owls can constrain forest restoration projects intended to reduce large, severe wildfires and drought-related tree mortality in the Sierra Nevada. Thus, call-based spotted owl surveys are typically conducted as part of the planning stage of forest restoration projects with a goal of achieving a 0.95 probability of detecting owls at occupied territories. Call-based surveys, however, require extensive and potentially hazardous nighttime work, typically across two years. As part of the development of a one-year, acoustically-aided survey protocol for spotted owls, we created a tool to help prioritize areas for differing survey strategies (full/twilight/acoustically aided/no surveys). The tool provides predictions of the probability of occupancy based on historical occupancy information and/or remotely-sensed estimates of tree height. Areas with shorter trees (primarily within a large, severe fire footprint) had a low probability of being occupied. In unburned landscapes, areas with more tall trees and more frequent historical occupancy were more likely to be occupied. Using these predictors, managers can more effectively identify areas not needing owl surveys, areas where one year of acoustically-aided surveys are appropriate, and areas where call-based surveys can be conducted without nighttime work, while maintaining a detection probability of 0.95.

Anu Kramer received her PhD in 2016 from the University of California – Berkeley in Environmental Science, Policy, and Management, where she specialized in fire ecology, GIS, and remote sensing. She has been a Researcher with the Peery Lab at the University of Wisconsin – Madison since 2018, where she works primarily with California spotted owls, applying her knowledge of fire, GIS, and remote sensing.