The northern spotted owl is one of the most studied birds in the world. Monitoring spotted owl populations throughout the species’ range in Washington, Oregon, and California is an extensive effort conducted among several agencies and partners. These efforts are not designed to count the number of individual spotted owls but rather to gather sampling data from which population trends are derived.
More specific spotted owl surveys also are conducted in areas where forest management activities may affect spotted owl nesting, roosting, or foraging habitat so that potential adverse effects can be avoided or minimized. The U.S. Fish and Wildlife Service develops survey protocols to ensure that spotted owl information is gathered in a consistent and scientifically rigorous manner. Survey protocols have been used since 1992 and were recently updated to take into account the effects the encroaching barred owl appeared to be having on spotted owl detection.
Survey Protocol
2012 Revision of 2011 Survey Protocol
Guidelines
Safety Guidelines for Conducting Spotted Owl Surveys
Call Station Placement (Pearson et al. 2010)
Factors Influencing Detectability (Kissling et al. 2010)
Reduced Calling in Rainy Conditions (Langane and Slater 2002)
Audio
Spotted Owl Audio Files (use “right click” on file and "open link in tab" to download all audio files)
Spotted Owl Audio File for Surveys
Audio Files from 1994 TWS-OR Northern Spotted Owl Vocalizations Cassette (use “right click” on file and save as target or link for all audio files)
Individual calls (13 files - zipped) (MP3)
Individual calls (13 files - zipped) (WAV)
Complete side A of tape (contains tutorial accompanying the 13 individual calls) (MP3)
GIS
ARU Survey GIS Layers-March 2021 (use “right click” on file and "open link in tab" to download zipped files)
