BARRED OWL PLAYBACK SURVEY PROTOCOL: WHAT CALLS ELICIT A RESPONSE?
Nicole A. Bogle; Humboldt State University; 1 Harpst St, Arcata, CA, 95521; (209) 505-2453; nab373@humboldt.edu;
West coast wildlife managers in the United States have had to formulate new survey protocol in response to recent barred owl expansion (Strix varia) which has negatively impacted two subspecies of the spotted owl, the federally listed Northern spotted owl (Strix occidentalis caurina), and the California spotted owl (Strix occidentalis occidentalis). Analyzing barred owl response to playback call types could yield better survey design in order to increase detection probability and/or survey efficiency. We analyzed a total of 639 barred owl call back survey responses from Green Diamond Resource Company's "property wide" Strix surveys between March 2013 and August 2017 conducted in northwest California. Barred owl response varied significantly based on call type used. Conspecific playback call types elicited proportionately more responses than spotted owl calls. The "8-note" conspecific call elicited significantly higher responses whereas the "cackle/duet" call elicited a lower than expected response. Seasonal (March-May, July August), and annual response changes to call back surveys were not observed. Future research comparing multiple survey designs may yield useful information on which barred owl call types to use during surveys.
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