1) Effective conservation of the northern spotted owl (Strix occidentalis caurina) requires accurate occupancy and space use information, especially as passive acoustic monitoring becomes the primary population assessment method. Spotted owls actively vocalize in core use areas during the breeding season, but interpreting acoustic data is complicated by variable detectability—particularly for females—and interference from invasive barred owls (S. varia). 2) Using a dense network of autonomous recording units deployed 0–3 km from known activity centers, we quantified spotted owl vocal activity by sex and context. We additionally analyzed detection patterns from regional monitoring sites overlapping our study area to refine our understanding of detectability. 3) Male four-note calls were detected more frequently and consistently than female calls, and detection rates decreased with barred owl presence. Female calls were infrequent and restricted to the activity center and immediately adjacent areas, especially if nesting. 4) Vocal space use areas were similar in size but smaller than published home ranges, reinforcing that territorial calls represent high-use areas, not full spatial use. Synthesis and applications 5) We propose a detection-based spectrum of weeks with detection for inferring site occupancy that accounts for calling rate, caller sex, and project objectives. Stricter thresholds can minimize false positives in population assessments, while inclusive thresholds reduce false negatives in habitat protection. Our results support nuanced, objective-based thresholds for interpreting spotted owl detections from passive acoustic monitoring. This approach balances accuracy with conservation risk tolerance, demonstrating that suitable habitat extends beyond acoustically inferred territories. By clarifying vocal behavior, this study advances the application of passive acoustic monitoring for habitat management and occupancy estimation amid invasive species pressures and ongoing landscape change.