The westward expansion of Barred Owls (Strix varia; BO) has intensified competition and predation pressure on the threatened Northern Spotted Owl (Strix occidentalis caurina). Understanding BO activity patterns can inform management strategies. We analyzed movement data from 47 GPS-tagged BOs in northwestern California collected over 20 months in 2023–2025. Accelerometer sensors recorded continuous activity and often triggered a false mortality event (“stillness”) after six or more hours of inactivity. We modeled stillness frequency using mixed models and examined association with sex, land cover, and weather predictors. Stillness did not differ by sex but decreased with elevation gain. Among univariate generalized additive models including temperature, precipitation, and day of year (DOY), DOY best explained variation in stillness (AIC weight = 0.998), with lowest stillness (i.e. higher activity) occurring midyear. Temperature and precipitation were not strong predictors once seasonal timing was accounted for. These results demonstrate strong seasonal patterns in BO activity, suggesting decreased movement during the non-breeding season. Identifying temporal windows of reduced activity can help refine survey timing and management actions to mitigate BO impacts on Northern Spotted Owls.