We recorded detections of other species of forest owls while surveying for the Spotted Owl (Strix occidentalis) in the central Sierra Nevada from 1 April to mid-August, 1997–2002. During 4,562 Spotted Owl surveys, we recorded 355 responses from six other owl species: the Northern Saw-whet (Aegolius acadicus), Northern Pygmy (Glaucidium gnoma), Flammulated (Otus flammeolus), Great Horned (Bubo virginianus), Long-eared (Asio otus), and Western Screech (Otus kennicottii). We did not detect the Great Gray (Strix nebulosa) or Barred (Strix varia).
After correcting for annual variation in survey effort, we estimated that detection rates for most species varied annually in a similar pattern. Most owl responses were recorded during April and May. These incidental detections are useful for documenting the presence of owl species in the central Sierra Nevada and suggest potential directions for future research.