Number observed: 1
Comments: Heard 1 trilled call from campsite, then went to look for the bird. Played a BOOW recording in the direction of the first call and got a response within 3 seconds, an abbreviated decending trill of fast hoots. Not the typical song but had the quality of a boreal owl. Heard 2 more calls after that, all shorter 3-4 note phrases with the same quality. Perhaps a young bird or non-breeding bird practice singing?