I did some nest box checking and cleaning this past weekend, a few more to go, but got this note from the owner
On Saturday [9/17] That (the cleaning) must have made the box more attractive because there is a dark gray/brown owl in the slot box at 8:30 this morning! During the past month there have been a few raucus protests by the yard-birds, which have made me suspect the presence of an owl in our yard. It is gratifying to confirm an owl IS here, the first sighting since the owlets fledged last May.
The Circle hole box was completely cleaned out, and wood chips were replaced as this was the nest box. The slot box I did not replace any wood chips since this was not the nest box, just removed a few old pellets but left whatever feathers were in there. This is the first time that an owl has been seen so soon after a clean out on one of the boxes on this ‘trail’, but I know of at least one other instance of owl activity very soon after a clean out. http://celeryfarm.net/2008/02/owl-nest-box-ma.html#more there may be some to it being more attractive, or maybe a ‘who’s been sleeping in my bed’ in an owl way.
Update: seen 9-20 and 9-21
the owl was visible in the slot box for most of the morning & early afternoon, I had to peer through the dirt of both glass & screen doors and the walnut leaves so I didn’t have a clear view of it. With binoculars I could see that it had a dark gray-brown head with a lot of white on the breast.This owl did not look like any of the individuals documented in the many photos I took last season.
Some can’t get any owls, if this is a different owl, that would make 5 distinct individuals documented at this site in the last 1.5 years.