Take a look at the new pictures posted over in the image galleries...tell me if you have any ideas what kind of bird(s) were investigating the nestbox today. My guess is a pair of hairy woodpeckers, based on the black and white pattern (and the fact that they live in SoCal), but it could be anything, really. Except they were likely NOT kestrels. But at least things are getting interesting around here! And we've not seen the RTHs back on top of the box since we removed the perch, so that problem may have been solved (knock on wood). They're still around, but only because the whole area around us is their territory.
Anyway, check the images and let's hear what you think it may have been! And way to go, Pat, for seeing it and grabbing the image!