An update from the owner:
During the period of 3/21 thru 3/30, we frequently had both owls visible at the same time [“brown” owl in slot box & “white face” in round hole]. Since 3/30″brown” owl has been seen frequently in the slot box at various times during the day, but I haven’ t seen “white face” at all.
This afternoon, nearly every blue jay, robin, titmouse, etc in our neighborhood came into our yard making a LOUD demonstration! This hasn’t happened very often and the surprising thing is that the bluejays were “attacking” the round hole box, not the slot box where the “brown” owl had been roosting this afternoon.
Hmmmmmm, maybe “white face” hasn’t left the scene and maybe the round hole box isn’t vacant?
It will be interesting if they are nesting, to see which is the female, and which style she picked to be the nest box!