When I returned past Baldy's site a couple of hours after sighting 4513363, I again found a pair of birds at Baldy's original hollow. The male was at the entrance again, and the female was perched higher up and around the other side. He didn't go in, but moved up towards the female before flying off to Baldy's hollow 3 (the one closest to the original) where she joined him soon after. He (possibly they) growled into the hollow for a while and then flew to hollow 2, where they both looked in but didn't enter. They flew off together soon after.