As I rounded the corner, I saw at least four gang-gangs call and land in a tree across the track. They then flew across the track to this old tree and a tree close by. Two females inspected hollows, a male stayed on a branch. After a few minutes, one pair flew towards the area where the Cam/Tom/Isaac hollows are; another pair flew up the hill towards the road, so I'm wondering if there is something to look for up the track. This left one pair in the old tree. The female sat at the lower hollow, closing her eyes, guarding. The male flew to a higher hollow and growled and talked and growled. I was about to move on, and lowered my head to quickly write notes. When I looked up, the female had silently disappeared. I am assuming (to my surprise) she moved down into the hollow. I watched the male and the nest hollow for the next 20 minutes - the female did not emerge, and there was no sound of chewing of the hollow. The male called and flew off, alone. So, perhaps another potential active nest site to monitor?