While walking around my usual Green’s Bush circuit I noticed many Crimson Rosellas exploring every tree hollow on the older growth Eucalypts. A few went right inside the various cavities after a cursory glance, and several flew off quickly when an occupant was discovered (most likely a brush tailed possum or sugar glider). I found a pair really giving this hollow a thorough inspection. One did all the inspecting while the other stood guard on a nearby branch – he spent the time watching me on the trail and shaking his tail feathers now and again and quietly squawking. I assumed the other took this as a signal to be alert but not alarmed.