Walking down the trail I heard the call of a Gang-gang Cockatoo then I heard a noise like wood being struck once. I quickly found the tree where a female Gang-gang was chewing bark outside a hollow. When the female investigated the hollow she did not go all the way into the hollow, only up to her wings. It looked like she was obstructed from going any further in. She then took off, straight in my direction, to land in a eucalyptus sapling. I still heard a Gang-gang in the first tree, and sure enough, a male landed at the hollow and also began chewing at the wood around the hollow. He did not pick at the wood for long, instead he climbed up to the top of the rump of the branch, where he called a few times.