Gang gangs working on a hollow. The male spent a lot of the time in the hollow with only his tail feathers sticking out, and the female sat just above the hollow keenly observing what he was doing. They were regularly interrupted by a Currawong which would fly in and disturb them, and then the Gang gangs would chase it away and then resume their positions at the hollow. I was watching from about 40 metres away and as I went to leave the male Gang gang flew low and directly at me and swooped over my head and sat in a tree directly above me. It felt like an aggressive act, it could have been coincidental, but it didn't seem like it.