Sorry, this sighting is a bit late. These birds were in two groups, three in one and two in the other, in two different trees. The group of two were about mid-way in some sheoaks just off the trail, but I couldn't take a decent photo because of the clutter of branches. The uploaded photos may not be clear but hopefully in some of the photos you can see the red tail feathers of the birds. They were calling among themselves and I have regularly heard the Yellow-tailed Black-cockatoo but this call was different and that made me stop to have a closer look.