If you happen to see a tree which has a lot of scratches on the bark, look up! Especially if it is a Messmate tree but not necessarily. Koalas often use the same tree for sleeping in and will scratch the bark as they climb up with their big claws.
Owl trees often have regurgitated food at the base of the tree as they splat it down, such as possum bones or whatever they didn’t digest. A Powerful Owl is big enough to take feral cats! I think that when you are in the forest, looking at the ground occasionally can yield more interest than looking up. The animals may hide, but their traces don’t.