Crows are smart.
These two were not happy about a possum being in their tree, so they are tag teaming it. Pulling it's tail, harassing back and foward to keep safe but to annoy the bejebus out of the poor possum. I can't see any nests for the crows, but a magpie family lives there and shortly after this it started swooping all involved. Nature-based free-for-all today.