This spot may have had two nests, maybe Egrets from last year since they will nest very close.
I didn’t see when this second Heron came in, but it must have been just a moment before I started to shot.

The bird with the higher, and better position for a fight became aggressive. The new comer just didn’t react.

A big question here. Was this a female stopping by to visit?
Truth is there is little obvious difference between the sexes, especially when they are growing their breeding feathers. The male is larger with a longer bill. This is in the wild, in a rookery tree, so good luck with an ID until you see them mate.

Ultimately there was no confrontation. Both just sat there.
Again the big question…