This had all the makings of a territorial confrontation.
A Great Blue Heron was there fishing and the Great Egret walked by a little too close. The Heron has the advantage, the Egret also a large predator was not backing down.
As the Great Egret got closer he postured for the Great Blue. The Heron just turned along with him.
Making the right decision, the Egret kept walking by.
Whenever there are two big predators it’s almost always bluff, if it’s not mating season.