This is how most territory disagreements are.
One Egret will fly directly into another, sometimes from behind.
Rarely do they even touch, but I have seen some crash down to the water. These two did push with their wings.
In this meeting the bird closest to me flew up to challenge the other, who was just flying over the swamp.
A few wing flaps and one turned aside.
What was the cause I have no idea. Probably territorial since they are all breeding in this rookery. But neither was near any nests.
Great Egret are one of the most aggressive nesters in the rookeries, dangerous predators to the other birds. Great Blue Herons and Anhinga will hold their own in any confrontations.