This is a detail from wider shot. The male egret in the middle was squaring off against the one on the right while the female in the background looked on. The one on the right and the female on the left had already paired for the mating season and were building their nest. The male in the middle was an interloper.
The two males fought each other for several minutes, jousting with their beaks. I took approximately thirty shots in this sequence. In the frame after this, the female put an end to the rookery fight by stabbing the interloper in the back with her beak. The interloper then fled.
I took this shot with the Nikon D4 and 800 mm f5.6 Nikkor.