Two or three times a year I see this gathering of large numbers of egrets and herons. Usually either a fish kill or a fish spawning was the attracting factor. I did not see any dead fish this day but did see a large amount of tiny silver shad in the waters. In this shot you have a lot of snowy egrets with a couple of great egrets mixed in. The snowies are very territorial which explains all those ruffled feathers as they try to intimidate each other.
Great Egret (Ardea alba)
Snowy Egret (Egretta thula)