This is a Reddish Egret (white morph), and this was the first time I had ever seen one. He was ID'd initially by his hunting technique, but further ID came from the bi-colored bill and his darker legs.
The Reddish Egret has a very unusual hunting technique (at least for a Heron/Egret), instead of patiently waiting for a fish like other Herons/Egrets, it actively peruses and forces fish into a small area by running, jumping, and spinning around in almost a ballroom dancing motion. After the fish are tightly balled up it strikes into the center of the ball and catches a fish.
Here in the Gulf of Mexico (where I took this picture), White Morph Reddish Egrets compose about 3 to 4% of the total Reddish Egret population.
