I grew up calling this bird the Louisiana Heron but then someone rightly decided that it was inappropriate to name a species distributed all the way from coastal New Jersey to Peru and Brazil after a US state. Nowadays it's the Tricolored Heron, EGRETTA TRICOLOR. It's so common along southern US shores that I wouldn't mention it now, except that I also got a good picture of it, which you can see below:
Tricolored Herons differ from the Little Blue Herons and Great Blue Herons by having "white britches." Also, unlike the Little Blue, a white stripe with rusty-red flecking descends from the throat down the front of the neck.
This bird is fun to watch at it hunts. Sometimes it stealthily stands in water waiting for prey but other times it lets loose and runs splashing across the water.