It is not easy to make a distinct classification of individual heron/egret species, as the tiny differences between them is not that clear cut. Like wise making an ID of them, for example between the various species of Egrets which are all white in color, is not easy. The differences between Herons & Egrets, could be somewhat a little bit more straight forward. All Egrets are assumed to have white feathers [all except the Pacific Reef] So much about introducing this family, Ardeidae and back to this page  that deals with birds having Heron as their names.

Heron, too, nest as a colony in trees.

The largest Heron seen in Malaysia is the Purple Heron at 90 cm  while the Striated Heron, the smallest at 40 cm. Some features of these Herons. They are able to kink their neck into an s-shape, due to the modified shape of the sixth vertebrae. Likewise, this action of retracting and extending is also used in flight. The smaller Herons, Pond Herons or Night Herons have shorter necks. The legs, bare without feathers, are long and strong are held backwards in flight. Finally, the bills are long and harpoon like. These bills could be fine or thick. As for colors, only the Pond Heron display dimorphism in plumage.