About 60 species of long-legged wading birds, classified in the family Ardeidae (order Ciconiiformes) and generally including several species usually called egrets. The Ardeidae also include the bitterns (subfamily Botaurinae). Herons are widely distributed over the world but are most common in the tropics. They usually feed while wading quietly in the shallow waters of pools, marshes, and swamps, catching frogs, fishes, and other aquatic animals. They nest in rough platforms of sticks constructed in bushes or trees near water; the nests usually are grouped in colonies called heronries.