Preening helps distribute this powder, which absorbs and removes fish oil, scum and slime, thus keeping the rest of the plumage clean and dry. Herons preen with a serrated middle claw. Males are aggressive and defend small territories in breeding season. Some also put on spectacular flight routines. In most species, bright colors appear on the bill, legs or in the bare skin around the eyes.
Mated herons defend a zone immediately around their nest against intrusion of other birds.
Or, in certain parts of their range, they may nest with cormorants, pelicans and ibises. Some herons begin incubating immediately after the first egg is laid, so that young hatch at intervals and differ in size. Young remain in the nest two to three weeks. At first, parents regurgitate pre-digested liquid food to their nestlings. Later, they bring partly digested food, and finally whole fish, frogs, snakes and other items.