Northern Prairie Wildlife Research Center
GREAT BLUE HERON Ardea herodias L46"(117cm)
This large gray-blue bird is the best known, most widespread, and largest of all North American herons. An adult great blue heron can reach 52 inches in height and have a wingspan of seven feet. It can be recognized in flight by its large size, broad wingspan, and head and neck folded back in an S-shape to the shoulders. It is an excellent predator, often seen standing alone and motionless on the edges of marshes and rivers waiting for prey. Its main prey is small nongame fish but it will readily take frogs, snakes, salamanders, and shrews. The great blue heron often nests in colonies or small groups with the nest being placed high in a tree. Nests are constructed of large twigs and lined with marsh grass, pine needles, and mosses. The female lays 3-7 pale blue-green eggs with both sexes sharing incubation duties. The incubation period lasts approximately 28 days and an incubating heron will turn its eggs by rolling them with the bill once every two hours. The turning of the eggs helps to keep all of them at even temperatures and prevents the embryos from sticking to the inside of the eggshells.