Great Blue Heron (Ardea herodias)


Class: Aves
Order: Ciconiiformes
Family:    Ardeidae
Size:    Height: 36 to 48 inches  (91 to 122 cm) Wingspan: 68 to 76 inches (173 to 193 cm)
Weight: Up to 8 pounds (3.6 km)
Diet: Fish, frogs, lizards, snakes, crustaceans, insects and rodents
Distribution: North and Central America, the Caribbean and the Galapagos Islands
Young:  3 to 5 chicks, once a year
Animal Predators:  Unknown
IUCN Status: No special status
Terms: Young: Chick
Lifespan: Up to 25 years in the wild



·     The great blue heron is the largest and most common heron in North America.

·     It is often mistaken for a crane, which is similar, but the crane flies with its neck extended.

·     Great blue herons build their nests in colonies called “heronries.”

·     Great blues fly between 20 to 30 miles (32 to 48 km) per hour.



Great blue herons have a long neck, long legs, a sharp bill and a short tail. They have mainly greyish-blue upper parts and black and white markings on the crown and undersides. They stand with their neck bent in the shape of an S, and when they fly, their legs trail loosely behind them and the neck remains in the S shape, with the head touching the shoulders rather than stretching out in front.



Great blue herons can be found throughout North America during the summer months. They migrate south to Central America, the Caribbean and the Galapagos during cold weather, although in British Columbia, where the winters are milder, many remain year round. Great blue herons can be found living near rivers, lakes, marshes, swamps and saltwater coasts. 


Feeding Habits

They frequent both saltwater and fresh water, and their diets include fish, frogs, lizards, snakes, crustaceans and insects. Blue herons hunt by walking through the water, hoping to drive fish out of hiding. If none appear, they fly a few feet away and try again. Blue herons also sometimes hunt on land, catching small rodents. 



Great blue herons arrive north in the spring and usually settle in much the same area as the previous year. Blue herons live away from human settlements, in woods close to a lake or river. The males put on loud mating displays when approached by females. New monogamous pair relationships are formed each year. The couple make their nest in a treetop and sometimes they just restore an old nest rather than start from scratch. The male gathers dry twigs and branches, while the female puts the nest together and lines it with moss and pine needles. The nest is usually fairly large, up to three feet (91 cm) in diameter. Construction takes about a week, and then the female lays three to five pale blue eggs. Both the male and female take turns incubating the eggs until they hatch approximately one month later. Both parents feed the young—the male stays with the chicks during the day to make sure they are safe, while the female hunts for food and brings it back to the nest. At night, the male hunts while the female stays with the chicks. In two weeks, the chicks begin to stand up and move their wings, as well as clean their feathers. When the chicks are a month old, the parents leave them alone for periods of time and at six weeks, the chicks begin to walk on the surrounding branches, preparing for their first flight. At eight weeks, they take short flights, but still return to the nest for feeding. At 10 weeks, the young herons are able to leave the nests and become independent. 



These quiet, majestic birds can often be seen standing motionless in water. Up to 90 percent of their day is spent searching for food. They rarely emit sounds, unless disturbed (“kraack” or “frahnk”); greeting other herons (“ahr”); or during mating season. Blue herons are sociable birds and sometimes can be found in large flocks.



In Canada, the subspecies Ardea herodias fannini, found on the Pacific coast, is listed as Special Concern by Environment Canada. They are protected from hunting by the federal Migratory Birds Convention Act of 1917 and the Migratory Birds Regulations (this includes protection of nests, eggs, young, and adults). Human activity in the vicinity of heron colonies poses the largest threat to the Pacific population. 



National Geographic Field Guide to the Birds of North America, Third Ed. (1999)