[order] Ciconiiformes | [family] Ardeidae | [latin] Ardea herodias | [UK] Great Blue Heron | [FR] Grand Héron | [DE] Kanadareiher | [ES] Garza Azulada | [IT] Airone azzurro maggiore | [NL] Amerikaanse Blauwe Reiger

Amerikaanse Blauwe Reiger determination

copyright: Bill Wayman

Great blue herons are the largest herons in North America. They stand approximately 60 cm tall and are 97 to 137 cm long. They weigh 2.1 to 2.5 kg. They have long, rounded wings, long bills that taper to a point at the end, and short tails. They also have very long necks and legs. The bills are a yellowish color and the legs are green. Great blue herons have gray upper bodies, and their necks are streaked with white, black and rust-brown. They have grey feathers on the back of their necks with chestnut colored feathers on their thighs. The males have a puffy plume of feathers behind their heads and also tend to be slightly larger than females.

Great blue herons always live near sources of water, including rivers, lake edges, marshes, saltwater seacoasts, and swamps. They usually nest in trees or bushes that stand near water, breeding at elevations of up to 1,500 m. They tend to avoid marine habitats along the east coast and instead live inland.

Great blue herons can be found in the Nearctic and Neotropical regions. During the spring and summer, they breed throughout North and Central America, the Caribbean, much of Canada and the Galapogos. Some populations migrate to Central and South America during the winter months, but do not breed there.

Great blue herons fish in both the night and the day, with most of their activity occurring around dawn and dusk. Herons use their long legs to wade in shallow water and their sharp "spearlike" bills to catch their food. Great blue herons' diet consists of mainly fish, but also includes frogs, salamanders, lizards, snakes, birds, small mammals, shrimps, crabs, crayfish , dragonflies, grasshoppers, and many other aquatic insects. Herons locate their food by sight and usually swallow it whole. Herons have been known to choke on prey that is too large.

This species has a large range, with an estimated global Extent of Occurrence of 9,800,000 km². The global population size has not been quantified, but it is believed to be large as the species is described as 'frequent' in at least parts of its range (Stotz et al. 1996). Global population trends have not been quantified, but the species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e. declining more than 30% in ten years or three generations). For these reasons, the species is evaluated as Least Concern. [conservation status from birdlife.org]

Great blue herons typically breed from March to May in the northern part of their range and November through April in the southern hemisphere. Females lay between 2 and 7 pale blue eggs. Birds living further north tend to have more eggs. Both parents incubate the eggs, which means that the parents take turns sitting on the nest to keep the eggs warm until they hatch. The eggs hatch after 26 to 30 days of incubation. After living in the nest for about 2 months, the babies (called chicks) are ready to fledge, which means they are old enough to leave the nest and survive on their own. Herons become sexually mature when they are about 22 months of age. Both parents care for and feed the chicks until they are ready to leave the nest. The largest chicks receive the most food.

Marked post-breeding dispersal in N America. Populations of N migratory, those of S sedentary, sometimes with local movements. Autumn migration takes birds to S USA, Cuba, West Indies, C America and N parts of S America, though some birds winter as far N as S Canada. Accidental to Greenland; Hawaii, Azores. White morph sedentary, with some wandering and post-breeding dispersal.