A Guide to Common Animals of Western North America

Great Blue Heron - Ardea herodias Distribution: The great blue heron is distributed from the southwestern coast of Alaska eastwards through boreal Canada to Nova Scotia, south through Florida, the Gulf Coast States, Mexico and the Caribbean to South America. Habitat: The great blue heron inhabits lake margins, mangroves, fresh and saltwater marshes, flooded meadows, ponds, rivers, shorelines in general, and swamps. Characteristics: The great blue heron is a large, grayish wading bird with a mostly S-shaped neck. Their bluish-gray slate colored back, belly, and wing feathers contrast those of the reddish-rusty-gray neck that is streaked down the front in black and white. The lower neck feathers are long and plume-like, or shaggy, as are those on the lower back. Their thighs are more or less red-brown in color. The head is pale, the face is white, and black plumes extend from the yellow eyes to the back of the head. The top of the head is crowned with a white stripe. The long, thick bill is dull yellow-orange in color below and darker above. These largest of the North American heron are long legged and measure 0.9-1.4 m bill to tail tip, have a wingspan of 1.6-2 m, and weigh 2-3.6 kg. Diet: Small fish represent a large part of the great blue heron diet, as do mice. Miscellaneous amphibians like frogs, salamanders, and toads, small birds, crabs, crayfish, dragonflies, grasshoppers, aquatic insects, lizards, small mammals like rodents, shrimp, snakes, and turtles are also part of their diet. Reproductive Biology: The great blue heron reaches sexual maturity at about 22 months of age. Breeding occurs from March-May. Despite the fact that the great blue heron is generally a solitary bird, breeding occurs in colonies or heronries (singular heronry) that may consist of hundreds of nests. Although monogamous in any given breeding season males and females do not pair for life. Only a single brood is produced in any given year. Large, 1 m by 1 m stick nests are constructed in the tops of trees, bushes, or cliff edges close to the water’s edge. The female lays 3-6 pale blue eggs that measure 10-15 cm in length. Both male and female incubate the eggs over the next 25-30 days. Hatching is asynchronous and occurs over several days. Both male and female feed the young regurgitated food though the lion=s share is taken by the eldest. After 60 days the young fledge. Behavior: Not all great blue heron migrate in the fall. Although they do hunt alone, nesting occurs in heronries. When in search of prey the heron will stand motionless until it sees movement, and then it will strike. Points of Interest: A male heron is called a cock, a female is referred to as a hen, and the young are known as chicks. Although a breeding colony of herons is called a heronry, a group of herons is a battery, hedge, pose, or scattering. Despite the fact that first-year survival approaches only about 10%, the great blue heron may live for 10+ years. Flight speeds generally range from 32-48 kph. Generally speaking these are skittish birds that do not accept being approached.