Whether poised at a river bend or cruising the coastline with slow, deep wingbeats, the Great Blue Heron is a majestic sight. This stately heron with its subtle blue-gray plumage often stands motionless as it scans for prey or wades belly deep with long, deliberate steps. They may move slowly, but Great Blue Herons can strike like lightning to grab a fish or snap up a gopher. In flight, look for this widespread heron’s tucked-in neck and long legs trailing out behind. Herons of all type can stand motionless for long periods of time. This gives the patient photographer some wonderful opportunities to get some fantastic Great Blue Heron Photographs.
Largest of the North American herons with long legs, a sinuous neck, and thick, daggerlike bill. Head, chest, and wing plumes give a shaggy appearance. In flight, the Great Blue Heron curls its neck into a tight “S” shape; its wings are broad and rounded and its legs trail well beyond the tail. Great Blue Herons appear blue-gray from a distance, with a wide black stripe over the eye. In flight, the upper side of the wing is two-toned: pale on the forewing and darker on the flight feathers. A pure white subspecies occurs in coastal southern Florida. It has head-to-tail length of 91–137 cm (36–54 in), a wingspan of 167–201 cm (66–79 in), a height of 115–138 cm (45–54 in), and a weight of 2.1–3.6 kg (4.6–7.9 lb).
Great Blue Herons normally feed on fish but will also take shrimp, crabs, rodents and other small mammals, amphibians, reptiles, small birds. Basically they will eat anything they think they can swallow. Generally they feed alone and will defend their territory against other herons. However, sometimes they gather together in beneficial groups that might coral a school of fish into a given area.
Blue Herons breed in colonies of various size, known as a Heronry. They can be quite large, anywhere from 5-500 with the normal number of around 160 nests. They are usually located fairly close to a food source. Herons do not mate for life and usually find a different mate and nest each breeding season. The nest of made out of lose sticks woven together by the female. They can get to be several feet across and up to 4 feet deep. Quite often they are lined with pine needles, moss, reeds, dry grass, mangrove leaves, or small twigs. Nest building can take from 3 days up to 2 weeks. Once nest building and mating are finished she will lay 3-7 eggs with 5 being the norm over a two day interval. Both sexes take turns incubating the eggs. They hatch after about 27 days and the first ones get a good head start over the last ones to hatch. After about 55 days at the northern edge of the range (Alberta) and 80 days at the southern edge of the range (California), young herons take their first flight. They will return to the nest to be fed for about another 3 weeks, following adults back from foraging grounds.
Great Blue Heron numbers are generally stable and in some places increasing across the U.S. Some local population declines have occurred, particularly in the “great white heron” group in southern Florida, where elevated mercury levels in local waterways may be a factor. Because they depend on wetlands for feeding and on relatively undisturbed sites for breeding, Great Blue Herons are vulnerable to habitat loss and to impacts such as traffic, logging, motorboats, and other human intrusions that can disrupt nesting colonies. Other threats include chemical pollutants or other causes of reduced water quality. Although contaminant levels have declined in many areas, pollutants such as PCBs and DDT and newer types of industrial chemicals continue to affect heron habitats and can contribute to factors such as reduced nest site attendance.
References: Wikipedia, Cornell Lab of Ornithology