New Jersey Endangered and Threatened Species Field Guide
Great blue heron
Species Group: Bird
State: Special Concern (Breeding)
The great blue heron is the largest wading bird in North America. It is 46 inches in length with a wingspan of 72 inches. It has blue-gray upperparts, a grayish neck, long legs, and a large daggerlike yellow bill. Its chin is whitish and it has a dark blue eyebrow which often ends in a tuft of dark feathers. Males and females look similar.
DISTRIBUTION AND HABITAT
The great blue heron occurs throughout most of North America, from Alaska and eastern Canada in the north to the northern portion of South America in the south. It withdraws from the northernmost portion of its range during winter. This species breeds throughout New Jersey. It generally does not occur within the northwestern corner of the state during winter.
Nesting colonies may occur in both wetland and upland habitat, but are never too far from bodies of water. It feeds in lakes, ponds, rivers, streams, and marsh. It nests near both fresh and salt water.
The great blue heron has a relatively wide diet, consuming insects, crustaceans, fish, amphibians, and even small reptiles and mammals. It feeds by standing in or alongside water, striking its prey with its bill.
The great blue heron nests colonially and usually in tall living or dead trees. The nest is a large flat platform of twigs. Nests may be used for more than a year. The nest will become larger each year as the birds add more nesting material.
Breeding begins from early March through April and usually ends in July. Each pair lays 3 to 7 eggs and incubation lasts 25 to 29 days. Both parents incubate the eggs and care for the young. The young are usually ready to fly at 60 days after hatching and will leave the nest at between 64 to 90 days. They may then breed at two years of age.
CURRENT STATUS, THREATS, AND CONSERVATION
The great blue heron’s population in North America is stable. Due to its wide distribution, varied diet, and flexibility in nesting near both freshwater and saltwater environments, it has not fared as poorly as some other wading birds. However, it is still classified as a Species of Special Concern in New Jersey (not yet endangered or threatened but on its way). Wetland destruction has caused a decrease in heron populations from their historic numbers. Since the 1950s, habitat loss has occurred at an alarming rate in New Jersey, destroying wetlands critical to breeding herons.
Like many species in New Jersey, protecting great blue herons is closely tied with protecting their wetland habitats. Strong environmental laws to protect wetlands from disturbance and development help to protect wetlands and the great blue heron.
A 2009 survey of great blue heron colonies by the New Jersey Endangered and Nongame Species Program found 31 active nesting colonies in the state that year. Within those colonies, a total of 586 individual nests were counted.
We still have much to learn about the biology and population status of great blue herons in New Jersey. Research needs to be completed to find additional breeding sites, check existing nesting areas, and determine whether the population might be decreasing or increasing.
Text written by Michael J. Davenport in 2011.
Species: A. herodias
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