A great blue heron forages along the banks of a marsh.
A great blue heron forages along the banks of a marsh.
Courtesy: E. Marks, Audubon Society of Rhode Island

Great Blue Heron (Ardea herodias)

Field markings: 46 inches long, with a wingspan of 72 inches. A large grayish-blue wading bird with a long, white neck with black streaks.
Habitat: Marshes, wetlands, shores, and tidal flats.
Seasonal appearance: Summer, fall; winter.


The great blue heron is the largest heron in North America. They grow to 46 inches long and have a wingspan of 72 inches. Even though they are large birds, they are lighter than they appear, with average adult weights of 5 to 8 pounds. Great blue herons have grayish-blue plumage with long white necks sometimes streaked with black.

Life History and Behavior

Great blue herons nest together in colonies or sometimes with other species of wading birds. They build their nests up to 130 feet from the ground in dead trees or shrubs found in flooded, forested areas, and they are commonly seen along the edges of coastal waters and rivers.

In flight, great blue herons are recognizable by their size and silhouette, flying with their long necks tucked in. Swans and geese fly with their necks extended. They fly with slow sweeping wing beats and hover for shallow-water landings. These birds forage for fish and amphibians by sweeping the water with their open bills. Contact with prey triggers a reflexive snapping of the bill closed, quickly snaring their prey. They will also stand motionless, waiting to stab at swimming prey. Their diet consists mainly of fish, but they will eat other food such as human food scraps, crabs, crayfish, nestlings, and small mammals. It is uncertain why, but great blue herons occasionally try to eat fish that are too large to swallow. The fish can become lodged in the heron's throat and may cause the bird to choke to death.

Special Designation The Rhode Island Natural Heritage Program currently lists the great blue heron as a species of special concern in the state.

Special Notes

Adapted from The Uncommon Guide to Common Life on Narragansett Bay. Save The Bay, 1998.