New York Natural Heritage Program
Great Blue Heron
Ardea herodias Linnaeus, 1758

Identifying Characteristics [-]
Great Blue Herons are large, gray-blue birds with long brownish or green legs and long "s"-shaped necks. They measure 97-113 centimeters (38-54 inches) in height. Their wingspan is between 167 centimeters (66 inches) and 201 centimeters (79 inches) and they can weigh 2100-2500 grams (74.12-88.25 ounces). Great Blue Herons have a white forehead with a black stripe that extends above the eye and a white foreneck streaked with black. The bill is thick and yellowish. Eyes are yellow. During the breeding season, adults have ornate plumes on their head, neck, and back. Non-breeding adults do not have ornate plumes and their bill is more yellow. Sexes are similar. Juveniles have a black crown without ornate plumes. Great Blue Herons typically nest in colonies, also known as heronries or rookeries, but can also be solitary nesters. Nests vary in size from 0.5 meters (19 inches) across to 0.9-1.2 meters (3-4 feet) across. They build their nest out of sticks and line the shallow depression with fine twigs, moss, pine needles, or grass. The birds continue to add materials to the nest during incubation through rearing their young. Nests are usually 7.6-30.5 meters (25-100 feet) off the ground. Eggs are a dull, pale blue. The clutch size is typically 2-6 eggs. The Great Blue Heron call is a deep, hoarse croak ("frahnk, frahnk, frahnk").
Great Blue Heron Images
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The Best Time to See
Great Blue Herons are usually present in New York year-round, but are more abundant during their breeding season from mid-April through the end of July. Generally, they tend to be crepuscular, but they can also be active during the day and night. They can be found near areas with open water usually standing still in the more shallow areas. Winter distribution is more restricted than during other seasons and varies from year to year depending on the severity of the winter weather and availability of open water.
Present Breeding
The time of year you would expect to find Great Blue Heron present (blue shading) and breeding (orange shading) in New York.
Similar Species
  • Sandhill Crane (Grus canadensis)
    The Sandhill Crane is larger than the Great Blue Heron, has a shorter bill, a red cap, and bushy feathers on the rump. Also, Sandhill Cranes are found in fields rather than aquatic areas.
  • Tricolored Heron (Egretta tricolor)
    Tricolored Herons are more slender, have white plumes on the head, and a white belly that contrasts with the dark chest.
  • Little Blue Heron (Egretta caerulea)
    Little Blue Herons are smaller and more slender than Great Blue Herons. They are also a uniform gray color and lack plumes on the head. Their bill is dark with a bluish base unlike herons whose bill is a yellowish color.