Great Blue Herons nest mainly in trees, but will also nest on the ground, on bushes, in mangroves, and on structures such as duck blinds, channel markers, or artificial nest platforms. Males arrive at the colony and settle on nest sites; from there, they court passing females. Colonies can consist of 500 or more individual nests, with multiple nests per tree built 100 or more feet off the ground.
Male Great Blue Herons collect much of the nest material, gathering sticks from the ground and nearby shrubs and trees, and from unguarded and abandoned nests, and presenting them to the female. She weaves a platform and a saucer-shaped nest cup, lining it with pine needles, moss, reeds, dry grass, mangrove leaves, or small twigs. Nest building can take from 3 days up to 2 weeks; the finished nest can range from a simple platform measuring 20 inches across to more elaborate structures used over multiple years, reaching 4 feet across and nearly 3.5 feet deep. Ground-nesting herons use vegetation such as salt grass to form the nest.
Pale blue, fading slightly with age.
Condition at Hatching
Bluish eyes open, chick covered in pale gray down, able to vocalize.
Great Blue Herons eat nearly anything within striking distance, including fish, amphibians, reptiles, small mammals, insects, and other birds. They grab smaller prey in their strong mandibles or use their dagger-like bills to impale larger fish, often shaking them to break or relax the sharp spines before gulping them down.
Great Blue Herons are most vocal on the breeding grounds, where they greet their partner with squawking roh-roh-rohs in a “landing call” when arriving at the nest. A disturbance can trigger a series of clucking go-go-gos, building to a rapid frawnk squawk that can last up to 20 seconds. If directly threatened, birds react with a screaming awk lasting just over 2 seconds. Chicks give a tik-tik-tik call within minutes of hatching.more sounds
About the Herons
Though neither bird is banded, you can identify the male by the absence of a hallux (the rear-facing toe) on his right foot. Adult herons can be up to 4.5 feet tall, with a wingspan that ranges up to 6 feet. Despite their large size, they typically only weigh around 5 pounds.
Herons usually lay 2-4 eggs and share incubation duties for 25-30 days. Incubation begins with the first egg, and the young hatch asynchronously (not at the same time) over 2-5 days. After hatching, it’ll take 7-8 weeks before they fly from the nest for the first time.
About the Nest
This Great Blue Heron nest is in a giant white-oak snag in the middle of Sapsucker Woods pond (click for aerial view), right outside the Cornell Lab’s Johnson Center for Birds and Biodiversity in Sapsucker Woods. In 2009, the arrival of those first twigs marked the start of the first known Great Blue Heron nest in the history of Sapsucker Woods. Early in the spring of 2012 we installed two cameras to bring the hidden world of their nesting habits into full view. The nest itself is nearly four feet across and a foot deep, and wraps almost entirely around the trunk of the tree. The birds have slowly built up the nest over the last few years.
About Sapsucker Woods
Sapsucker Woods Sanctuary was named in 1909 by famed bird artist Louis Agassiz Fuertes upon finding the first Yellow-bellied Sapsucker nest in the Ithaca region. About 3 miles from Cornell’s campus, Sapsucker Woods covers 230 acres of forest dominated by red maples, beech, and hickory, including the 10-acre pond that hosts the herons’ nest site.