Mating and Nesting

MATING: Green Herons mate in monogamous pairs each season. Exactly when breeding season begins depends on the region the herons are located; it can be as early as March or late as July. During this process pairs go through an elaborate series of courtship displays with unique calls. These displays include:

Flying Around display: Resembles normal flight around the breeding area while emitting a skow call.

Pursuit Flight, Circle Flight, and Forward displays: Flight continues but uses a rasping ‘raah-raah’ call that exposes the red lining of the mouth.

Crooked-Neck Flight displays: The male herons flex their necks, dangle their legs, and beat wings in a way that produces a noticeable sound.

Flap Flight display: A more intense continuation of the Crooked-Neck Flight display. The male’s wing beats make a whom-whom-whom sound and he stands his crest, neck and shoulder feathers erect while still flying in crooked neck posture. Before landing he makes a 'roo-roo' call.

Snap display: a non flying display in which the male perches and points his body, neck, and head downward. With his bill at or below the level of his feet and his feathers erect, the male heron snaps his bill and produces a clicking sound.

Stretch display: Begins with the male stretching his neck and pointing his bill straight up, followed by bending his neck backwards almost to the point where his head is touching the erect feathers of his shoulder plume. Then he will sway his neck back and forth while making an 'aaroo-aaroo' sound and bulging his eyes.

After the males finish the Stretch display the females are allowed to enter the nest area prepared by the male. She will also perform a less intense Stretch display to confirm the pair-bond.

NESTING: Green herons are not known for their nest building skills, and are in fact some of the worst nest builders in the heron family. They nest anywhere from 10 to 30 feet off the ground, yet their light greenish blue eggs are often visible from ground-level due to the loose construction of their nests.
 
The males select the nest site before pairing and construction begins afterwards. The male brings twigs to the female, who then handles the actual construction. Unlike other heron spices, green herons aren’t very colonial, so usually there will be only one nest per tree. If egrets, ibises, or other heron species are in the area, the green heron will nest in areas these larger birds are unable to penetrate, usually under a canopy of foliage.

Females can lay up to 7 eggs, but usually will only lie between 2 and 4. The male and female take turns on the nest during the 19 to 21 day incubation period. Chicks emerge covered in a grayish down and are very good climbers. By the time they are one to two weeks old they begin to venture out of the nest using their wings and beaks to climb. When the chicks are still young the parents feed them by first regurgitating food into the nest and then picking up small bits of food to drop in the waiting chicks’ mouths. As they grow older, the parents will regurgitate the food directly into their beaks. Young herons make their first flight when they are about 22 days old, and become independent at 30 to 35 days.