The Great Blue Herons of Southern Florida

Article and Images by Arlene Spagna

The Great Blue Herons of Southern Florida - Arlene Spagna
© Arlene Spagna, Field Contributor
The largest heron in North America—the Great Blue—lives, breeds and nests year-round in South Florida, so I have the opportunity to photograph them in every season.

They are wading birds with long legs and an s-curved neck, with a white crown and face and a black plume. The adults have a brownish buff neck with black bordered white stripes down the center of the forehead. Great Blues have a blue-gray back and wings.

Their greenish/yellow legs and large yellow bill make it easy to tell them apart from a great egret, another large bird in the heron family (Ardeidae). The Great Blues (Ardea Herodias) stand three and a half to four and a half feet tall, with a wingspan of five and a half to six and a half feet. The immature Great Blues have a black cap, brownish-gray back and upper wings, but lack the shaggy neck and black plume.

The Great Blue Herons of Southern Florida - Arlene Spagna
© Arlene Spagna, Field Contributor
Their breeding habitat is in Wetlands and open water. The Great Blues always live near water sources, rivers, lakes, marshes, swamps, and saltwater seacoasts. They usually nest in trees or bushes near water and can breed up to elevations of over 4,000 feet.

The Great Blue Heron’s lifespan in the wild is about 15 years or longer and they are most vulnerable when they are young. More than half the Great Blues born in one year will die in their first year: some from being the smallest or weakest in the brood, some from predators such as ravens, raccoons, vultures, red-tailed hawks.

The primary diet of the Great Blue Herons are fish they locate by sight, using their sharp spear-like bills to catch the fish which they then usually swallow whole. They also feed on frogs, lizards, snakes, crabs, aquatic insects and small mammals such as mice. Great Blue Herons are most active at dawn and dusk.

The Great Blue Herons of Southern Florida - Arlene Spagna
© Arlene Spagna, Field Contributor
The Great Blue Heron is one of about 12 heron species in the Ardeidae Family, which include: American Bitterns, Least Bitterns, (smallest heron); Green Heron; Little Blue Heron, (solid blue, but the immatures are in a white morph phase until adulthood); Tri-Colored Heron, (the immatures are brown); Black-Crowned Night Heron; Yellow-Crowned Night Heron; Snowy Egret; and Great Egret, (2nd largest heron to the Great Blues).

Male and female Great Blues are similar, with the males being larger than the females. Their sexual activity starts at 22 months.

The clutch size—the set of eggs laid at one time—is three to six eggs. Both parents incubate the eggs, taking turns to keep them warm and turning the eggs with their bills.

After 28 days the eggs are ready to hatch. Both parents care for and feed the chicks, the largest chicks receiving the most food. Great Blue chicks are ready to fledge the nest and survive on their own in about 56-60 days.

The Great Blue Herons of Southern Florida - Arlene Spagna
© Arlene Spagna, Field Contributor
The Great Blue Herons are quiet compared to other related species, but are known to have up to seven different calls. They release a soft “kraak” when disturbed in flight, a “fraunk” sound lasting about 20 seconds when disturbed near their nests, and an “ar” sound when greeting other members of their species.

Last, there is a sub-species of the Great Blue Herons called Ardea Herodias Occidentalis and is known as the White Morph form. This morph is found only in South Florida and the Caribbean. In Florida where the white and blue forms of the Great Blues overlap, an intermediate bird known as the Wurdemann’s Heron can be found, although somewhat rare. They have the body of Great Blues, but the white and neck of the Great White Heron.

The Great Blue Herons are graceful in flight and are a delight to watch and enjoy their courting, nesting and feeding habits in their natural environment here in South Florida.
 
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