Great Blue Heron

Ardea herodias

Great Blue Herons at Fort De Soto

What are we studying?

Great blue herons (Ardea herodias) are large, wading birds that primary forage on fish. While we believe they mainly forage during the day, they are one of the only wading birds in their genus who forages at night. We are studying habitat, degree of luminosity, and tide of when they nocturnally forage.

About Great Blue Herons

Blue morph

Identification

Great blue herons are the largest heron in North America with a height of 160cm, or 5ft 2in. They have two morphotypes: a white morph and a blue morph. The blue morph has a grey body. Its head is mostly white with a wide dark blue stripe running from above its eyes to the back of its head. The white morph is completely white. They can be misidentified as a great egret, however these birds have a larger, heftier bill. Great blue herons have a long, tapered bill -- the top bill is dark and the bottom bill is yellow. Both have yellow eyes and brownish or greenish legs.

White morph

⭐ Fun Fact: The great blue heron is one of the most widespread wading bird in North America! ⭐

Habitat

Great blue herons can be found all across North America -- from the south eastern coast of Alaska to Nova Scotia and as far south as the north coasts of Panama, Colombia, and Venezuela. Great blue herons are very adaptable. They forage in wetlands and water bodies but can be found occasionally in upland areas or any commercial areas where fish scraps can be found. They nest in trees, bushes, on the ground, and on artificial structures, usually near water. However, it has been found that great blue herons in different parts of North America favor some sites over the other. Here in Florida, they usually use mangrove islands for nesting.

Great blue heron in the small stream at the entrance to the beach at Pavilion 1 & 2

Great blue heron wading amongst mangroves

Great blue heron foraging at low tide on the beach

⭐ Fun Fact: The great blue heron is one of the only wading birds in their genus (Ardea) that forages at night! ⭐

Foraging

While they are the only bird in their genus that forages at night, they also forage during the day. Great blue herons mainly eat fish but can also eat amphibians, crustaceans, reptiles, mammals, insects, and other birds. While hunting, these birds slowly wade or stand in shallow water and ebbing or low tides. They then catch their prey by rapidly thrusting their neck. Most prey is swallowed whole.

Watch the videos below to see them in action!

Conservation

According to the IUCN Red List of Threatened Species in 2020, the great blue heron has been listed as least concern! Some threats to current populations include new chemical contaminants being released into the environment, destruction and degradation of habitat, and disturbance of nesting and foraging areas. Although populations are strong, restoring tidal marshes and other habitats as well as protecting these habitats can help the great blue heron.

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