Ardea herodias

Identifying Features

Great blue herons are the largest species of heron in North America, getting around 2 feet tall and 4 feet long. Their bodies are generally a greyish blue color with a dark crown, whitish throat, thin whitish plumes on their backs, and patches of black or rust on their sides and thighs. Juvenilles are generally much darker in coloration.

Habitat & Range

Great blue herons can be found throughout much of North America, from the southern tips on Canada down to the northern tip of South America. The northernmost populations migrate south for the winter.

Great blue herons live near the waters of lakes, marshes, swamps, and sea coasts with tall trees.

Behavior

Great blue herons are primarily pescivores, but they also opportunistically feed on small amphibians, reptiles, and invertebrates. They are stalk and strike hunters, fishing in daylight, most often morning and dusk. Though they are solitary hunters, they sleep at night in waterside trees, often in flocks of over 100. They also nest at these sites, called rookeries, which ofter protection by numbers from predators which would raid their nests.

As aquatic water, great blue herons are migratory because they must always be near accessible food sources.

Life Cycle

In the northern part of their range, great blue herons breed in March through May, and in the southern-most part of their range they breed from November through February. Males are typically monogamous for the breeding season, and breeding pairs typically with bond throughout the season. Nests are roughly made from sticks and branches and are usually among many others within a rookery.

Females lay between 2 and 7 eggs per season, with a one month incubation period. Young great blue heron reach adulthood after 22 months.

Featured image by Mike Baird