Ardea herodias
Zhashagi (Ojibwe)
Large, common, and widespread, the Great Blue Heron is perhaps the most familiar wading bird in North America. You might find it foraging near Green Herons and Red-winged Blackbirds in a wetland, with Sanderlings and Great Egrets on a seashore, or even spearing koi in a backyard pond. Great Blue Herons are tall and statuesque, often standing stock-still for long stretches of time as they survey the water around them for prey. When they spot their prey, however, they move extraordinarily fast — blink, and you’ll miss them!
The Great Blue Heron is an adaptable species, and its population is increasing in an era when many other bird species are in trouble. It was aggressively hunted for its plumes in the late 19th and early 20th centuries, but protections from the Migratory Bird Treaty Act and other laws and regulations have helped this magnificent bird’s population recover. Still, the Great Blue Heron is vulnerable to the loss of valuable wetland habitat and impacts from pesticides and toxins.
Great Blue Herons were hunted for their plumes until the early 20th century, but they are now protected under the Migratory Bird Treaty Act. Herons have also been impacted by chemical pollutants, including pesticides, industrial chemicals, and even commercially available chemicals. Now, herons are faced with extensive habitat loss and disruption. Wetlands, where herons forage, are filled and drained to make way for development. Furthermore, development near rookeries can cause herons to abandon historical colonies.
Across North America, wetlands are being drained, water quality is declining, and heron nesting areas are disturbed by development and human recreational activities. Although Great Blue Herons are adaptable, ongoing land-use change, especially along shorelines, is a continual threat.
Though better regulations have reduced the amount of industrial waste in the environment, chemicals leaching from consumer products pose an increasing threat. Studies have found that levels of polybrominated diphenyl ethers, a chemical flame retardant, are increasing rapidly in heron body tissues, and are reaching the point where they are expected to have negative impacts.
Birds need our help to overcome the threats they face. At ABC, we’re inspired by the wonder of birds and driven by our responsibility to find solutions to meet their greatest challenges. With science as our foundation, and with inclusion and partnership at the heart of all we do, we take bold action for birds across the Americas.
Wetlands are biodiversity powerhouses wherever they occur, but these habitats are frequently drained or destroyed by new development. American Bird Conservancy and other conservation groups are working across North America to protect and restore the continent’s wetland habitats and the birds that call these places home.
ABC works with partners at the state and federal levels in the U.S. to call for the regulation or cancellation of the toxins most harmful to birds, and advocate for strengthening existing laws that help birds like the Great Blue Heron. We develop innovative programs and carry out research to better understand the toll pesticides and toxins take on birds, and identify solutions.
Though they are usually silent, Great Blue Herons will sound off when disturbed. Vocalizations are mostly quite loud and harsh, ranging from sharp squawks to guttural croaking calls. Breeding colonies, or rookeries, are often quite noisy with begging juveniles and displaying adults.
Credit: Greg Irving, XC1040454. Accessible at https://xeno-canto.org/1040454.
Credit: Christopher McPherson, XC445084. Accessible at www.xeno-canto.org/445084.
Highly adaptable, the Great Blue Heron inhabits marshes, swamps, lakeshores, riversides, beaches, and ponds. Herons also forage in upland areas and prairies, especially in winter.
Specific Area
Southern Alaska and Canada, south to Venezuela and Colombia, the Caribbean, the Galápagos
Range Detail
At some point during the year, the Great Blue Heron can be found near just about any body of water throughout North America. This bird breeds from southern Alaska, across central Canada to Nova Scotia, south to parts of the Caribbean and northern Mexico (rarely in northern Belize, as well). The northern breeding population migrates to warmer climes for the coldest months. During the winter, the Great Blue Heron is found across Mexico, Central America, and the Caribbean, reaching the northern coast of South America. A resident population lives in the Galápagos archipelago.
The Great Blue Heron will eat whatever it can catch with its formidable bill: fish, crustaceans, reptiles, amphibians, small mammals, and birds — especially ducklings. Herons usually forage alone, walking slowly or standing stock-still in wait. Once prey is in range, a heron strikes quickly, straightening its long, powerful neck and grabbing or impaling its quarry with its spear-like bill, then swallowing it whole. Excellent night vision allows this versatile wading bird to hunt in darkness as well as in daylight.
Great Blue Herons are monogamous during the breeding season, but form new pairs each year. Courtship begins as the male selects a nest site, then displays to attract a female, extending his neck while spreading out his specialized neck feathers (“nuptial plumes”) and shaking twigs held in his bill. He may also fly in a circle around the potential nest site. Once he attracts a female, the pair will bond through continued displays: twining necks, clattering bills together, and raising their nuptial plumes.
The Great Blue Heron nests in large colonies, or rookeries, that can include up to several hundred pairs. Rookeries are usually located high in trees near or above water, and sometimes on islands, to discourage predation by reptiles and mammals. Sometimes pairs nest in lower shrubs and bushes, or even on the ground. Nesting herons may even accept human-provided platforms if they prove safe from predators. Pairs often return to the same colony and reuse nests from previous years. The male brings sticks and branches to the female as she begins her nest, a rough platform lined with softer materials such as moss or dry grass.
Once the nest is complete, the female lays three to six pale blue eggs, which both parents incubate for about a month. The young hatch with open eyes and down-covered backs, heads, and sides. Both parents feed their offspring by regurgitating food, and the young leave the nest two to three months after hatching. Once fledged, the young birds remain dependent on their parents for food for about another three weeks.
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