- 22–29.1 in
- 39.4–41.3 in
- 10.4–14.5 oz
- Smaller than a Great Blue Heron; about the size of a Snowy Egret.
- Petit héron bleu, Aigrette bleue, Crabier bleu (French)
- Garza azul, Garceta azul (Spanish)
- During the feathered-hat fashion craze of the early twentieth century, Little Blue Herons’ lack of showy “aigrette plumes” saved them from the hunting frenzy that decimated other heron and egret populations.
- Little Blue Herons may gain a survival advantage by wearing white during their first year of life. Immature birds are likelier than their blue elders to be tolerated by Snowy Egrets—and in the egrets’ company, they catch more fish. Mingling in mixed-species flocks of white herons, immature Little Blue Herons probably also acquire extra protection against predators.
- With their patchy white-and-blue appearance, Little Blue Herons in transition from the white first-year stage to blue adult plumage are often referred to as “Calico,” “Pied,” or “Piebald.”
- When observing groups of white herons and egrets foraging together, look for the slow, deliberate movements of an immature Little Blue Heron. This stately and deliberate pace helps distinguish the Little Blue Heron from its relatives, which tend to move more quickly or erratically.
- A row of built-in “teeth” along the Little Blue Heron’s middle toe serves as a grooming comb. The bird uses this handy tool to scratch its head, neck, and throat.
- The oldest known Little Blue Heron was at least 13 years, 11 months old. It was banded in 1957 in Virginia, and found in Maryland in 1971.
Little Blue Herons nest and forage in many kinds of wetlands, including swamps, marshes, ponds, streams, lagoons, tidal flats, canals, ditches, fish hatcheries, and flooded fields. They nest mostly in shrubs and small trees in standing water or upland sites on islands, including artificial islands created from dredged material. Rarely, they seek prey in upland pasture sites. They usually forage in water 2–6 inches deep, often gravitating toward densely vegetated foraging sites. In wintertime, Little Blue Herons make especially frequent use of mangroves, lagoons, salt ponds, mudflats, and savannas.
Little Blue Herons eat mostly small fish, supplemented by a variety of small amphibians as well as crustaceans, grasshoppers, dragonflies and other invertebrates. Types of fish prey vary by region, and may include anchovies, killifish, gobies, perch, darters, bass, minnows, carp, and others. Invertebrate prey may include crayfish, prawns, isopods, crabs, and a wide variety of insects.
- Clutch Size
- 3–4 eggs
- Number of Broods
- 1 broods
- Egg Length
- 1.6–2 in
- Egg Width
- 1.2–1.4 in
- Incubation Period
- 22–23 days
- Nestling Period
- 35–49 days
- Egg Description
- Pale bluish green.
- Condition at Hatching
- Hatchlings are covered with sparse white down, eyes partially open.
After pairing up, a male and female spend 3–5 days building a porous platform nest of long, mostly leafless twigs and sticks lined with greener vegetation. Usually the male finds nesting material and passes it to the female, who constructs the bulk of the nest; he occasionally assists her, or performs ritual twig-shaking displays nearby. The nest has an outside diameter of 1–1.5 feet.
Little Blue Herons nest in low shrubs and small trees, in protected areas below the canopy. They may also choose flooded areas or islands as added protection against predators. Little Blue Herons and neighboring colonial birds have a pronounced impact on their nesting habitat—stunting the growth of vegetation by harvesting nest material and sometimes killing trees outright by the accumulation of guano.
Little Blue Herons forage by wading up to their bellies in freshwater, brackish, or saltwater wetlands, with their necks extended stiffly forward and bills tilted down, occasionally swaying the head and neck as they size up their prey. Little Blue Herons often forage with other species, and they are gregarious breeders, nesting in multispecies colonies alongside ibises, Brown Pelicans, Tricolored Herons, and other waterbirds. They may chase and attack other members of their own species in defense of food or nesting territory, striking and jabbing at each other with their bills. Little Blue Herons fly with slow, steady wingbeats, usually with neck and head pulled back against the body. A courting male points his bill straight upward, suddenly extending and retracting his neck. Little Blue Herons of both sexes, when courting, may occasionally grasp, pull, and shake branches while simultaneously erecting the feathers along their head, neck, and back. Nestling Little Blue Herons, along with many other waterfowl, compete fiercely for the food their parents bring back. In lean years, the older chicks may attack and sometimes kill their younger, smaller nestmates to claim the food for themselves—a behavior known as siblicide.
Little Blue Heron populations declined by 55% between 1966 and 2015, according to the North American Breeding Bird Survey. The species rates a 14 out of 20 on the Continental Concern Score. Little Blue Heron is on the 2016 State of North America's Birds' Watch List, which includes bird species that are most at risk of extinction without significant conservation actions to reverse declines and reduce threats. The North American Waterbird Conservation Plan lists Little Blue Herons a species of High Concern. Habitat loss and human-caused changes in local water dynamics pose the most serious threats to regional populations. The Migratory Bird Treaty Act as well as state wildlife laws protect herons from harassment, killing, or collecting. However, Little Blue Herons that forage at fish hatcheries are vulnerable to illegal shooting; and the U.S. Fish and Wildlife Service and some states issue permits to legally shoot them. Like all waterbirds, Little Blue Herons are vulnerable to changes in water quality. Birds that eat prey from flooded agricultural fields and drainage ditches risk contamination by pesticides and heavy metals. Human disturbance has also been shown to harm colonial breeding bird populations, causing adults to abandon nests, eggs and chicks to die, and other impacts. Closing wading-bird colonies to human disturbance during the breeding season can help protect Little Blue Herons.
- Rodgers, Jr., James A. and Henry T. Smith. 2012. Little Blue Heron (Egretta caerulea). In The Birds of North America Online, No. 145 (A. Poole, Ed.). Cornell Lab of Ornithology, Ithaca, New York.
- Ehrlich, P. R., D. S. Dobkin, and D. Wheye. 1988. The Birder’s Handbook. Simon & Schuster Inc., New York.
- Kushlan, J.A., et al. 2002. Waterbird conservation for the Americas: the North American Waterbird Conservation Plan, version 1. Waterbird Conservation for the Americas. Washington, DC.
- North American Bird Conservation Initiative. 2016. The State of North
America’s Birds 2016. Environment and Climate Change Canada: Ottawa, Ontario.
- USGS Patuxent Wildlife Research Center. 2015. Longevity records of North American Birds.
- USGS Patuxent Wildlife Research Center. 2015. North American Breeding Bird Survey 1966–2015 Analysis
Resident to medium-distance migrant. Birds that breed in the interior Southeast migrate to Central and South America and the Caribbean; individuals along the Gulf Coast, Florida, and elsewhere disperse only short distances.
Find This Bird
Scan the edges of shallow water, particularly where there is adjacent emergent vegetation or overhanging bushes or trees, for this fairly inconspicuous heron. You’ll typically see them only in ones and twos, although they may gather with other herons and egrets, particularly at times when a school of small fish has become trapped in shallow water. In open, marshy habitats you may also see Little Blue Herons flapping slowly on rounded wings across the sky. Little Blue Herons often nest with other waterbirds, so if you can find an active colony, scan through the incoming and outgoing birds for small herons with completely dark plumage.