Little Blue Heron, Egretta caerulea

Little Blue Heron, Egretta caerulea, Immature. Photograph taken within the San José del Cabo Estuary, San José del Cabo, Baja California Sur, March 2017.  Photograph courtesy of Carol Snow, Del Mar, California.

Little Blue Heron, Egretta caerulea, Immature. Photograph taken along the rocky shoreline of the greater Bahía de los Ángeles area, Baja California, February 2022. Photograph courtesy of George Flicker, Bahía de los Ángeles. Identification courtesy of Mary & George Flicker, Bahía de los Ángeles.

Little Blue Heron, Egrettta caerulea, Adult. Photographs taken in the wild in the Los Cabos area of Baja California Sur, December 2019. Photographs courtesy of Dr. Tom Bartol, Carlsbad, California.

Little Blue Heron, Egrettta caerulea, Adult. Photograph taken in the coastal area of Yavaros, Sonora, November 2017. Photograph and identification courtesy of David F Smith, Alamos, Sonora.

Background and Identification

The Little Blue Heron, Egretta caerulea, is a member of the Ardeidae Family of Herons, Egrets and Bitterns. There are twelve members of the Egretta Genus. They are known in Mexico as garceta azul and garza azul. They are unique among the herons in exhibiting distinct color morphs for first-year immature (white) and adult (slate-blue) plumages.

The Little Blue Heron is a mid-sized heron. The sexes are similar in appearance and the plumages are maintained year-round. Adults are mostly slate-blue on body and wings, with a purplish head and neck, and black-tipped bill. They lack the filamentous aigrette plumes found in other herons. They have long, lanceolate plumes on the crest and back during breeding season. Their bill is bicolored with a bluish base, their iris in grayish green in adults and yellowish to white in immature birds, their legs are gray to grayish-green in adults and yellow to pale gray in immatures.

Habitat and Geographical Range

The Little Blue Heron are normally found year-round within coastal wetlands, saltmarshes, tidal flats, exposed reefs, beaches and mangrove swamps at elevations up to 1700 m (5,600 feet). They are secretive in nature and the adults are often overlooked in wetland environments due to their dark plumages. They are diurnal feeders that feed as solitary individuals or in small groups with other species of colonial waterbirds in various freshwater and marine-estuarine wetland habitats. They consume a variety of small fish, small amphibians, and invertebrates, particularly crustaceans. They are famous for their “slow-walk” hunting technique. Their nests are preyed upon by birds, small mammals, and snakes. They nest in mixed-species assemblages of colonial waterbirds using varied colony habitat and nesting substrate. They roost in mixed species. They have life spans of up to fourteen years.

In Mexico the Little Blue Heron is found within all coastal regions of both the Atlantic and Pacific Coasts during the winter months. They are a partial migrator with some wintering shore birds moving north in the spring to the United States and returning late fall. Wintering birds can be found in Baja California, Baja California Sur, along both the Atlantic and Pacific coasts. Others are non-migratory year-round residents found in central Mexico from southern Zacatecas south to Guatemala.

Common Misidentifications

The adult Little Blue Heron are most likely confused with the Reddish Egret, Egretta rufescens (pinkish bill). The juveniles are often confused or misidentified with other white herons including the Snowy Egret, Egretta thula (uniform colored bill, yellow loral skin).

Conservation Status

From a conservation perspective the Little Blue Heron is currently considered to be of Least Concern with stable, widely distributed populations.