New York Natural Heritage Program
Little Blue Heron
Egretta caerulea (Linnaeus, 1758)
Birds

Identifying Characteristics [-]
The little blue heron is a small to medium-sized heron; about 60 cm in length with a wingspan of about 100 cm. Adults are slate blue in color. Legs are dark green and bill is pale with a black tip. During the breeding season, the head and neck turn a deep reddish-brown (Peterson 1980; National Geographic Society 1999). The birds nest in colonies with other species of herons. Nests are platform in shape, about 40 cm wide and 25 cm deep, and are constructed from dead twigs and sticks and lined with vegetation. They are formed in trees or shrubs 1-4 m from the ground. Four to five eggs are typically laid. The eggs are oval in shape, have a smooth shell, and are pale blue-green in color. The average size of the eggs is 44 mm x 44 mm (Bent 1926). Young are born pure white and resemble snowy egrets. They remain white typically until their first spring and gradually change over to blue (Peterson 1980; National Geographic Society 1999). The sub-adults with both white and blue plumage are often classified as calico or piebald (Rodgers and Smith 1995). Little blue herons have several different types of vocalizations. Nestlings and fledglings emit a food begging call that sounds like "hee-hee-hee". Typical adult vocalizations include those made breeding/greeting, that sounds like "Unh" and "Eh-oo-ah-eh-eh". When the birds are disturbed or show aggression, they make a "Sken" sound. They also produce nonvocal sounds such as bill nibbling which sounds like a rattle during courtship and bill snapping while exhibiting a stretch display (Rodgers and Smith 1995).

Characters Most Useful for Identification [-]
The slate blue plumage and reddish-brown neck of the adults during breeding season are the most useful characteristics for identifying little blue herons.

Best Life Stage for Proper Identification [-]
Adults in breeding plumage are the best stage for identifying this species

Behavior [-]
Little blue herons arrive at their breeding grounds in early spring, and courtship, which is initiated by the males, begins soon after. Male birds walk throughout the colony, strutting, stretching, and snapping their bills. They establish their core territory which eventually becomes the nest site. Little Blue Herons are colonial nesters and often nest with other species of herons. Both the male and female aid in nest building, with the male gathering nest materials and the female doing most of the construction. Eggs are laid soon after the nest is constructed. The incubation period lasts around 22 days, with the male and female taking turns incubating. Hatching is asynchronous and occasionally results in mortality of younger chicks. The Little Blue Heron forages during the day in shallow water by wading very slowly and peering into the water, with the bill close to the surface. When prey is spotted, the head often sways in a semi-circle around the bill at the point of contact with the water just before striking (Willard 1977; Rodgers and Smith 1995).

Diet [-]
Little blue herons forage in coastal marshes and estuaries for various types of fish, crustaceans, and other small invertebrates. The birds feed on regional species including minnows, anchovies, killifish, and darters, to name a few (Bent 1926; Rodgers and Smith 1995).
Little Blue Heron Images
click to enlarge
The Best Time to See
Little blue herons can be found breeding on the non-barrier islands of Long Island from late May to August (Rodgers and Smith 1995).
J F M A M J J A S O N D
Present Breeding
The time of year you would expect to find Little Blue Heron present (blue shading) and breeding (orange shading) in New York.
Similar Species
  • Snowy Egret (Egretta thula)
    Young and immature Little Blue Herons are frequently confused with immature Snowy Egrets. The immature herons have a pale bill with a dark tip and dark feet while the egrets have a dark bill and yellow feet (National Geographic Society 1999).