Breeding Bird Atlas 1 Species Accounts
Little Blue Heron
Number of Broods
Little Blue Herons begin to arrive in Massachusetts in early April, when they can be observed foraging in coastal marshes, flooded grasslands, and freshwater ponds. The Little Blue Heron uses a wide variety of foraging behaviors, sometimes running actively, but more often walking slowly through shallow water or standing and peering straight down into the water. They often rake the bottom substrate with their feet, presumably to startle hidden prey. Sometimes they also capture prey flushed by other birds or animals. The diet of the Little Blue Heron is diverse, consisting of fish, frogs, insects, and other small animals.
In Massachusetts, Little Blue Herons typically begin nesting in early May. They are colonial breeders, sharing heronries with the much more common Snowy Egret. At Clark’s Island they have nested in Highbush Blueberry, Red Cedar, and probably Black Cherry. Breeding activities are highly ritualized. Males defend a territory around the nest and advertise primarily by an elaborate “stretch display” (Palmer 1962), bending the head backward and moving the body up and down in a pumping motion. Aggressive displays include the “upright display” with slightly erected crest and the “forward display” (Palmer 1962) with the feathers of the head, neck, and back raised. Harsh aarh calls accompany hostile interactions. The members of a pair have an elaborate series of calls and greeting ceremonies at the nest.
The nest, constructed of small sticks and twigs, is a loosely woven platform less than 3 feet in diameter. Males gather most of the nest materials and pass them to the females, which weave them into the nest. The eggs are a light bluish green, usually three to five in number. The three-week incubation period, shared by both parents, begins with the second egg. Hatching is asynchronous, resulting in a brood of chicks of varying size. Initially, food is regurgitated into the nest by the parent, but after about 5 days the young are fed directly from the adult’s bill. Juveniles clamber about the nest tree after about two weeks and can fly at a month old. They continue to be fed by the adults until they are six or seven weeks old.
Little Blue Herons have a pronounced postbreeding dispersal, during which time they are sometimes observed at inland sites. They migrate south in September and winter from the southern United States to South America.