Bird Observer - The New England Birding Journal

Bird Observer

The Birding Journal for New England

August 2018

Vol. 46, No. 4

Front Cover: August 2018

Tricolored Heron by Ikki Matsumoto

Born in Tokyo, Japan, internationally-acclaimed artist Ikki Matsumoto (1935–2013) came to the United States in 1955 to study art first at the Herron School of Art and Design in Indianapolis, Indiana, and then at the Art Academy of Cincinnati, Ohio, under wildlife artist Charles Harper. Ikki worked in advertising, illustration, and design until 1975. One of his commissions was to illustrate the 1975 edition of Joy of Cooking.

Ikki embarked on a new career as a printmaker and painter, using native birds as his subjects, when he and his wife Polly moved to Sanibel Island, Florida, in 1975. For many years, they ran an art gallery in Sanibel. After retiring from the gallery business in 2006, Ikki continued to paint and exhibit his work. He died on December 31, 2013, one day before his 79th birthday. For more information, go to: www.ikkimatsumoto.com

Tricolored Heron

The Tricolored Heron (Egretta tricolor), a common coastal resident of our southern states but only a casual visitor to New England, is one of the best studied and most interesting of the herons. A medium-sized heron, it has dark blue upperparts tinged with maroon and white underparts in all plumages from juvenile to adult of both sexes. The mostly blue neck and head is offset with white and reddish highlights below. The contrasting color patterns separate the Tricolored Heron from all other heron species. In breeding plumage, both sexes sport white cranial plumes, white throats, and red to violet neck and back feathers with buff-colored scapular plumes. The legs become pink and the base of the bill bright blue—pretty spectacular. Two subspecies are currently recognized with E. t. ruficollis the resident United States subspecies.

Tricolored Herons breed along the East Coast from Long Island south through Florida, along the Gulf Coast to northern Mexico, and in the Caribbean. They also breed along the Pacific Coast from northwestern Mexico south through Central America and in South America along the coast to northeastern Brazil and southern Peru. Tricolored Herons in the Northeast are migratory as, apparently, are the birds of northern Florida, wintering from central Mexico south to Panama. Most populations are year-round residents. In Massachusetts, the Tricolored Heron is considered a rare breeder and an uncommon visitor and migrant. In the mid-1970s, four pairs nested and fledged young in Manchester, but the species has not become a regular breeder. The first reported sighting was in 1940, and since the mid-1950s sightings have been reported nearly annually from April to September, mostly along the coast, but occasionally also from the Connecticut Valley.

Tricolored Herons are monogamous and usually produce a single brood per season. Male Tricolored Herons have several courtship displays. In the snap-stretch display, when the female approaches, the male erects all plumes as he holds out his wings, lowers his head, picks up a twig and then points the bill and neck upward while swaying, accenting the cobalt-colored skin around his eyes and his white throat. In the circle flight, he holds his bill upward and with deep wingbeats produces a whomp-whomp sound. Aggressive displays include an upright stance with feathers sleeked back and the bill pointed upward or held horizontal. Another aggressive stance includes extending the neck upwards, with feathers of the neck and head crest erected, and wings drooped. Males aggressively defend the vicinity of their nest and sometimes their feeding sites. They give aaah calls in aggressive situations. At the nest, both sexes greet each other with cuhl-cuhl sounds during nest relief, which may aid in individual recognition.

Tricolored Herons prefer coastal habitat such as mangroves, salt marshes, and estuaries, but also occur in freshwater environments such as the Florida Everglades. They prefer to nest on islands where they gain some protection from mammalian predators. They typically nest in mixed-species colonies, but more often within small groups of their own species. The male choses the territory and nest site, usually in tall shrubs or small trees up to about 12 feet above the water. Before pairing, the male builds the nest, a loose platform of sticks and twigs. After pairing, both sexes share in finishing the nest with a lining of fine twigs and grass. The male closely guards the territory, nest, and female through the egg-laying stage. The usual clutch of three or four greenish blue eggs are incubated by both parents for about three weeks until hatching. The chicks are semi-altricial: nearly covered with down, their eyes partly open, and the ability to hold their heads up and peep. By day 11 they can leave the nest, climbing about using their wings, bills, and feet. When they are two weeks old, they can regulate their own body temperature and need no further brooding. They can fly by one month of age. Both parents feed the young, initially by regurgitation of well-digested food, but within a week they bring the chicks small, undigested fish. The young are independent at 7–8 weeks.

Tricolored Herons usually forage alone or at the edge of mixed-species flocks. They forage mostly in wetlands, usually in more open areas. They are versatile foragers and use several techniques: stand-and-wait, walk slowly, walk quickly, and run. They often use foot stirring to chase up prey. In disturb-and-chase manoeuvers, they typically crouch low, neck tucked into the breast feathers, and lunge for any fish they've disturbed. Chasing fish in active pursuit, they may flap their wings or pirouette with an open wing. Or they may form a tent over head and body with extended open wings. They may also strike at fish while they hover over the water surface. More than 90% of their diet is composed of fish but they will occasionally exploit other abundant food resources such as grasshoppers, frogs, or lizards. This versatility in foraging behavior and prey allows Tricolored Herons to exploit a wide variety of habitats.

Tricolored Herons have many predators. Crows, grackles, blackbirds, and night-herons are egg predators; hawks, eagles, and vultures prey on young. Raccoons are especially keen nest predators. During nesting, rain and wind can also cause mortality. Historically, Tricolored Herons were not heavily affected by plume hunters and for much of the first half of the twentieth century were the most abundant North American heron species. They expanded their range and population numbers during the 1950s–1980s, possibly due to the construction of man-made dredge spoil islands, which they readily used for breeding. Populations have since declined, due partly to the proliferation of fish farms and resulting permits issued to kill intruding herons, and partly to coastal habitat degradation. However, Tricolored Herons are widespread geographically and are versatile foragers, which with luck will ensure them a stable future.

William E. Davis, Jr.

blog comments powered by Disqus