A glossy ibis seen foraging on a mud flat.
A glossy ibis seen foraging on a mud flat.
Courtesy: E. Marks, Audubon Society of Rhode Island

Glossy Ibis (Plegadis falcinellus)

Field markings: 23 inches long, with a wingspan of 36 inches. Dark, copper-colored wading bird with a long, down-curved bill and long, gray brown legs.
Habitat: Brackish and saltwater marshes, estuaries, coastal islands, and fields.
Seasonal appearance: Spring, summer, early fall.

Description

Glossy ibis are wading birds common to the marshes of Rhode Island. They appear dark at a distance, however, adults are chestnut colored with an iridescent purple gloss on the head, neck, and underside. During the nonbreeding season, the facial skin is gray, while in the breeding season, it becomes a cobalt blue, with the leg joints turning red on green gray legs. Immature birds are a dark green with brownish heads, and their necks are covered with streaks. Unlike great blue heron and other wading birds, glossy ibis fly with their necks extended.

Life History and Behavior

Glossy ibis nest in small mixed colonies with other wading birds, such as great egrets and black-crowned night herons, on islands in Narragansett Bay. Nests are built of sticks and twigs in trees or shrubs up to 10 feet from the ground. A lining of dry material is maintained until the young leave. The female lays three to four eggs, and both parents incubate for 21 days. The female usually incubates the nest at night and the male incubates during the day. After about seven weeks, the young leave the nest and forage with the parents.

Glossy ibis forage mainly in freshwater and saltwater marshes, particularly on Conanicut and Aquidneck Islands in Rhode Island. They wade through the shallows probing the mud with their long down-curved bills for crabs, crayfish, worms, and other aquatic invertebrates. Glossy ibis feed commensally with other wading birds, such as the snowy egret. Since the glossy ibis forages by feel, it stirs up food in the murky waters for the snowy egret, which forages by sight. The glossy ibis may gain the advantage of having an extra lookout for any predators.

Special Designation The Rhode Island Natural Heritage Program currently lists the glossy ibis as a species of special concern in the state.

Special Notes


Adapted from The Uncommon Guide to Common Life on Narragansett Bay. Save The Bay, 1998.