Glossy Ibis

Plegadis falcinellus

(c) Howard B. Eskin
  • THRESKIORNITHIDAE
  • Ibises, Spoonbills
  • Ciconiiformes
  • Ibis cara oscura
  • Ibis falcinelle
Introduction
A relative newcomer to North America, the Glossy Ibis first expanded its range along the Atlantic Coast in the early 19th century. Today, the scarlet and iridescent green of its breeding plumage can be observed on every continent except Antarctica. Like other ibis, this lightweight, large-footed relative of the spoonbills has a sickle-shaped bill to feel for prey. The Glossy Ibis is a wetland generalist.
Appearance Description
Glossy Ibis weigh about 1.2 pounds and measure 23 inches, with a 36-inch wingspan. Once called the “Black Curlew,” the Glossy Ibis is a medium-sized, dark wading bird with a long, decurved bill. During breeding, this ibis is chestnut to maroon in color, with dark green, glossy wings, back, and tail. The bill is dull brown, while the legs and feet are dark red. Two fine, pale gray lines connect the face to the bill. In winter, the Glossy Ibis is darker and less reddish. Its eyes are usually black. Both sexes of the Glossy Ibis appear similar. This species is easily confused with the White-faced Ibis, which exhibits subtle differences including red eyes, bright white facial lines during breeding, and lighter upper-parts.
Range Map
Courtesy Kenn Kaufman
Range Distribution
After a large range expansion northward from the 1930s through the 1970s, the Glossy Ibis breeds irregularly along the Atlantic Coast from southern Maine to Florida, across the Florida peninsula, and along the Gulf Coast into Texas. Breeding colonies are most concentrated in Florida and southwestern Louisiana. This ibis winters largely from the Carolinas south through Florida and just into Texas. Significant numbers also breed and winter through the Caribbean and most of Central America. The Glossy Ibis also occurs in southeastern Europe, most of Africa south of the Sahara, the Near East, Southeast Asia, and most of Australia east of the outback.
 
A legend for the range map to the right can be found here.
Habitat
During breeding season, the Glossy Ibis usually inhabits wooded wetlands close to the coast. Foraging birds wade in moist to submerged marshes, lagoons, and mudflats. This ibis is also found on flooded and dry fields, sewage ponds, and estuaries. Its wintering habitat appears to be similar.
Feeding
Often feeding in small, close flocks, the Glossy Ibis walks slowly through marshes, feeling for prey with its long, curved bill by probing into mud and submerged vegetation. This dark ibis may also hold its bill open in shallow water, swing its bill through water, and peck items from various surfaces. The bird’s omnivorous diet includes water beetles, dragonflies, flies, earth and marine worms, leeches, mussels, clams, frogs, small snakes, small fish, and various seeds. Glossy Ibis often associate with other wading birds; some herons, like the Snowy Egret, appear to find prey disturbed by the ibis.
Reproduction
In North America, the breeding biology of the Glossy Ibis has not been fully studied. Glossy Ibis probably form monogamous pairs for the breeding season, and maintain bonds with mutual preening, bowing, and bill touching. Both sexes build a tight, bulky, bowl-shaped, unlined nest in a tree, shrub, or dense ground vegetation, and add material, including twigs, reeds, rushes, and course grasses, until the chicks hatch. The female lays three to four greenish-blue to dark blue eggs, which both sexes incubate for about three weeks.
 

The fairly helpless chicks are cared for by both sexes and are fed regurgitated food from their parents’ open bills. Different hatching times create a hierarchy based on size among the young; in clutches with four hatchlings, the smallest ibis rarely survives. Within two to three weeks, the young climb into surrounding branches, returning to the nest only for feeding. Young Glossy Ibis fledge in about four weeks, accompany their parents to foraging sites after about six weeks, and are independent in less than two months.

Migration

Migrating day or night in small flocks, often in V-shaped formations, Glossy Ibis arrive in late March through April along the Atlantic coast north of the Carolinas. After breeding, this ibis is well known for dispersing far and wide across the continent, a habit that probably led to its colonization of the Americas. Fall migrants begin to disperse in mid-July and move through America’s southern coasts and the Caribbean. A few linger in the Carolinas and Florida.

CBC Graph
Graph Legend
Annual Population Indices
  • 2,200,000
  • 21,000
Population Status Trends
During the Glossy Ibis’ great range expansion, its population also grew significantly. From a few breeding pairs in Florida in the late 1920s, by 1975, an estimated 13,500 Glossy Ibis were breeding along the Atlantic Coast. Since then, surveys have recorded dramatic fluctuations in breeding colonies, even from year to year, for unknown reasons. For example, New Jersey’s Coastal Colonial Waterbird Survey noted about 3,000 Glossy Ibis in 1957, 3,799 in 1978, and 1,389 birds in 1995. Breeding and wintering surveys indicate stable or slightly increasing populations across North America, but chronic losses have prompted the listing of this dark ibis as a “species of conservation concern” in Delaware and Virginia; “imperiled” in Georgia and Louisiana; and a “species of greatest conservation need” in New York.
 
An explanation of the Annual Indices graph displayed to the right can be found here.
Conservation Issues
In North America, the recent appearance and sudden success of the Glossy Ibis has made it a low concern for conservationists, even in regions like Florida that have seen significant declines since the 1970s. Habitat loss through the draining of wetlands accounts for most losses in Florida, Massachusetts, and New York. Along the Atlantic Coast, oil spills and pollutants like DDT have had temporary but significant effects on the Glossy Ibis. The continued success of the Glossy Ibis depends on the security of coastal wetlands, including wooded and shrubby islands for nesting and roosting, and grassy marshes and shallow freshwater for foraging.
 
Federal efforts like the North American Colonial Waterbird Conservation Plan have adopted a global approach to species management. While the Glossy Ibis has experienced a wide range expansion, it has declined, sometimes perilously, in the Americas, Europe, North Africa, the Black Sea region, and the Ukraine. North America’s Glossy Ibis could become an important resource, if other populations continue to fail.
What You Can Do
Look for the Glossy Ibis from spring to fall in grassy marshes and freshwater lagoons. Join a nature walk at refuges such as the Jamaica Bay Wildlife Refuge Visitor Center in Queens, New York.
 
Attend a wildlife festival where Glossy Ibis may be seen, such as the Space Coast Birding & Wildlife Festival (January of each year) in Titusville, Florida.
 
Go online to monitor state and federal designations of waterbirds as “endangered,” “threatened,” or “species of special concern.” Most states provide listings and management plans for birds and critical wetlands. Visit the Pennsylvania Game Commission’s site for one such example.
 
For other actions you can take, including Audubon activities, please visit our resources page.
More Information
Visit our resources page for more information about this species.
Natural History References
Davis, W. E., Jr., and J. Kricher. 2000. Glossy Ibis (Plegadis falcinellus). In The Birds of North America, No. 545 (A. Poole and F. Gill, Eds.). The Birds of North America, Inc., Philadelphia, PA.
 
Kaufman, Kenn. Lives of North American Birds. Houghton Mifflin Company, New York, 1996.
 
Sibley, David Allen. The Sibley Guide to Birds. Alfred A. Knopf, New York. 2000.
Conservation Status References
Davis, W. E., Jr., and J. Kricher. 2000. Glossy Ibis (Plegadis falcinellus). In The Birds of North America, No. 545 (A. Poole and F. Gill, Eds.). The Birds of North America, Inc., Philadelphia, PA.
 
Kushlan, James A., et al. 2002. Waterbird Conservation for the Americas : The North
American Waterbird Conservation Plan, Version 1. Waterbird Conservation for the Americas, Washington, DC. 78 pp.
 
Sauer, J. R., J. E. Hines, and J. Fallon. 2005. The North American Breeding Bird Survey, Results and Analysis 1966 - 2005. Version 6.2.2006. USGS Patuxent Wildlife Research Center, Laurel, MD.
 

Sibley, David Allen. The Sibley Guide to BirdsNew York. 2000.. Alfred A. Knopf,