White-faced Ibis

The White-faced Ibis (Plegadis chihi) is a medium-sized wading bird of the family Threskiornithidae, closely related to and formerly considered conspecific with the Glossy Ibis (Plegadis falcinellus). Breeding adults are distinguished from the Glossy Ibis by a band of white feathers bordering the bare reddish facial skin around the eye and bill base, and by reddish (not grayish-blue) legs. In non-breeding and juvenile plumages the two species are extremely similar, with the White-faced Ibis showing warmer reddish-brown tones and red rather than gray eyes. Body length is 46–66 cm and wingspan 91–105 cm.

The White-faced Ibis breeds primarily in freshwater marshes of the interior western North America, from the Great Basin region of the United States south through Mexico and into South America as far as Chile and Argentina. In North America, major breeding colonies are located in Utah, Nevada, Oregon, and the Gulf Coast of Louisiana and Texas. The species winters largely along the Gulf Coast and in Central America and South America. It is strongly migratory across its northern range.

Freshwater marshes with dense emergent vegetation such as bulrush and cattail are the preferred breeding and foraging habitat. During migration and winter, the bird also uses flooded agricultural fields, rice paddies, shallow lake margins, and coastal wetlands. The White-faced Ibis forages by wading in shallow water and probing the substrate with its long decurved bill, detecting crayfish, earthworms, insects, small fish, frogs, and other invertebrates by touch. It often feeds alongside other wading birds in flocks.

Colonial breeding takes place in dense marsh vegetation, with nests built over water in bulrushes, willows, or low shrubs. Clutches typically contain three to four pale blue-green eggs, incubated by both parents for 17–26 days. Chicks fledge at approximately six weeks. Population declines occurred during the twentieth century due to habitat loss, pesticide contamination particularly from organochlorines that caused eggshell thinning, and colony disturbance. Following protection and the phaseout of DDT, populations recovered substantially and the species is now considered Least Concern.