The White-faced Ibis is one of three members of Plegadis in the New World. It is very closely related to and very similar in appearance to the Glossy Ibis (Plegadis falcinellus). The White-faced Ibis is distributed widely in the Americas, although in North America it is primarily a species of the west side of the continent. In South America it occurs throughout the continent, although it is much less common in Chile than in adjacent Argentina. In breeding plumage the main distinguishing features of this species are the reddish eyes, pink facial skin and the broad white trim of feathering around the face; and reddish legs with brighter red “knees.” It is thought that the Glossy Ibis may be a relatively recent immigrant to the New World, having arrived from Africa or Europe; as the Glossy Ibis has spread sympatry has increased between these two closely related species and presumed hybrids have occurred throughout the central and western United States and Mexico. There have been no studies to understand the dynamics of sympatry in these two species, in particular if assortative mating is occurring for the most part, and what the viability of these hybrids is.