The Buff-necked Ibis is one of the most widespread species of ibis in South America. It occurs in a wide variety of open habitats such as savanna, ranchland and open forest, but is notable for often being found far from water. It is one of the most distinctive large waders in South America having a bright buffy head and neck, grey back, white primaries and secondaries and black underparts. It is polytypic, with a northern paler subspecies and a southern subspecies that together with the Black-faced Ibis of the Andes form a superspecies. This superspecies has the greatest nest site diversity of any member of its family (Threskiornithidae) with solitary nests to large colonies, placed in a variety of locations such as tree stumps in swampy areas, reed mats, rocky outcrops, cliffs, gullies, or trees in patches of woodland.