Theristicus
Theristicus is a genus of birds in the family Threskiornithidae. They are found in open, grassy habitats in South America. All have a long, decurved dark bill, relatively short reddish legs that do not extend beyond the tail in flight, and at least the back is grey.
Taxonomy
The genus Theristicus was erected by the German naturalist Johann Georg Wagler in 1832 with the black-faced ibis as the type species. The name is from the Ancient Greek theristikos meaning "of reaping".Formerly, T. caudatus included T. melanopis as a subspecies, but today all major authorities accept the split.
| Image | Scientific name | Common Name | Distribution |
| Theristicus caerulescens | Plumbeous ibis | south-western Brazil, especially in southern Mato Grosso and Rio Grande do Sul; Paraguay, especially in the Chaco and in the Paraguayan section of the Parana Basin; Uruguay; north-eastern Argentina and northern and eastern Bolivia | |
| Theristicus caudatus | Buff-necked ibis | northern and central South America in Colombia, Venezuela, the Guianas and Brazil | |
| Theristicus melanopis | Black-faced ibis | central Argentina and Chile | |
| Theristicus branickii | Andean ibis | western South America |