Black-faced Ibis
Theristicus melanopis
It has a total length of approximately 75 centimetres (30 in). The head, neck and lower chest are buffish, the crown and nape are cinnamon, the upperparts and (often incomplete) chest-band are grey, the belly and flight feathers are black, and the wing-coverts are whitish (though not contrasting strongly with the grey upperparts). The bill, throat-wattle and bare skin around the eyes are blackish and the legs are red.
ID text from Wikipedia, CC BY-SA 4.0
Buff-necked Ibis
Theristicus caudatus
It has a total length of approximately 75 centimetres (30 in). The neck is buffish, the upperparts are grey, the belly and flight feathers are black, and there is a large white patch in the wings. In flight, where the relatively short legs do not extend beyond the tail (unlike e.g. Eudocimus and Plegadis), the white patch forms a broad white band on the upperwing that separates the black remiges and the grey lesser wing-coverts. The bill and bare skin around the eyes are blackish and the legs are red.
ID text from Wikipedia, CC BY-SA 4.0
Where you might meet both
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