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
Green Ibis
Mesembrinibis cayennensis
The green ibis is a medium-sized ibis, with short legs and a long, slender, decurved bill. It measures 45–60 cm (18–24 in) in length and ranges from 700 to 890 g (1.5 to 2.0 lb) in mass. The sexes, which are identical in plumage, overlap somewhat in measurements, though the largest birds are male. Breeding adults have glossy greenish-black bodies, pale green legs and bill, and grey bare facial skin patches. Juveniles are much duller, but can be distinguished from the similar glossy ibis by their bulkier shape, shorter legs and broader wings.
ID text from Wikipedia, CC BY-SA 4.0
Where you might meet both
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