zolcanauhtli.

ZŌL-CANAUH-TLI, literally, “quail duck,” Gadwall (Anas strepera) [FC: 37 Çolcanauhtli] “It is named çolcanauhtli (zolcanauhtli) because its feathers are all like quail feathers. It is rather large, the same size as a Peru [duck] [perhaps a domestic Mallard brought by the conquistadors]. White [feathers] are set only on the point of each wing-bend. The bill is small and wide; its legs black, wide, small. It is an eater of atatapalcatl [water plant] and achichilacachtli [gibbous duckweed]. It also comes, it also migrates with the others. Also it does not rear its young here. Many come here.” Martin del Campo identified this duck as the Mallard (Anas platyrhnchos). However, that species is rare south of northern Mexico (at least now) and does not fit the description in other ways. I suspect that the duck in question is the Gadwall (Anas strepera). Though it doesn’t match all the details, it does show distinctive white patches at the base of the wing, which might be what was intended by the “point of each wing-bend.” See also CANAUH-TLI.
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 11 – Earthly Things, no. 14, Part XII, eds. and transl. Arthur J. O. Anderson and Charles E. Dibble (Santa Fe and Salt Lake City: School of American Research and the University of Utah, 1963); Rafael Martín del Campo, “Ensayo de interpretación del Libro Undecimo de la Historia General de las Cosas de Nueva España de Fray Bernardino de Sahagún – 11 Las Aves (1),” Anales del Instituto de Biología Tomo XI, Núm. 1 (México, D.F., 1940); and, with quotation selections, synthesis, and analysis here also appearing in E. S. Hunn, "The Aztec Fascination with Birds: Deciphering Sixteenth-Century Sources," unpublished manuscript, 2022, cited here with permission.