xalcuani.

XĀLQUANI, literally, "eats sand," American Wigeon (Mareca americana) [FC: 36 Xalquani] “It is named xalquani because it always eats sand, though sometimes it eats… [water plants]. It is the size of the goose. [On] its head, its feathers are white on the crown; the sides of its head green, resplendent…. It does not rear its young here; it also migrates.” I agree with Martin del Campo that this must be the American Wigeon (known then as “Baldpate”), based on the plumage characteristics noted, despite the fact that it does not “eat sand,” nor is it “the size of a goose.” See also CANAUH-TLI “duck.”
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analysis here also appearing in E. S. Hunn, "The Aztec Fascination with Birds: Deciphering Sixteenth-Century Sources," unpublished manuscript, 2022, cited here with permission.

The Florentine Codex includes a painting of this bird in Book 11, folio 37v.
Available at Digital Florentine Codex/Códice Florentino Digital, edited by Kim N. Richter and Alicia Maria Houtrouw, "Book 11: Earthly Things", fol. 37v, Getty Research Institute, 2023. https://florentinecodex.getty.edu/en/book/11/folio/37v/images/0 Accessed 17 October 2025.