cuapetlahuac.

CUA-PETLA-HUAC, Wood Stork (Mycteria americana) [FC: 32 Quapetlaoac] “It is a bald-head –big, tall, the same as the [Great Blue Heron, axoquen]. Its head is large…. Featherless, bald, bare to the back of its head. The sides of its head are chili-red, reaching to its neck [?]. It is long-necked. Its bill is very thick as well as cylindrical, long, like a bow. Its breast is black. Its back, its wings are completely ashen, except that the wing-bends are very black. It tail is short, black. This quapetlaoac slod comes when [water] birds come. It is quite rare.” Martin del Campo identified this bird as the “wood ibis,” now known as the Wood Stork. The description fits very well, except for the red “sides of the head,” which could be due to confusion with the Wood Stork’s close relative, the Jabiru (Jabiru mycteria).
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analysis here also appearing in E. S. Hunn, "The Aztec Fascination with Birds: Deciphering Sixteenth-Century Sources," unpublished manuscript, 2022, cited here with permission.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 wood ibis
Henry M. Reeves, "Once Upon a Time in American Ornithology," The Wilson Journal of Ornithology 119:2 (June 2007), 317.