chalchiuhtototl.

CHALCHIUH-TŌTŌ-TL, literally, “jade bird,” Red-legged Honeycreeper (Cyanerpes cyaneus) [FC: 21 Chalchiuhtototl] “It is a forest -dweller; small, pointed and small of bill. Its head and tail are herb-green, and its wings, on the outer surfaces, are also herb-green, somewhat dark green. And the under part of the wings and all its body are light blue, turquoise, very light blue, the color of fine turquoise….” The description appears to be an amalgam of the male and female plumages of the Red-legged Honeycreeper, listed by Martin del Campo as the Blue Honeycreeper, an earlier name for this species, but with reservations. The underwings of this honeycreeper are bright yellow, not blue, as described. However, this is nevertheless the most likely identification.
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analysis here also appearing in E. S. Hunn, "The Aztec Fascination with Birds: Deciphering Sixteenth-Century Sources," unpublished manuscript, 2022, cited here with permission.