elotototl.

ĒLŌ-TŌTŌ-TL, literally, “green corn bird,” Blue Grosbeak (Passerina caerulea) [FC: 22 Elutototl]: “Its wings and its bill are of dull colors. It is [the color of] the lovely cotinga {xiuhtototic} – light blue. It looks dull, it turns dull.” Martin del Campo identified this bird as the Blue Grosbeak. Of the several bluish birds that might fit this description, e.g., Blue Bunting (Cyanocompsa parellina), Indigo Bunting (Passerina cyanea), only the Blue Grosbeak is a permanent resident of the Central Mexican highlands, and thus perhaps the best option. The Blue Grosbeak has dark wings, brown wing-bars, and a gray bill, details that fit.
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analysis here also appearing in E. S. Hunn, "The Aztec Fascination with Birds: Deciphering Sixteenth-Century Sources," unpublished manuscript, 2022, cited here with permission.