yauhtichuitzilin.

YAUHTIC HUĪTZIL-IN, literally, "dark hummingbird," species of hummingbird (Trochilidae) [FC: 24 Yiauhtic vitzili] “… is dark green.” This might refer to any number of Central Mexican hummingbird species, so an educated guess is unwarranted. See also HUĪTZIL-IN.
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); 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analysis here also appearing in E. S. Hunn, "The Aztec Fascination with Birds: Deciphering Sixteenth-Century Sources," unpublished manuscript, 2022, cited here with permission.