See an image that represents cozcacuauhtli in the Visual Lexicon of Aztec Hieroglyphs, ed. Stephanie Wood (Eugene, Ore.: Wired Humanities, 2020-present).
COZCA-CUĀUH-TLI, literally, “necklace/yellow eagle/hawk,” Crested Caracara (Caracara cheriway) [FC: 42 Cozcaquauhtli] “It is smoky. The wings are curved, resembling an eagle’s. The bill is curved.” Martin del Campo identified this bird as the King Vulture (Sarcoramphus papa). However, I can see no reason for that conclusion based either on the name or the Codex description. The attributive would mean “necklace/jewel/ornament” if the vowel “o” were long; yellow if short. A more likely interpretation is that the bird in question is the Crested Caracara (Caracara cheriway), as it is said to resemble the Laughing Falcon, see HUAC-TLI.
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analysis here also appearing in E. S. Hunn, "The Aztec Fascination with Birds: Deciphering Sixteenth-Century Sources," unpublished manuscript, 2022, cited here with permission.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 name glyph for the cozcacuauhtli in the Codex Quetzalecatzin shows a red protrusion above the beak and spiky feathers on its head.