acuicuialotl.

Ā-CUICUIALO-TL, Variant of Ā-CUICUIYALO-TL, Cliff Swallow (Petrochelidon pyrrhonota) [FC: 28 Acujcujalotl]: “It nests in the crags and house roofs, house fronts. It is a mud nest builder which plasters with its bill. Its nest is of tattered cloths. It is [dark] ashen, like a cujcujtzcatic {Barn Swallow).” As this contrasts with the Barn Swallow (CUĪCUĪTZCA-TL), it must be the other mud-nesting swallow common in the Valley of Mexico, the Cliff Swallow.
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analysis here also appearing in E. S. Hunn, "The Aztec Fascination with Birds: Deciphering Sixteenth-Century Sources," unpublished manuscript, 2022, cited here with permission.