Introduction of the Great-Tailed Grackle by Aztec Emperor Auitzotl: Four-Stage Analysis with New Information

Abstract

The introduction of the great-tailed grackle Quiscalus mexicanus into the Valley of Mexico by Aztec Emperor Auitzotl during the years 1486–1502, is the earliest documented case of exotic bird introduction in the western hemisphere. This translocation was intensively managed and involved at least three different human interventions: (1) capture and transport of grackles to the Aztec capital, followed by release there, (2) supplemental feeding and (3) protection from human harassment and predation. Here I present new details of this ancient translocation gleaned from extant sixteenth-century manuscripts, and review what is known about each of the four stages of the introduction. The grackles were brought from more than one locality north of the Río de la Antigua (Gulf Coast region). After release at Tenochtitlan and Tlatelolco, they multiplied and dispersed. By 1577, they had spread more than 20 leagues, invading even areas between the Aztec capital and their native range. Complete protection of the introduced grackles ended relatively soon, either during the rule of Auitzotl or that of his successor Montezuma II (1502–1520). A related account of Aztec translocation of exotic plants can be used as a model to predict additional details of Auitzotl's introduction of the great-tailed grackle. Like the Auitzotl account, the plant account shows that a method and ideal of Royal Aztec translocation was to prevent the loss of each propagule. To achieve this goal, gardeners with experience cultivating the exotic plants in their native lands were imported from the Gulf Coast with them, and elaborate sacrificial rituals were performed. Large numbers of each exotic species were translocated, increasing propagule pressure and ensuring establishment.