Ancient DNA and spatial modeling reveal a pre-Inca trans-Andean parrot trade

Abstract

Vibrant feathers from Amazonian parrots were among the most prestigious symbols of status in the pre-Hispanic Andes, yet their acquisition required traversing the formidable Andean mountain range. Here, we investigate feathers recovered from an intact, elite masonry tomb at the coastal religious center of Pachacamac, associated with the pre-Inca Ychsma culture that flourished during the Late Intermediate Period (ca. 1000–1470 CE). By integrating ancient DNA, stable isotope analysis, and spatial modeling, we reconstruct the complete journey of these feathers. Genomic data identify four distinct Amazonian parrot species (Ara macao, A. ararauna, A. chloropterus, Amazona farinosa) and reveal high genetic diversity, indicating extraction from wild populations rather than local breeding. Stable carbon and nitrogen isotope analysis reveals that these birds consumed a C4-rich coastal diet, demonstrating they were transported alive across the Andes and kept in the arid coast. Finally, we identify specific trans-Andean corridors used for this exchange by combining species distribution models of ancient habitats with landscape resistance modeling. Our findings reveal a sophisticated, managed trade network operated by the Ychsma through intermediaries, challenging views of pre-Inca regionalism and establishing a multidisciplinary toolkit for tracing ancient exchange.