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

Area of Science:

• Archaeology
• Ancient DNA Analysis
• Isotope Geochemistry

Background:

• Pre-Hispanic Andean societies highly valued Amazonian parrot feathers as status symbols.
• Acquiring these feathers involved crossing the challenging Andean mountain range.
• The Ychsma culture flourished in the Late Intermediate Period (ca. 1000-1470 CE) at Pachacamac.

Purpose of the Study:

• To reconstruct the complete journey of Amazonian parrot feathers found in an elite Ychsma tomb.
• To investigate the trade networks and logistics involved in interregional exchange.
• To challenge existing views on pre-Inca regionalism.

Main Methods:

• Ancient DNA (aDNA) analysis to identify parrot species and genetic diversity.
• Stable isotope analysis (carbon and nitrogen) to determine diet and origin.
• Spatial modeling, including species distribution and landscape resistance modeling, to identify trade routes.

Main Results:

• Genomic data identified four Amazonian parrot species (Ara macao, A. ararauna, A. chloropterus, Amazona farinosa) with high genetic diversity, suggesting wild population sourcing.
• Isotope analysis indicated a C4-rich coastal diet, proving birds were transported alive and maintained in the arid coastal environment.
• Specific trans-Andean corridors were identified as key routes for feather exchange.

Conclusions:

• The Ychsma culture operated a sophisticated, managed trade network for exotic goods, likely using intermediaries.
• Feather acquisition demonstrates complex interregional connections predating the Inca Empire.
• A multidisciplinary approach provides a powerful toolkit for tracing ancient exchange systems.