From majestic Amazonian macaws and highland Andean hawks to tiny colorful tanagers and tall flamingos, birds and their feathers played an important role in the Inka empire. Claudia Brosseder uncovers the many meanings that Inkas attached to the diverse fowl of the Amazon, the eastern Andean foothills, and the highlands. She shows how birds and feathers shaped Inka politics, launched wars, and initiated peace. Feathers provided protection against unpredictable enemies, made possible communication with deities, and brought an imagined Inka past into a political present. Richly textured contexts of feathered objects recovered from Late Horizon archaeological records and from sixteenth- and seventeenth-century accounts written by Spanish interlocutors enable new insights into Inka visions of interspecies relationships, an Inka ontology, and Inka views of the place of the human in their ecology. Inka Bird Idiom invites reconsideration of the deep intellectual ties that connected the Amazon and the mountain forests with the Andean highlands and the Pacific coast.