There are many early European accounts of tapirage written over the past three hundred years. This one is from A. R. Wallace, A Narrative of Travels on the Amazon and
It appears that Wallace is describing a Greenwing (Red and Green) macaw, or a Scarlet macaw. There are many other descriptions of tapirage, similar to this, throughout the Eighteenth and Nineteenth Centuries. Most are not very descriptive about the type of macaw, although all of them reference plucking blue or green feathers and rubbing the exposed skin with various substances (sometimes a frog poison - there are also references to certain fats, tree resins, and dyes being used on the bird's skin). It also seems likely they were plucking large areas of feathers at once, and used parrots that were kept in small aviaries at each village.
After reading these historical accounts of the practice of tapirage, all we can think is the natives of the Amazon had some very angry parrots on their hands!