Meaning of Druidic dusk
the Druidic dusk
= The dusk that was typical at the time of the Druids. / Dusk at the time of the Druids. (With the suggestion that the Druids would have seen such things and found them unremarkable.)
The expression seems to be poor use of English as Druids are a Celtic phenomenon, whereas the Tarahumara Indians are from northwestern Mexico.