The imagery from the falcon within the gyre isn’t far faraway from the imagery of the pern in the gyre. Could Yeats have misspelled pern (spelling it perne)? If one particular thinks of Yeats’s perne like a chicken of prey, then Yeats’ is comparing the sages to birds of prey. https://jasperhjeed.slypage.com/22406072/the-single-best-strategy-to-use-for-pernuțe-pentru-copii