The imagery of the falcon within the gyre isn’t much removed from the imagery of a pern in the gyre. Could Yeats have misspelled pern (spelling it perne)? If one particular thinks of Yeats’s perne for a hen of prey, then Yeats’ is comparing the sages to birds of prey. https://chance220mv.popup-blog.com/22289918/considerations-to-know-about-perne-pentru-bebeluși