*awi-

"one who observes flights of birds for the purpose of taking omens," 1590s, from Latin auspex "interpreter of omens given by birds," from PIE *awi-spek- "observer of birds," from root *awi- "bird" + root *spek- "to observe." Compare Greek oionos "bird of prey," also "bird of omen, omen," and ornis "bird," which also could mean "omen."

plural (and now the usual form) of auspice (1530s), "observation of birds for the purpose of taking omens," from French auspice (14c.), from Latin auspicum "divination from the flight of birds; function of an auspex" (q.v.).

The meaning "any indication of the future (especially favorable)" is from 1650s; it is attested earlier (1630s) in extended sense of "benevolent influence of greater power, influence exerted on behalf of someone or something," originally in the expression under the auspices of.