How do you say the word “owl” in Greek?

As Sokratis Di said, κουκουβάγια [kukuvaʝa] in Modern Greek. The proposed etymology is that it’s onomatopoeic, with kukuvau! the Modern Greek for “hoot! hoot!”, and Aristophanes’ ancient equivalent being kikkabaû! (“cry in imitation of the screech-owl’s note”).

The Ancient Greek is γλαύξ, /glaúks/. The ancients guessed that it was derived from glaukos, “blue”, because of the owl’s sparkling eyes (?!) Chantraine’s Etymological Dictionary just mutters “no definite etymology”.