Ive heard different names from different sources, but the main ones Ive heard are Bubo, Hesiod or Nyctimene, however to think of the owl as a separate entity is in and of it's self a paradox as it is described in greek mythology that the owl of athena(athene) is in fact athena herself as this is how she was able to manifest herself physically on earth, Athena was(is) a shape-shifter, to deliver wisdom and aid to those she felt was worthy. Thus in point of fact the name of the owl would indeed be Athena.