Myths represent them to represent higher states of being angels, spirits or vahanas and their nocturnal nature of the ominous hoot which allies with darkness, death and blind ignorance. Then they become dark forces of the irrational. The owl was a symbol of solitude and depicted hermits in prayers. They were ill omen in dreams. They symbolise mourning and desolation. They were also agents of magic practices. They were called ‘corpse birds’ and considered unclean. But their association with the otherworld and its mysteries, the owl was thought to be cognizant of future events and became an emblem of wisdom also. (see posting on Uluka, Birds in the Hindu Way of Life)
Hara Hara Mahadeva. by Yogi Ananda Saraswathi.
and added by Haley Goswami from Facebook
there is also an explantion of why owl is lakshmi's vahana . in an agarian civilazation like ours corps were the source of money and well being . in other words corps=lakshmi . and it was owl which ate up rodents and pests protecting the corps at night . so lakshmi the goddess of money and harvest rides on owls .
however it is only in bengal , assam and orissa that she is seen on her vahana .