It is psychological interpretation that if a man is highly alert than he is highly timid. He always prepared to a defence of an imaginary attack. But generally we think it is a highly alert bird. In fact the crow is said to have only one eyeball which rolls from one eye-socket to the other depending upon the eye used. Probably this is the reason why the crow looks only sideways, with one eye, which is at a lower level than the other
There is a reference in Ramayana of a meeting of Sita Devi and Hanuman when he met Her in the Ashoka Vanam and subsequent dialogue between them.
Pleasure and pain, happiness and misery alternately impel human beings, Sita is no exemption. with the meeting Hanuman envoy of Lord Rama,Sita was consoled to some extent, but also pained by the thought that Rama had not forgotten her, but was thinking of her, grieving and searching for her. With flowing tears, she recounted incidents of their forest life, to be communicated to her lord.
“Once in Chitrakuta my lord and I wandered about in the grove beside the river and became weary and rested on the ground. He laid his head upon my lap and fell asleep. While thus, a crow came down and hungrily pecked at my bosom, I drove it off, but again and again it returned and troubled me. I then flung a pebble at it. But even that had no effect. Rama was roused from slumber and saw me thus troubled and weeping in pain. At first when he saw what the matter was and found it was but a crow, he was inclined to laugh at my discomfiture. But he saw the bruise the crow had made and discovered that the bird was really an Asura Jayanta . Rama invoked the Brahmasthra in a blade of grass and threw on Jayanta, which chased him all over the three worlds, and Brahma, Vishnu and Siva could not offer him any help.
Finally, Jayanta had to come and prostrate before Lord Rama in total Saranagati. The ever compassionate Lord pardoned him, but asked him to give away one of his eye balls to the Brahmasthra, as the weapon, once released, cannot be retracted and appeased without hitting a target.
Tell him of this incident. O Hanuman, I cannot wait for many more days. Tell him to come quickly and save me.”
From this reference It is presumed that because of this the crow is cockeyed and always in the fear of being attacked by brahma astra and flies away even with the slight sound.