How do the hawks develop the theme that the universe conspires to help one realize ones personal legend?

Santiago notices hawks flying in the desert at night. The hawks reveal a secret message to Santiago.

Suddenly, one of the hawks made a flashing dive through the sky, attacking the other. As it did so, a sudden, fleeting image came to the boy: an army, with its swords at the ready, riding into the oasis. ch 2

The hawks, through their own violence, foreshadow violence yet to come to the oasis. There is a sense that the desert as a microcosm of the whole world that tries to reveal itself to people who no how to look for it.