Symbolism, Imagery, Allegory
Things don't go well for Merlin when he lives at his grandfather's palace in South Wales. Not least on his worry list is the fact that Uncle Camlach wants to kill him to secure his throne. Merlin's faithful servant, Cerdic, tells him he has to keep his wits about him.
Specifically, he doesn't want Merlin to feel too confident in his own strength and powers. Cerdic thinks that Merlin's name (after the merlin falcon) has a lot to do with Merlin's own self-image: "I've watched you. You go your own way, and sometimes I think you're nearer to the wild things than to men. You know she called you for the falcon?" (I.3.41).
To get across the sense of danger that Merlin faces, Cerdic gets all symbolic on him, comparing young Merlin's vulnerability and power to two birds: the falcon and the ring-dove.
He's basically saying, "Look, whippersnapper, you may think you're as fierce as a falcon, but you're really just a tasty little tidbit to the strong." Check it out:
"…the ring-dove has many enemies because her flesh is sweet and her eggs are good to eat. But she lives and she prospers, because she runs away. The Lady Niniane may have called you her little falcon, but you're not a falcon yet, young Merlin. You're only a dove…Live by keeping quiet, and by running away." (I.3.45)
So Cerdic's advice at this time is simply to "Run away and live to fight another day." And Merlin lives by this rule for a while—until Cerdic's analogy bites him in the butt. As they survey the hill in Segontium, Merlin sees a real merlin chase and kill a real ring-dove:
The dove lay dead, breast downwards, wings still spread as she had struck the stones, and with blood smearing bright over the iris of her neck feathers. On her lay the merlin. The steel ripping-claws were buried deep in the dove's back, the cruel beak half driven in by the crash. (I.9.46)
What's Cerdic got to do with this? This Wild Britain moment shows Merlin that sometimes even running away isn't going to cut it. In fact, it's Cerdic's own symbolism that convinces him it's time to start acting more like a falcon.