Do they harass poets? [ Alayne asks, her eyebrows raised in both genuine curiosity and the affectation of amazement. ] They've no such reputation in Westeros, though the white ravens wouldn't, would they?

They are bred by the maesters of the Citadel — for in the Seven Kingdoms there is only one. And they are loosed only when summer comes to an end. So I suppose some ravens are never given chance to take wing, given how long the last summer was.