Have a look at this.
Here is every single instance, when someone used the term "black crow" in all the books, including the person who said it. Try noticing a pattern. (Solution below in the spoiler)
I broke no oaths. Stiv and Wallen flew down off the Wall, not me. The black crows got no place for women.
He can call himself King-beyond-the-Wall all he likes, but he’s still just another old black crow who flew down from the Shadow Tower.
“Black crows, oft as not. Killed me one too,” she said, shaking out her hair.
I’ve meat and beer for twenty, no more. The rest o’ your black crows can peck after their own corn.
“Brave black crow,” she mocked. “Well, long before he was king over the free folk, Bael was a great raider.”
Lord Brandon had no other children. At his behest, the black crows flew forth from their castles in the hundreds, but nowhere could they find any sign o’ Bael or this maid.
“Let him die,” insisted the Lord of Bones. “The black crow is a tricksy bird. I trust him not.”
“The black crow is a tricksy bird, that’s so... but I was a crow when you were no bigger than the babe in Dalla’s belly, Jon Snow. So take care not to play tricksy with me.”
- Mance Rayder
Harma snorted, her disdain frosting from her nostrils. “What fools these black crows be.”“The next time you answer me with a question, I will give you to my Lord of Bones,” Mance Rayder promised Jon.
You left your homes and came south in your hundreds and your thousands … why, but to escape them? To be safe. Well, it’s the Wall that keeps you safe. It’s us that keeps you safe, the black crows you despise.”
- Jon Snow to the wildlings
“You wanted warriors, didn’t you? Well, there they are. Every one worth six o’ your black crows.”
Your false king is dead, bastard. He and all his host were smashed in seven days of battle. I have his magic sword. Tell his red whore.
Your false king’s friends are dead. Their heads upon the walls of Winterfell. Come see them, bastard. Your false king lied, and so did you. You told the world you burned the King-Beyond-the-Wall. Instead you sent him to Winterfell to steal my bride from me.I will have my bride back. If you want Mance Rayder back, come and get him. I have him in a cage for all the north to see, proof of your lies. The cage is cold, but I have made him a warm cloak from the skins of the six whores who came with him to Winterfell.I want my bride back. I want the false king’s queen. I want his daughter and his red witch. I want his wildling princess.I want his little prince, the wildling babe. And I want my Reek. Send them to me, bastard, and I will not trouble you or your black crows. Keep them from me, and I will cut out your bastard’s heart and eat it.It was signed,Ramsay Bolton,Trueborn Lord of Winterfell.
Edited by Rooseman, 18 January 2014 - 02:50 PM.