Correct:) the great eagles is the answer, and I was specificaly thinking of their arrival at the battle of 5 armies, though it does fit the others instances to,
and the gnarled swords did refer to their talons
edit: and the eagles came as night was falling on the battle of 5 armies. When Bilbo regained consciousness and found the battle over and won, it was the following morning. So the eagles' attack was through the night