Eagle
The Eagles of the Misty Mountains are a race of ancient, noble, and powerful birds who serve as both rescuers and allies to the company, intervening at critical moments to save them from destruction and later participating in the Battle of Five Armies. Their appearance is always sudden and decisive, turning the tide of seemingly hopeless situations. They are not kindly birds in general, but the ancient race of the northern mountains were the greatest of all birds, proud and strong and noble-hearted, and they did not love goblins or fear them.
Nature and Character
The Eagles are not kindly birds in general; some are cowardly and cruel. But the ancient race of the northern mountains were the greatest of all birds, proud and strong and noble-hearted. They did not love goblins or fear them. When they took any notice of them at all, which was seldom, for they did not eat such creatures, they swooped on them and drove them shrieking back to their caves, and stopped whatever wickedness they were doing. The goblins hated the eagles and feared them, but could not reach their lofty seats or drive them from the mountains. The Lord of the Eagles of the Misty Mountains had eyes that could look at the sun unblinking, and could see a rabbit moving on the ground a mile below even in the moonlight.
Rescue from the Wargs and Goblins
The Eagles first appear when the company is trapped in trees by Wargs and goblins, with fire closing in around them. Gandalf had climbed to the top of his tree, ready to spring down among the spears of the goblins, when the Lord of the Eagles swept down from above, seized him in his talons, and was gone. Other eagles swooped down, seizing the dwarves and carrying them away. Poor little Bilbo was very nearly left behind again, just managing to catch hold of Dori's legs as Dori was borne off last of all, swinging in the air with his arms nearly breaking. The eagles carried them to the Great Shelf, a wide shelf of rock on the mountain-side, where they were set down safely. The Lord of the Eagles would not take them anywhere near where men lived, for they would shoot at them with their great bows of yew, thinking they were after their sheep. The eagles had brought up dry boughs for fuel, and they had brought rabbits, hares, and a small sheep for the company to eat.
Alliance with Gandalf
Gandalf and the eagle-lord appeared to know one another slightly, and even to be on friendly terms. As a matter of fact, Gandalf, who had often been in the mountains, had once rendered a service to the eagles and healed their lord from an arrow-wound. This prior kindness explains the eagles' willingness to help the company. The Lord of the Eagles became in after days the King of All Birds and wore a golden crown, and his fifteen chieftains golden collars made of the gold that the dwarves gave them.
Role in the Battle of Five Armies
The Eagles had long had suspicion of the goblins' mustering; from their watchfulness the movements in the mountains could not be altogether hid. So they too had gathered in great numbers, under the great Eagle of the Misty Mountains, and at length, smelling battle from afar, they had come speeding down the gale in the nick of time. They it was who dislodged the goblins from the mountain-slopes, casting them over precipices, or driving them down shrieking and bewildered among their foes. It was not long before they had freed the Lonely Mountain, and elves and men on either side of the valley could come at last to the help of the battle below. Bilbo, who had taken his stand on Ravenhill among the Elves, was the first to see them, crying out "The Eagles! The Eagles!" as they came down the wind, line after line, in such a host as must have gathered from all the eyries of the North. Dain crowned their chief with gold and swore friendship with them forever.
Significance
The Eagles embody the theme of unexpected rescue and the value of past kindness. Their interventions are not merely deus ex machina but are earned through Gandalf's prior service and the inherent nobility of their race. They represent a force of nature that opposes the evil of goblins and Wargs, and their presence in the story underscores the interconnectedness of all free peoples in the struggle against darkness. Bilbo never saw them again except high and far off in the battle of Five Armies, but their role in the tale is decisive and memorable.