The high Misty Mountains are wild and dangerous, home to many perilous and evil creatures ... giants in the mountain valleys, orcs in caverns under the high peaks. But the tall mountains known to elves as the Hithaeglir are also home to the noble, powerful and wise Eagles ... descendants of Thorondur, servant of the Valar, who still come betimes at need to drive evil from the air and harry the servants of Sauron.
The Eagles are larger than modern eagles: they are large enough to carry a man on their back, fierce enough to strike terror into orcs who have the misfortune to encounter them, and noble enough to gain the lasting friendship of the Wise.

Their eyries are on high peaks far up in the mountains, where none but the strongest wings can fly, but they roam far and wide across Middle Earth, and little escapes the notice of their sharp eyesight.