that (to me) odd question folk seem to always ask, which probably has been beaten dead here before I arrived--"why didn't they just give the ring to the eagle to take to Mount Doom."  I always saw the steed of the winged wraiths as the twisted version of the eagles. We have the oppositions of elf/ork, ent/troll, and Rohan horse/Black Rider horse so I always assumed that these had a similar relationship to the eagles. I feel even more so every time I read the final battle scene when the Eagles come to defy the Nazgul. Though they never really get a chance to confront the flying beasts of the Nazgul (because the wraiths are recalled by Sauron when Frodo puts on the ring), I can't help but think they might have at least "unhorsed" (or un-birded?) the Nazgul.

Bringing me back to that "odd question." As sentient beings (or even if they weren't), wouldn't the eagles be just as likely to be affected by the ring as men or elves or wizards or dwarves or hobbits? Would they be any more or less reliable as ring bearers?