The winged images in Romantic Poetry

The images of birds are recurrent in Literature. In fact, the symbolism associated to wings and birds is ancient and throught the history of literature new different meanings have been added, attaching new meanings to the words. In Romantic Poetry, birds usually elevate the lyric speaker and take him/her to another world - A Platonic world of pure ideas where the ethereal trascends the earthly world of mortality and decay.

Compare and contrast the images of the raven and the nightingale in the poems by Edgard Allan Poe and John Keats, What symbolism has tradition attached to these two birds? And how do these two romantic poets recreate and give new meaning to these images?