Why does Poe choose a raven?

Answer 1

The plot of The Raven by Edgar Allan Poe is simple. He believes that there is a Raven (which is inside of his mind) flying around. The Raven is his consciousness reminding him of his lost love, Lenore.

In the end, he is left all by himself - alone for evermore

Answer 2

There's a bit of controversy with that one. My suggestion would be to read Philosophy of Composition (by Poe) which goes over how Poe wrote The Raven and why he wrote it that way. You should also consider Poe's biography and look for the similarities between Poe and the narrator.
His family life

Answer 3

It is a poem, which darkly alludes to the narrator's lost love, and it may reflect the same sort of love lost by Poe. The titular bird has come to reside in the house, like a persistent, painful thought residing in one's memory.

Answer 4

Because its a creepy bird, the melancholy mood of the poem, and the symbolism of ravens as birds of ill-omen. Plus ravens can mimic words.