@CroTalito, yes, you are right. These two expressions mean two different things, but both use the "crow".
@Chris. Good. Interesting environment where you live... Around here, there are also quite a number of these crows... sometimes I see beautiful eagles too...
As far as Poe goes, I read the poem in Spanish when I was maybe 12, and I was impressed... I found a version here
http://www.heise.de/ix/raven/Literat.../TheRaven.html
It is an incredible poem! (I cannot resist to copy here the beginning...)
Once upon a midnight dreary, while I pondered weak and weary,
Over many a quaint and curious volume of forgotten lore,
While I nodded, nearly napping, suddenly there came a tapping,
As of some one gently rapping, rapping at my chamber door.
`'Tis some visitor,' I muttered, `tapping at my chamber door -
Only this, and nothing more.'