The opening stanza was a chilling way to begin. I like the rhymes every two lines, but I think that, on the end of the third line in this stanza, it needs a comma.
The second stanza's rhymes were just as smooth as the first. I enjoyed the imagery of a bird's silhouette up against the night sky, though did you mean
'To if THEY would die' ?
I love the third stanza, as I have terrible memories of a crow's noise. Once, I was on a walk in a field nearby, minding my own business, before being caught completely unaware by a crow in a tree I was passing by. It scared me to death! I would use a couple of pronouns in these four lines, though, as it gives some good variation to poetry. That's a key : when you're writing a poem, go through each word and think to yourself, " is there a better alternative?". Adjectives, nouns and adverbs can all be rethought.
I thought that the final stanza was a good close to it. I liked the length and the title. Well written :)