I'm sorry I can't help you with the bird ID but is sure is a nice photograph. Looks like a hawk of some kind. Must be pretty big judging by the size of the snake, huh?
The photo does not look too dark or too light to me at all. Sometimes I'm sorry I didn't opt for the 80-400mm for the extra reach when I see photos such as this. The hawks around here are much too far away for the 70-200VR even with the TC17.