Originally Posted by
biminiblue 
Trach, the hummingbird is light green on his entire back, the topnotch is black, his tummy is greyish - almost like a juvenile coloring. I really think it's some mutation - or I've discovered a new species.
I don't have a good camera, and my point and shoot is never handy when he pops in.
You're gonna have to get a picture. Lot's of them can go mohawk! From your description it's a female ruby throated. The crest is from being territorial.