Aww... It's so cute! But in a reptilian kind of way. o.O
Anyway, I really like the close-up and how you have framed this piece with the head in the middle and all.. I think there's just enough contrast and saturation to really make a good impression overall, so that's good.
I'm not too fond of the way the grass/stalk obscures a bit of the face, as it is quite distracting, but I guess it adds more depth to things as well?
A vignette wouldn't hurt.. but the naturalness of the piece already makes it quite profound, so I don't think that is specifically required, as such.