Hmm, looking at that reference and back at the sprites, the head size looks fine. If anything, I think the right ear might be somewhat off proportion. Maybe it's just the perspective, but it seems a little too small in width. It doesn't seem to..."extend inwards enough", if that makes any sense?
Other than that, good stuff. I like what I see! =3
Other than that, good stuff. I like what I see! =3