It's certainly better than a flat bird. I think it would look far less abnormal without the skidding, but I'm sure you know that. When I imagined it, I thought of just slight tilting up and down in the direction of flight, but what you have looks good too.
EDIT: I just played it, and I saw that you updated both things. It's much better now :) The only other thing I could think of is to add a few random wing flaps when gliding, as right now the bird just seems flat when doing so.