Thanks for uploading! I have looked at your model file, and while it's overall good, I suggest working on the wings a little bit more. Looking at them in front view shows that they are a bit to linear, also the edges of the wings are composed of unnecessary many polygons. Also there should be at least one more edge loop in the center of the wing, so it can bend properly. I didn't try to animate it yet, but I think the model would benefit from those changes.