This is a beautiful drawing, that is certain. The colouring and shadows look great, the feathers look like feathers even if they look a bit like fur in some places, but that might just be me.
The only problem I really have with this work is that it doesn't look like a real wing, no real birds wing is shaped like that.
But that is the only thing I do not like about this drawing and with the skill I can clearly see in this, fixing it should be easy. I find duck wings look quite cool if you are looking for a reference and google Images can supply you with more then enough photos and diagrams is you need them.
(sorry for shortness if you were hoping for something longer)