It does have a certain charm as it is. Pencil shading can do that. If you want to add something to it without taking away the feeling of the pencil shading, you could simply colorize the picture and perhaps apply a filter to it. Definitely a nice sketch, though. I like that somewhat cute, somewhat sinister look on its face. Nice job with the pose and especially the angle of the back legs, too. But where's its other wing?