Natty's Birds of a Feather Costume Tutorial
Added Oct 2, 2011
Above is a view of the back of the wing. Notice the layer along curved edge (C) peaks over, and the layer along the top edge (A) is showing by opening feather sets and placing each layer on either side of the edge.
Also, the thread color should match your wing base color on this side so that your stitching isn't too noticeable.