This is the wing of a female blackbird ( Greenwell's Glory etc), upper and lower side;
(http://img210.imageshack.us/img210/7073/blackbirdf.jpg) (http://imageshack.us/photo/my-images/210/blackbirdf.jpg/)
I don't suppose anybody will complain if you find one dead on the road and use the feathers, but you should be very careful about doing this. Various substitutes can be used.Waterhen fibres work fine, as does starling dyed with a mixture of dark blue dun and light brown. Dye the dark blue dun first and overdye with brown.