Yes, a trans map will give you the "feather boa look" Turn the texture into an inverted b/w picture: The white background should be black (will be transparent in the rendered picture) and the actual texture should be white (will be solid in the picture). The transition between the black and white in the lower edges of the textured parts should give you a nice boa look, especially if you can get a greyscale there that gives a semi transparent look.