You need to click on this picture to see the detail. The light-colored duck has a sort of ruff of feathers on the back of its head - a deformity that is apparently bred for by some duck fanciers. Odd, but no harm to the duck if it has the gene from only one parent. If it has the gene from both parents, it will die in the egg stage and never hatch. The picture was taken in Golden Gate Park, San Francisco, fall 2006.