The account of the river and pond Ducks may appropriately be closed with the exquisitely beautiful Wood or Summer Duck (Aix sponsa) and its near relative, the Mandarin Duck (A. galericulata). They are small Ducks, neither exceeding twenty inches in length, with a small bill, which is much shorter than the head, and has a very large, broad nail at the tip. In the adult male the head is crested and the colors throughout are rich and varied.