The American Pekin duck, or Long Island is a breed of domesticated duck used primarily for egg and meat production. It was bred from the Mallard in China. The ancestors of those ducks originated from Nanjing and originally had small bodies and black feathers. With the relocation of the Chinese capital to Beijing, supply barge traffic increased in the area which would often spill grain on which the ducks fed. Over time, the ducks slowly increased in size and grew white feathers.