Pekin duck, or Long Island duck (Anas platyrhynchos domestica, or Anas peking), is a breed of domesticated duck

Domesticated duck

Domesticated ducks are ducks that are raised for meat, eggs and down. Many ducks are also kept for show, as pets or for their ornamental value...

 used primarily for egg and meat

Duck (food)

Duck refers to the meat of several species of bird in the Anatidae family, found in both fresh and salt water. Duck is eaten in many cuisines around the world.-Types of ducks:The most common duck meat consumed in the United States is the Pekin duck...

 production. It was bred from the Mallard

Mallard

The Mallard , or Wild Duck , is a dabbling duck which breeds throughout the temperate and subtropical Americas, Europe, Asia, and North Africa, and has been introduced to New Zealand and Australia....

 in China

China

Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...

. The ancestors of those ducks originated from the canal

Canal

Canals are man-made channels for water. There are two types of canal:#Waterways: navigable transportation canals used for carrying ships and boats shipping goods and conveying people, further subdivided into two kinds:...

s which linked waterways in Nanjing

Nanjing

' is the capital of Jiangsu province in China and has a prominent place in Chinese history and culture, having been the capital of China on several occasions...

 and originally had small bodies and black feathers. With the relocation of the Chinese capital to Beijing

Beijing

Beijing , also known as Peking , is the capital of the People's Republic of China and one of the most populous cities in the world, with a population of 19,612,368 as of 2010. The city is the country's political, cultural, and educational center, and home to the headquarters for most of China's...

, supply barge traffic increased in the area which would often spill grain

GRAIN

GRAIN is a small international non-profit organisation that works to support small farmers and social movements in their struggles for community-controlled and biodiversity-based food systems. Our support takes the form of independent research and analysis, networking at local, regional and...

 on which the ducks fed.