Fishing with birds

Cormorant fishing

Chinese fisherman with one of his cormorants on Erhai Lake near Dali, Yunnan. The bird's throat snare is visible via the constriction in the bird's neck.

Cormorant fishing is a traditional fishing method in which fishermen use trained cormorants to fish in rivers. Historically, cormorant fishing has taken place in Japan and China since about 960 AD It is described as a method used by the ancient Japanese in the Book of Sui, the official history of the Sui Dynasty of China, completed in 636 AD. This technique has also been used in other countries but is currently under threat in China. 

To control the birds, the fishermen tie a snare near the base of the bird's throat. This prevents the birds from swallowing larger fish, which are held in their throat, but the birds can swallow smaller fish. When a cormorant has caught a fish in its throat, the fisherman brings the bird back to the boat and has the bird spit the fish up. Though cormorant fishing once was a successful industry, its primary use today is to serve the tourism industry.

The types of cormorants used differ based on the location. In Gifu, Japan, the Japanese cormorant (P. capillatus) is used; Chinese fishermen often employ great cormorants (P. carbo). Darters (anhinga), which are very close relatives of cormorants, are also used for this fishing technique on occasion.

Source: https://en.wikipedia.org/wiki/Cormorant_fishing