In 1958, the Communist Government of Mao, in China, declared war on the tree sparrow (considered a pest). They were systematically killed, mobilizing a lot of people, of all ages.

A couple of years later, the absence of sparrows destabilized ecological balance (also deforestation and abuse of chemicals), and resulted in large numbers of pests like locusts and other insects, which devastated crops causing great hunger. It is estimated that about 30 million people died.

The same government had to take responsibility and 250,000 sparrows were imported from the Soviet Union.