He was informed by his scientists that one sparrow eats about 4.5kg of grain each year. They said that according to those calculations, for every million sparrows killed there would be grain (and therefore food) for 60,000 people.
With only that information and a stubborn unwillingness to listen to anything else, he launched the Great Sparrow Campaign in which all citizens were expected to participate and kill as many sparrows as possible.
On 13 December 1958 alone, 194,432 sparrows were killed! Hundreds of millions were killed during the duration of the campaign and the sparrow almost became extinct in China.
What the scientists failed to mention, was that sparrows eat insects like locusts, and that locusts do much more harm than sparrows can. With no sparrows in sight, the locusts did indeed move in and had free reign.
Suddenly Mao Zedong realized what an eco-system was and hurriedly imported sparrows from the Soviet Union, but it was too late. The overflow of insects contributed to the Great Chinese Famine (1958-1961) in which approximately 30 million people starved to death!
