Chairman Mao and the sparrows

In China, the Great Leader Mao Tse-Tung decided in 1958 to get rid of sparrows, calculating that each bird (the tree sparrow) consumed 4.5kg of grain each year and that for every million sparrows killed, there would be food for 60,000 people.

He mobilised the population to kill the birds, to great effect: at least 2.8millionsparrowswere killed in Shantung province alone. But what Mao had not taken into account was the number of noxious insects the sparrows consumed when rearing their young. The net result was that the following year the rice crop, far from being increased, was significantly down, The idea was quickly forgotten and the birds soon recovered to their normal level.