The War on the Sparrows

Perhaps the crowning example of general ignorance to ecology is the "Four Pests Campaign" initiated by Mao Zedong in 1958. An explanation of this requires some political background, however. Mao, having recently established his Communist government in China, had set about creating a series of reforms known as the Great Leap Forward. One of the chief goals of these was to increase Chinese farmers' grain production. To that end, he declared that sparrows, which ate grain, were to be exterminated.
Farmers took this very seriously--they banged pots and pans to scare sparrows away, destroyed their nests, and shot them on sight. On the surface, this seemed to work; it was not uncommon for crops to become quite successful once the birds were disposed of. However, it did not take long for the flaws to begin to show.
Most Chinese peasants, after all, were not well-versed in ornithology. To them, any small brown songbird was a "sparrow," and the techniques used to get rid of the sparrows affected other birds too. With the number of birds decreased, grain-eating insects experienced a population boom, thus contributing to the famine that would end up killing millions of starving Chinese. Mao's War on the Sparrows had backfired spectacularly.