In 1958, Chairman Mao Zedong of China introduced his “Four Pests” hygiene campaign, meant to eliminate rats, flies, mosquitoes . . . and sparrows. He ordered the killing of sparrows because he believed they ate grain seeds and prevented farmers’ crops from growing.

Mao’s officials mobilized people in cities and in the countryside. Everyone was urged to bang on drums and clash pots and pans, to frighten the sparrows and keep them airborne until the birds dropped dead from exhaustion. Nests were destroyed, eggs broken, baby birds killed. The plan worked all too well. By 1960, sparrows—and a number of other bird species—were driven to near extinction.

The delicate balance of nature was upended, with tragic results. Crop-eating insects were able to thrive, unopposed. In particular, swarms of locusts—a favorite food of sparrows—stripped bare the fields and crops, and millions of Chinese people died of starvation. Later Mao removed sparrows from the list.

Here’s a short video about it. Warning, though. It’s pretty disturbing.