In 1958, when China ordered a nationwide sparrow slaughter to protect grain crops, what followed was 2 million human deaths

In 1958, the Chinese government declared war on sparrows. Citizens from coast to coast were organized to bang drums and wave flags and make noise day and night anything to keep the birds from landing until they died of exhaustion. Millions of eggs were wiped out. Nests were destroyed. In two years, the sparrows had been effectively exterminated all over much of China.

The target was to protect grain. What followed instead was catastrophe.

Now a new study by researchers at the University of Chicago and the National Bureau of Economic Research has quantified a theory long suspected by environmental historians: that killing off the sparrows dramatically worsened the Great Chinese Famine. A NBER working paper by Eyal G. Frank and coauthors found that the sparrow-eradication campaign led to nearly two million additional deaths between 1959 and 1961.

The logic made sense, until it didn’t
Mao Zedong's Four Pests Campaign, part of the Great Leap Forward launched in 1958, targeted rats, flies, mosquitoes, and sparrows. What did the sparrow do? They ate grains. This seemed reasonable on the surface. Sparrows do eat seeds and grain, and getting rid of them seemed like an easy way to improve harvests.

What the government didn’t realize, despite the warnings of scientists, was that sparrows also eat insects. Most of them. Adult sparrows feed their young almost entirely on insects, including locusts and planthoppers, some of the most destructive crop pests in Asia. If you take away the sparrows, you take away an important control over those pests.

And that’s exactly what happened. As the birds disappeared, insects flourished, damaging the crops.

The numbers are telling a grim story
The researchers applied ecological modeling to determine which counties in China were naturally suitable for sparrows, and then compared the fate of agricultural output in those areas with that in regions where sparrows were never common. The results were striking.

For each standard unit of higher sparrow suitability, Frank et al. reported that counties where sparrows could have thrived had rice yields that were 5.3% lower and wheat yields that were 8.7% lower, compared with counties where sparrow suitability was lower. In total, the researchers estimated that the elimination of sparrows was responsible for about 19.6 percent of the total decline in national crop production during the famine years.

That alone would have been devastating, but the government made it worse.

The failed system turned a crisis into a disaster
Instead of acknowledging the damage being caused by the campaign, the central government even increased food procurement quotas for counties that were suitable for sparrows, the very counties that were hardest hit by pest infestations. Officials said the sparrow eradication was expected to boost output. So the people who grew the grain had it stolen from them even as the harvests failed.

This pattern is well known. A key driver of famine mortality was the rigidity of China’s state procurement system, according to research by Meng, Qian and Yared in the Review of Economic Studies. Grain was seized from rural communities even as people starved, because quotas were set in advance and poorly adjusted to local conditions. The sparrow study elaborates on this result, showing that sparrow-suitable counties suffered heavier procurement burdens as well as lower yields, a double blow that was evident in death and birth records.

What this means for us today
This is not just a historical footnote. It is a case study of what happens when ecosystems are viewed as inconvenient obstacles rather than systems that we depend upon.

The larger point is made clear in research in the Journal of Pest Science. A global analysis of 179 studies, by Díaz-Siefer and colleagues, found that wild birds consistently reduce crop damage and pest abundance, and increase yields, providing a form of pest management that is natural and cost-free, and that industrial agriculture has largely failed to account for.

China's sparrow campaign was an extreme version of ignoring that reality, and the consequences were extreme as well.

By 1960, with crops failing all over the country and starvation spreading, the government quietly took sparrows off the Four Pests list and replaced them with bedbugs. It was too late for the birds; they were mostly wiped out. It has been difficult to verify this independently, but reports claim that in a bid to repopulate, China imported around 250,000 sparrows from the Soviet Union.

By 1965, rice and wheat yields in sparrow‐suitable counties had returned to normal. The sparrows returned. The crops came back. The millions who died didn’t.

The lesson governments need to learn
The Four Pests Campaign is a chilling reminder of what can happen when policy ignores scientific consensus. At the time, experts warned that the eradication of sparrows would throw ecosystems out of balance. They were overruled. The result, as Frank and his co-authors put it, was a measurable contribution to the largest famine in human history, one in which tens of millions of people perished.

The willingness of a government to listen to its scientists is a direct lifeline to the survival of its people. China's sparrow campaign is what happens when that line breaks.