It took more than a century for scientists to work out what had happened, but it appears that the locusts retired every winter to hibernate and breed in the loamy soils abutting the winding rivers of the high plains east of the Rockies. These, it turned out, were the very places where new waves of incoming farmers were transforming the land through ploughing and irrigation—actions that killed the locusts and their pupae as they slept. They couldn’t have devised a more effective remedy if they had spent millions of dollars and studied the matter for years. No extinction can ever be called a
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