The timing of easterners’ migration into the Great Plains coincided with devastating swarms of locusts. The insects, really a species of grasshopper in swarming phase, mainly stayed in the Rocky Mountains until the jet stream facilitated movement to the Plains, where heat helped them breed.
The hungry scavengers devoured all crops in their path and sometimes, fences, blankets, and wool. When the food was gone, the swarms moved on in a flying cloud. Insects caused an estimated $200 million in crop damage in Colorado, Wyoming, Nebraska, and elsewhere. In Minnesota, where author Laura Ingalls Wilder witnessed the plague as described in On the Banks of Plum Creek, locusts destroyed more than 13 million bushels of wheat and 7 million bushels of oats. “The rasping whirring of their wings filled the whole air,” wrote Wilder, “and they hit the ground and the house with the noise of a hailstorm.”
The largest swarm, recorded in 1874, covered 198,000 square miles. A report that year showed only one family in 10 had enough food for the winter. The government relaxed Homestead Act residency rules so settlers could seek temporary work elsewhere. In 1875, Uncle Sam spent $30,000 on seeds for farmers. Less than 30 years later, locusts mysteriously died out.