They haven't figured out why. The suspicion is a big acorn crop the year before that built populations up a lot. And then not enough food the next year. But the scale of the migrations was so large. In checking some history just now, my statement of thousands was way low -- some estimates of half a billion in one migration of the mid-1800s. I can't even imagine that.
They haven't figured out why. The suspicion is a big acorn crop the year before that built populations up a lot. And then not enough food the next year. But the scale of the migrations was so large. In checking some history just now, my statement of thousands was way low -- some estimates of half a billion in one migration of the mid-1800s. I can't even imagine that.