The weather kills them, and the poisoning of milkweed, and the decimation of the forests they went home to. They keep looking: where are the flowers still wild, the trees still undisturbed? Sometimes, they find nothing.
But look what happens when they come. Here is a forest, even now. Have you ever seen a swarm of bees, gathered around the knob of a tree limb? Like that, the closed wings brown as bark, but wait. When they open, listen. What is that sound now, here at the edge of this expanding desert?
One makes no sound. But here are millions, and when they move, if your eyes were closed, you would think: waterfall.
The ancients, seeing them, recognized the spirits of fallen warriors, the souls of mothers lost in childbirth, the souls of children lost when the families had to flee the sites of massacre. The ancients, seeing them in the tree, saw the forests as waiting mothers and fathers, arms open to receive their lost children again.
A recent article in My Modern Met features a recording by nature host Phil Torres, of the waterfall sound made when millions of Monarchs are moving.
There are numerous resources devoted to planting milkweed to mitigate the devastation of Monarch populations.