Monarch butterflies are migrating, leaving their breeding grounds and making their way to their southern wintering grounds, thousands of miles away. Monarchs passed through Virginia this spring on their way north; a few spent the summer here, but most continued further north. Now, with the days growing shorter, I knew it wouldn’t be long before the monarchs came back through on their way south.
I witnessed the phenomenon of the monarch migration from Virginia for the first time last fall. I was putting in some flower bulbs when I noticed a monarch above me. A few minutes later, another passed by, headed in the same direction. To my surprise and delight, over the next few days, I watched dozens of butterflies making their way south, not in their usual meandering fashion, but making a “beeline” south.
Monarchs are the only species of butterfly that migrates both north and south, as the birds do, in a yearly cycle, but no one individual makes the entire round trip. The length of these journeys exceeds the normal lifespan of most monarchs, which is less than two months for butterflies born in early summer. The last monarch generation of the summer enters into a non-reproductive phase known as diapause and may live seven months or more; it is during this phase that the monarch flies to its overwintering site. The generation that overwinters generally does not reproduce until it leaves its wintering grounds sometime in February or March.
These fragile creatures, weighing less than half a gram, fly unbelievable distances to reach their final destination. “Our” monarchs born east of the Rockies leave the fields and forests of North America to migrate as far as 2,500 miles to the Oyamel fir trees in the Sierra Mountains of Mexico; those born west of the Rockies travel to small eucalyptus groves on the Baja California coast.
The monarch population that summers in eastern North America has been dwindling due to deforestation in their Mexican wintering grounds and a loss of milkweed, the host plant of the butterfly’s larvae, in their summer home. Milkweed plants, and many other native plants that benefit wildlife, are often bulldozed to make way for housing developments and shopping centers. Here in rural western Virginia, monarchs and other butterflies feed on goldenrod, milkweed, butterfly weed, asters, thistle, dame’s rocket, and joe-pye weed, among others.
I am sad to see the monarchs go. In a way, they are taking summer with them for their departure signals the end of the long, lazy days of summer. Gone soon, too, will be the wildflowers that once so lavishly decorated the fields, woods, and roadsides. But I know these orange and black marvels will be back next spring to start the cycle all over again. As I watch them winging their way south, I wish them well and hope that Mother Nature will be kind to them during the long journey ahead.