Thursday, September 24, 2015
On Saturday, 9/19, I was witness to a miracle that occurs twice every year!
Monarch butterflies on a Common Milkweed plant (photo: Gay Schroer)
Every year—usually during March in the spring and the last week or two of September—the Monarch butterflies migrate through our yard. This miracle of nature never ceases to amaze me. Now I’m not talking about the 3 or 4 Monarchs you may see feeding or resting in your flower garden during the summer months. These migrating Monarchs are already three or four generations removed from those summer butterflies. The summer Monarch generations have a short adult lifespan—only three to five weeks, compared to eight to nine months for the migrators, or the so called super generation.
In the spring of the year, usually during the second week of March, clouds of Monarch butterflies migrate from their wintering grounds in the mountains of Mexico to various locations in North America as far north as Canada. This generation of Monarchs has already survived a long southward flight in the fall. They have evaded a host of dangers, including predatory birds and vehicle collisions, storms, winds and cold. Those that reach their wintering grounds in Mexico are the only Monarchs left that can produce a new generation.
As they pursue their migration path north and eastward in the spring they seek out the milkweed plants necessary to the survival of their species, upon which they lay their eggs, recolonizing the southern United States before they die. Soon these eggs hatch and the emerging caterpillars feed on the milkweed plant, which is so crucial to their survival. These caterpillars then metamorphose into the familiar orange and black adults, which in turn pursue the milkweed ever northward as winter loses its grip on the land. They in turn lay their eggs, etc., etc., continuing this life cycle throughout the summer. Before the summer’s end there are once again millions of Monarchs inhabiting the northern U.S. and southern Canada.
When the late Summer and early Fall generation emerges they are biologically and behaviorly different from their summer ancestors. The shorter days and cooler temperatures trigger changes. Even though these “migrators” look like the summer adults, they won’t mate or lay eggs until the following spring when their generation has left the mountains of Mexico. These are the Monarchs that migrate through my St. Peters, Missouri, yard each late summer and early autumn.
At first you may ask, “What’s so great about that? Other animals migrate.” But stop to think—this is a creature that weighs less than a paper clip and is as fragile as a piece of tissue paper; yet it survives a journey of thousands of miles against huge odds. This is not even the creature that made the original journey. It is several generations removed from that original Monarch. How did it know to find it’s final destination—right down to the same specific tree that it’s ancestor rested upon in Mexico several generations ago? How does it know, each year, to rest for a night in one particular pin oak tree in my back yard—even though there are dozens of trees of the same species in my yard and surrounding yards? To learn more about the amazing Monarch Butterfly and its life cycle Click Here.
Butterfly Weed, with its striking orange blossoms, attracts other creatures as well as Monarchs (photo: Gay Schroer)
I consider this creature a true miracle of nature—but there is a problem. As we humans spread out more and more into the suburbs and the surrounding countryside, we destroy the natural growing habitat for the milkweed plant. In addition, as more and more land is cleared for agriculture, shopping malls, parking lots and other accoutrements of civilization we rely on herbicides to keep the “weeds” down. There is less and less milkweed to nurture the Monarchs. In recent years scientists who study the Monarchs have noted an alarming decrease in their populations.
What can I do, you may ask? We as individuals may not be able to solve the whole problem, but we can help by growing milkweed in our gardens. If every gardener nurtured a small patch of milkweed it would give this valiant little flyer a place to lay eggs for the next generation. Milkweed is a sun loving plant, so shade gardens are not to its liking. However, my husband grows Butterfly Weed in a pot on the deck of our Ozarks cabin, and each year it draws dozens of Monarchs to its bright orange flowers.
To learn more about growing milkweed in your garden Click Here. Even though common milkweed presents a containment problem in the garden, this website offers several tips on containment measures. It also gives information on other forms of milkweed—most notably, Butterfly Weed, which is a very striking plant if your garden has a suitable site for it.
Submitted by Gay Schroer, World Bird Sanctuary Volunteer/Photographer