Monday, July 4, 2011

Where are the Monarch butterflies this year?

Over the years, I have purposely allowed Common Milkweed to naturalize on my land, because it is the food plant of the Monarch butterfly larva.  The area where I live is on the migration route and a breeding grounds for the larvae.  (In fact, the Monarch is the state butterfly of Minnesota.  I consider my place to be a butterfly sanctuary.)  The caterpillars will only eat plants in the Milkweed family -- which include not only the Common Milkweed, but also Butterfly Flower ( formerly known as Butterfly Weed, but renamed "flower" by retail greenhouses) and Aesclapia varieties.   So it's a good idea to have some of these plants in your  butterfly garden if you want to attract Monarchs.

In past years, I could go out into the field this time of year and, within minutes, find either larvae or eggs from Monarchs, as well as see the females fluttering from plant to plant laying more eggs. This year, zilch, zero, nada.  I wanted to find some eggs and/or caterpillars to raise so my little grandson could watch them grow and pupate.  A few years ago his older brother, at around age three, was amazed to see an adult Monarch emerge from the pupa. "Butterfly in there!" he exclaimed in delighted surprise. He also delighted in releasing the butterflies. Now his brother is about the same age and spending daycare time with us, so I wanted to do this project again. I went in search of larvae or eggs, but found not a single one. I must have looked under the leaves of a hundred plants or more, with no luck.  So what happened?

It's hard to say.  Did all those fires in the Southwest kill the Monarchs as they migrated from Mexico or the Gulf states?  Was the long cold spell here in Minnesota this spring too much for those who did arrive?  Are they being killed off by genetically-modified corn pollen from plants with BT (Bacillus thuringensis) built in to kill corn earworms -- and any other caterpillars it comes in contact with?  Is climate change upsetting the migration cycle?  Is it a combination of all these things?  We do know that their wintering habitat in Mexico is shrinking, due to illegal logging of the areas where they normally go.   In addition, there are fewer and fewer places for Monarchs to stop along the way.

Female Monarch
(Photo by Kenneth Dwain Harrelson
Courtesy of Wikimedia Commons)
 Monarch butterflies travel north at about 50-100 miles per day.  The butterflies don't make a single trip from Mexico to Minnesota.  Instead, they breed along the way, then their offspring continue the journey.  It take 3 or four generations for them to reach Minnesota from Mexico.  In other words, they travel in stages, as spring moves northward and flowers become available for nectaring and Milkweed plants for breeding.  You can read more about the migration and see a map at this site:

Only once in my life have I seen a migrating flock passing through Minnesota.   It was many years ago, when I was still in college.  A fellow student and I were driving along a back country road when the call of nature came, so we pulled over and I  went into the woods to pee.  Suddenly I was surrounded by fluttering Monarchs.  There must have been three or four hundred of them.  It was a magical moment I will never forget.  I called to my buddy to come see, and he was amazed, too.   Of course, I didn't have a camera with me (I never seem to at these moments) so the only record of this event is in my memory - and I don't even remember exactly where it was.  But I'll never forget the wonder of it!

Even if I could remember the place, I'm not sure that patch of woods still exists.  The land is becoming more and more developed along the migration route, with fewer "way stations" for the butterflies to breed and feed.   So one way you can help the Monarchs is to plant milkweed for them.  Each fall, I harvest the milkweed seeds on my land and sell them in my eBay store, The Happy Rooster, for butterfly gardeners.   I have both the Common Milkweed and what I call Swamp Milkweed, the Aesclapia species with the narrower leaves that likes ditches and other damp areas.  I do a pretty good business with this, since commercial seed companies don't offer such "weeds" in their catalogs.  In this way, I am doing my little bit to help Monarchs survive.  You can do the same:  Be a good Monarch steward and plant some milkweed in your butterfly garden this fall -- help save our state butterfly.