Perhaps it would be best to just let the mystery be.
But I can’t.
How did all these migrating Monarchs find an organic clover field next to a stand of pines in central Ohio? It’s not as though they’ve always been doing it because the clover field hasn’t always been there, nor have the pines for that matter. Did one lone butterfly stumble across the location some years ago and then the word got out? Hum, the word got out, let me think about that for a “minute”.
A roving swarm didn’t descend on the area because Monarchs travel alone. They arrive one by one, so that’s not how the place was found. Is this particular location imprinted at birth like their ultimate destination in Mexico? What happens if one year the owner of the field decides, enough clover already, lets grow corn? A lot of butterflies would have to quickly come up with an alternate plan or die. Perhaps many more than we realize travel completely alone and never become part of such a large gathering. Wouldn’t that be a better survival strategy?
In the pines they bed down for the night in tight clusters with adjacent areas having few if any butterflies. Some authorities have suggested this may be to keep warm but unless they are moving their wings almost continually, or are very closely sandwiched together, it’s hard to understand where the heat is coming from. If it’s a cold night each butterfly could keep itself warm moving its wings, but any cold air circulated wouldn’t be much help to the guy next door.
We observed that when perched in a close group the butterflies seem to respond to external stimuli, such as another butterfly attempting to land, by opening and closing their wings. A number, but not all, participate in this synchronized wing movement across an area of three or four feet. How does that happen when the stimuli may only be close to one or two?
Unlike the non-migrating generations of butterflies seen throughout the summer that often can look rather tired, most seen on the recent Mid-September evening looked newly emerged and ready to continue their long journey to Mexico.
In their beauty, covering the pines with their blossoming presence, they truly are flowers that fly.
For more info on Monarchs: https://monarchjointventure.org/monarch-biology/monarch-migration