A Long Way to Flutter By

Monarch Butterflies pause during their 3,000 mile migration


When you find yourself running low on energy; or maybe lost without a map, consider the Monarch butterfly, please.
Susan and I made the hour-long trip to Mentor Headlands State Park along Lake Erie’s shores this morning to bird the fall warbler migration. Along with the birds, we found ourselves in the midst of a massive Monarch butterfly movement as the insects moved from northern territories—by the thousands!—to their wintering grounds in the Transvolcanic Plateau region of Mexico. Depending on how you measure it, many of these half-gram insects will travel nearly 3,000 miles before they hibernate.
When you start reading about these butterflies you bump into all kinds of words you might not otherwise associate with light-weight insects. “Hibernate in caves,” for example. That’s what they do. Like bears and other hibernators (chipmunks and groundhogs come to mind) they slow their heartbeat and take a nap—like some of my retired friends.
The principal tree they like in Mexico is the Oyamel fir. We’ve been fortunate to see the hibernating Monarchs in this country near Santa Barbara, California, when they over winter in the Eucalyptus trees near Goleta.
Here, in northeast Ohio, we’re fortunate to see the bulk of migrating Monarchs from the eastern part of this country, and Canada, pass right through. Most of the insects move east of the Great Lakes then turn a southwesterly direction. When we get strong winds from the north, as we’ve had the past few days, the butterflies flutter by in prodigious numbers.
Today, thousands of them rested on trees throughout the park. I thought it interesting that of the larger fly catcher species we saw, Great-crested Flycatcher for example, no one was eating Monarchs. It was as if the birds and insects made a pact: We’re all in this migration boat together, so let’s all pull on the oars. Something like that.
It’s been estimated that about 300 million Monarchs head to Mexico for the winter. Theirs is not an easy life. If they don’t get eaten or whacked by a car along the route, there’s all kinds of stormy weather and loss of habitat to deal with once they get to Mexico.
Unlike migrating birds, the Monarchs have never travelled the route they will follow. Previous generations have died off before the journey begins. Many that start are more than three generations away from those that previously made the trip. Since its wintering grounds were discovered in the high mountains of Michoacan State west of Mexico City, scientists have studied how this critter with a tiny brain, migrates out of Mexico in the spring, moves up to its breeding areas where it produces several generations, then migrates back again to an area that the year’s last generation has never been to.
The exact purpose of their migration and their ability to make the trip at all, remains an intriguing subject for scientists studying them today. I don’t understand the mechanics or biology of the Monarchs’ movement, however, I do appreciate its beauty. Seeing them, by the thousands, is a bonus, maybe our reward, for getting out and birding.