Butterfly phenomena in northern Ohio was a sight to behold
A perfect storm of weather and season combined Sept. 9 to create an amazing natural phenomenon – the “stacking up” of hundreds of thousands of migrating monarch butterflies, which huddled in woody shelters from Cleveland to near Toledo along Lake Erie’s south shore.
The weather-storm was the remnant of Tropical Storm Gordon, which stalled over the Midwest to cause a howling gale-force nor’easter to roar across central and western Lake Erie. The strong east-northeast winds generated by the low-pressure system blew a steady 25 mph, gusting to nearly 40, and the gales came right when hundreds of thousands of monarchs were migrating southwest across the lake.
One can only wonder how many monarchs perished in the lake-crossing, haplessly caught in downdrafts that splashed them into the waves. Nature takes no prisoners.
Each September into early October, the well-known migrant population of monarchs – sexually immature individuals known as travelers – leaves northerly latitudes of eastern North America, bound 1,500 miles or more for the oyamel fir forests of the Sierra Madre Mountains of central Mexico. There, this special “traveler” generation of these big, stout butterflies clusters en masse for the winter. They do not sexually mature until spring thaw before mating and heading back north.
The ensuing generation, incredibly, emerges and resumes migration; it, too, at least once may regenerate before reaching Ohio and more northerly Canadian locales. How these butterflies “know” how to return to their ancestral home grounds with no firsthand knowledge is a mystery. These are insects with brains the size of a pinhead.
On Sept. 9, naturalists’ social media offerings were alive with sightings, photographs, and videos from Whiskey Island, a rare tiny wooded shelter at the mouth of the Cuyahoga River in downtown Cleveland, to Kelleys Island in western Lake Erie off Marblehead Peninsula to the sprawling Ottawa National Wildlife Refuge 15 miles east of Toledo.
Visual evidence of the event was stunning. Uncountable numbers of the familiar, orange-and-black butterflies appeared in one media posting after another. As Sept. 9 progressed, it was clear that this was a passing natural phenomenon and not to be missed. I live about 15 miles of Ottawa NWR and drove up in the rain and gale to witness it. True. Amazing. An appropriate happening to use the often abused adjective “awesome.”
Equally amazing, in the calm of the morning of Sept. 10, the clusters of storm-battered monarchs evaporated as if they never occurred. Perhaps the butterflies quickly left to seek more food, flower nectar, and replenish energy as soon as the wind subsided and daylight returned. Or maybe they were driven by the unstoppable migration urge. In any case, they mostly were gone.
It is impossible, of course, to know just how many thousands of monarchs festooned cottonwoods, willows, gray dogwood shrubs, and arborvitae plantings, among other woody-plant hideaways. But I saw hordes of monarchs in all. It was a wow moment.
An afterthought: Do not think, given this report, that the migrant population of monarchs, seemingly suddenly so numerous, is “out of the woods.” It is not, not at all. It remains hard-pressed to survive long-term because of logging in the winter sites in Mexico, which fragment the forests and cause their “warm” interiors to freeze and kill monarchs.
And that is just part of the problem. Northbound spring monarchs face greatly diminished habitat. They must have milkweed plants on which to lay eggs and for the emergent caterpillars to feed. But milkweed across eastern North America’s Farm Belt has been devastated by profligate use of herbicides and pesticides by industrial farm monocultures, conversion of pasture and grasslands and prairie, and by incessant and unnecessary mowing of what little other habitat remains, such as along highways and road rights-of-way.
In addition, one good year of reproduction means nothing in the boom-and-bust insect world, even when living conditions are undisturbed. Weather itself in a given year can make or break a population. It is the long-term trends that matter, and migrating monarchs are still losing.
Yes, resident non-migrating populations of these popular, colorful insects exist in Florida and the coastal Southeast, perhaps Louisiana, and west of the Rockies on California’s Pacific Coast. So the species likely is not going away. But the mystery of these marvelous migrants – their lifeways perhaps once impacted by the Ice Age and retreat of the glaciers — may remain unsolved if they disappear before science can unravel their mystery. Note that we did not even know where they migrated to each fall until the mid-1970s. And their numbers were much stronger then. Wish the survivors well.