The air is crisp in autumn. Daylight dwindles. Colors fade into soft shades of earth. Animals gather and store food. Southerners unpack chili recipes, sweaters and boots. Even without the calendar’s glaring reminder, the change of season is evident, and it signals an inexplicable inclination to prepare for colder months. But as October and the desire to roost set in, one creature in particular is busier than ever to get out.
By the time cooler temperatures kiss the Gulf, the Eastern monarch butterfly is already halfway through its 2,500-mile journey, headed to a place it has never seen before. It’s this instinctual migration, from as far north as Canada to the isolated mountaintops of Mexico and back, that makes it one of the most studied insects.
Of the roughly 17,500 butterfly species, the monarch is also among the most recognizable, with its orange-red wings laced with black lines and edges speckled with white dots. The distinctive colors draw attention from even the most wandering eye as it flutters among flowers and grasslands. To predators, such as birds, however, the bright hues serve as a warning: monarchs are poisonous, thanks to their diet of milkweed. These butterflies have evolved to tolerate the toxic wildflower and to use the toxins to their advantage. The defense is so clever that, over time, viceroy butterflies became monarch imposters. The viceroy is nearly identical — enough to avoid being eaten — but it differs in three ways: it is smaller than a monarch, has a horizontal black line running across its hind wing and does not migrate.
Milkweed is the only leaf that will sustain a caterpillar
The monarch is the only known butterfly that makes a two-way migration, heading south for the winter and returning north in the spring. But, as with many things in nature, there are exceptions to the rule. Not all monarchs migrate — those found in Florida, stay in Florida year-round. Of those that do migrate, not all head to Mexico. Western monarchs, those found west of the Rockies, overwinter along the southern California coast. No matter the autumnal destination, however, the purpose is the same: finding a warm and humid place. It is all part of an incredibly orchestrated, genetic-level design, one that occurs annually and takes four generations to complete. The journey is fascinating, and it begins long before the first hint of fall. For the Eastern monarch, it’s a story that actually starts with an end.
The Circle of Life
With the coast’s first taste of spring comes millions of Eastern monarchs. They’ve spent the last five months overwintering deep within the forests of Michoacán, Mexico, and they are on the last leg of their return north. Having mated before leaving Mexico, the female has one last job to do and only one place it can be done. Before dying, each female will spend her final couple months searching for milkweed plants, on the leaves of which she will lay up to 500 eggs. From these eggs emerges the first generation of the monarch migration cycle.
This first generation will live about 30 days, all of which will be devoted to migrating north and reproducing. From these eggs the second generation is born, whose days are also numbered about a month and whose duties also include migrating and reproducing. How far north the second, and subsequently, third generations travel depends on a number of factors, including the availability of milkweed, local climate, geographic conditions and weather. About four months after the monarchs’ first spring sighting, the fourth and final generation completes its transformation from larva to chrysalis to monarch.
By now it is late summer, and the shorter days, cooler weather and angle of the sun awaken the butterfly’s instinct to begin its journey south. It is this generation, known as the “super generation,” that will complete the thousands-mile migration. It will head to a place it has never been, but it’s the same location, the very same Mexican forests, that Eastern monarchs have traveled to for centuries.
A Sight to See — and Hear
From October to March, millions of Eastern monarchs spend their time flitting through the forest canopy or clinging to oyamel fir trees located on the mountaintops of Mexico’s Trans-Volcanic Belt. To observe the sight, about 150,000 people visit the area annually. The Monarch Butterfly Biosphere Reserve and Santuario de la Mariposa Monarca el Rosario are two such places to witness the phenomenon. Teresa McCown, of Fairhope, still recalls with wonder her 2018 trip.
McCown had spent the morning traveling by bus from Mexico City to the sanctuary, horseback riding halfway up the mountain, and then walking the rest of the way — reaching an elevation of about 11,000 feet. “It was just an amazing, incredibly breathtaking experience,” she says, thinking back on being surrounded by millions of monarchs. “We were so in awe that everyone just wanted to be quiet.” The group would spend the next six hours watching the winged creatures. “Every hour looked different,” McCown continues. “The scene changed with the climate. It wound up being around 70 degrees that day, and the monarchs were just swarming against the blue sky.”
The weather in the reserve is perfect for monarchs — it’s humid, which prevents them from drying out, and it doesn’t get too cold for too long. The cooler temperatures slow the insects’ metabolism, conserving much needed energy for their eventual return north. If the air dips below 55 degrees, butterflies are unable to move. To stay warm, tens of thousands huddle together on trees’ bark and limbs, sometimes as many as five-deep. Although the weight of a single butterfly is featherlight, their combined heft can break branches.
Butterflies cannot fly in temperatures below 55 degrees
But when all is still and quiet and the sun’s rays warm the trees, an incredible thing happens. One by one the monarchs begin to rustle, releasing themselves from the trees and cascading down amongst the streams and floor below. Like their weight, the sound of only one butterfly is imperceptible, but the concert of millions of delicate wings flapping echoes like the whoosh of a waterfall.
“We were paralyzed with wonder,” Fairn Whatley, of Mobile, says, recalling the excitement of witnessing a “burst,” or rapid release of thousands of butterflies at once. “It was Mother Nature at her finest.” Mobilian Suzanne Damrich, also on the excursion with McCown and Whatley, likens the government-protected sanctuary to a cathedral, saying, “The sound of their angel-like wings was soothing, putting me in a very contemplative state.”
Although this overwintering site was only recently discovered and recognized — about 40 years ago — Eastern monarchs have been migrating here for centuries. Indigenous people, such as the Otomi, Mazahua and Purepechas communities, witnessed the annual flocking as early as the 13th century. Because the butterflies arrive around the time of the Mexican holiday Dia de los Muertos, or “Day of the Dead,” they were thought to be the souls of the deceased returning. “There is a cultural reverence among the Mexican people, one that I’ve not witnessed in the United States,” Whatley mentions of the silence that is required in the presence of monarchs.
A Life of Plight
When winter melts into spring and the calendar turns to mid-March, the monarch knows it is time once again to travel. The sap from oyamel firs, which is high in sugar and nutrients, coupled with months of energy conservation, provide the strength needed for the trek north. After mating, the Eastern monarch follows the same flyway that brought it to Mexico: up through central Texas and then east along the Gulf. This path is where the fourth and final extraordinary generation begins its terminal months, coasting on wind drifts during the day and resting at night. As another circle of life nears completion, the travel-weary female has one thing on her mind: searching for milkweed on which to lay her eggs. She knows this is the only plant her larvae will eat. If no milkweed is found, no eggs are laid. And without eggs, there are no new generations of monarchs.
The size of a butterfly egg is only 1/32 of an inch
Lack of milkweed is one factor at play in the monarch’s plight. Climate changes are another, as is illegal logging, specifically in areas around the reserve. In essence, this unlawful practice removes a layer of the forests’ “insulation,” exposing the roosting butterflies to extreme temperatures.
Despite numbers decreasing by the millions over the past decade, conservation efforts have kept monarch butterflies off the endangered species list — for now. Education is key, which is the goal of Damrich and Whatley’s short film, “The Mystical Migration of the Monarch,” available on YouTube. “It’s a gentle invitation back into the garden,” Damrich says of the award-winning movie the duo wrote, directed and produced.
She continues, “Our culture has gotten away from the garden, both metaphorically and literally. We’ve lost touch with the earth that supports us.” And the earth is able to sustain us because of pollinators like bees … and monarchs.
“It’s all about reciprocity,” Whatley says. “They help feed us. Do you have flowers feeding them?”
Damrich suggests planting native milkweed and nectar plants and limiting the use of pesticides when creating a butterfly garden. She adds, “Monarchs are the poster child for all pollinators. Whatever you do to restore their habitat, you’re restoring all pollinators’ habitats. Really, it’s going back to what we’ve known for generations.”
Our desire to care for the earth might sometimes lie in a stream of subconsciousness, much like our inexplicable inclination to meld with the seasons. But it is there, passed down over centuries, much like the monarch’s instinct, buried deep within its mitochondrial recesses, to migrate to the same forests and yards year after year.
“Butterflies come to my back yard annually,” McCown says, adding, “It’s been great for my grandchildren to watch, too.” And so continues the story for generations to come.