A Monarch Migration Timed to Mexico’s Day of the Dead
In Mexico, where monarchs end their migration around Day of the Dead, or Día de los Muertos, the butterflies symbolize departed loved ones and hope for conservation success
- By Christin Parcerisa // Photos by Jaime Rojo
- Conservation
- Sep 26, 2024
Huddling for warmth before sunset, monarchs cover oyamel fir and pine trees at Sanctuary El Rosario in Michoacán, Mexico, part of the Monarch Butterfly Biosphere Reserve.
AMONG SOME PRE-HISPANIC CULTURES whose descendants still reside in modern-day Mexico, there’s a powerful link between monarchs—the beloved butterflies whose southern migration ends in South-Central Mexico around Día de los Muertos, or Day of the Dead, each year—and the wing-thin veil between the living and the departed.
The nature of that relationship has changed over millennia, as religious beliefs and cultural practices have merged in a largely unwritten history passed down through stories and traditions. The insects’ migration has altered, too, due to factors including climate change and habitat loss and fragmentation—particularly the displacement of milkweed-rich native grasslands across the Midwest by industrial agriculture.
And yet, the bond remains: both a glorious cause for celebration and a fragile occasion for conservation success.
Angling for a spot on a crowded oyamel tree, a latecomer joins its fellow insects in the Monarch Butterfly Biosphere Reserve.
A blanket of beauty
Millions of monarchs depart breeding grounds east of the Rocky Mountains in southern Canada and the northern United States every fall en route to the Mexican states of Michoacán and México. The migration, stretching up to 3,000 miles, takes just a couple of months.
By late October, monarchs begin alighting in the mixed pine and oyamel—or sacred fir—forest, where they’ll overwinter before returning north, typically in March. These monarchs are not the same ones that visited the year before. It’s always a new group, with each migrating generation’s life-span lasting about 9 months. (Nonmigrating monarchs live 2 to 6 weeks.) Yet each population knows the way, using air currents to reach their destination as efficiently as possible.
In recent decades, monarch iconography increasingly has shown up in Day of the Dead celebrations across Mexico, as with this young woman dressed as a butterfly for a student parade in Zitácuaro, Michoacán.
And what a destination it is. Perched on hillsides nearly 2 miles above sea level, the forest fosters a unique microclimate with winter temperatures between 32 and 59 degrees F: warm enough to maintain the monarchs’ fat reserves and humid enough to prevent their delicate bodies from drying out. “The forest acts somewhat like an insulating blanket and provides a buffering effect to temperature changes,” says Ernest Williams of the Monarch Butterfly Fund.
A member of the Mazahua people decorates the graves of his relatives for Day of the Dead on the Francisco Serrato communal farm in Michoacán. The Mazahua believe monarchs are the souls of their ancestors.
Something else helps keep them warm: body heat, with monarchs covering the trees, thousands to a single branch. While each butterfly weighs less than a gram, the combined effect requires a sturdy tree. Oyamels can grow nearly 200 feet tall, with trunks more than 6 feet in diameter.
It’s precious habitat, which led to its protection. In 2000, with the support of the Mexican government, 139,019 acres were designated as the Monarch Butterfly Biosphere Reserve, bordering four municipalities in the state of México and six in Michoacán—land some consider sacred ground.
In a common Day of the Dead tradition, families create altars for deceased loved ones, often featuring candles and incense, sometimes with representations of monarchs. One educator from Michoacán, Estela Romero, created an altar for monarchs that died in a 2002 snowstorm. Climate change is impacting the scale and timing of monarch migrations both south and north.
Life and death in every flutter
Mexican lore holds that, once a year—November 1 for children, November 2 for adults—the souls of the dead may return from the afterlife. The living invite their deceased loved ones home to celebrate by creating ofrendas, or altars, laden with favorite foods, photos, candles, flowers and incense.
The timing of the monarchs’ arrival in Mexico likely solidified an association with life-and-death cycles. “The representation and influence of butterflies have been significant in various traditional beliefs of Indigenous communities in Mexico, as well as in other ancient societies worldwide,” says Rebeca Quiñonez-Piñón, monarch recovery strategist for the National Wildlife Federation. Pre-Hispanic cultures venerated butterflies, she says, with Aztecs believing butterflies to be the souls of warriors who perished in battle.
Legends from other Indigenous communities, such as the Purépecha and Mazahua in Michoacán, vary. Some see butterflies as incarnations of lost friends and relations, while others tell of deceased relatives riding on butterfly wings to reach families’ altars. Many people light candles and burn copal, an aromatic tree resin, to act as landing signals for the monarchs—that is, their loved ones’ souls.
Butterflies stream through El Rosario, a sanctuary within the biosphere reserve, in February 2023.
Diego González, a certified guide at the Sierra Chincua Monarch Butterfly Sanctuary within the biosphere reserve, says monarchs have long been part of the identity of the people of Michoacán, both prior to colonization and in the present day. “Before calling them monarchs, these butterflies were known as harvesters (cosechadoras) or as the sun’s brides (las novias del sol),” he says.
The connection to monarchs remains today, even as the significance behind it has evolved. González, like many of his fellow guides, performs a private ritual before leading tours into the forest—a sort of spiritual request for permission to enter. He sees the forest not only as a boundary between the living and the dead but as a real-world touch point. Eastern Michoacán marks the border of two ethnic groups: “On the Michoacán side, we speak the Otomí dialect, and on the side of the State of Mexico, they speak the Mazahua dialect,” González says. Although the two groups have their own languages, customs and culture, both treasure the monarchs. “This place is known as the meeting of two worlds.”
Forested areas adjacent to the Monarch Butterfly Biosphere Reserve are vulnerable to logging, some of it illegal.
Forecasting future flights
Preserving that special place comes with ever-evolving challenges, from climate change to habitat loss and fragmentation across North America to illegal logging near the reserve.
Since the winter of 1995-96, when monarchs occupied more than 45 acres of the reserve, that acreage has shrunk—some years in a drastic way. In 2014, monarchs occupied only 1.6 acres; years since have seen steady decline. Between 2019 and 2023, the average overwintering population hit only about a third of scientists’ recovery target. “These persistently low population figures are a significant warning sign that should not be underestimated,” Quiñonez-Piñón says.
To protect the habitat and to help support surrounding communities, the Mexican nonprofit Alternare has provided job and conservation training for two decades, including reforestation projects on communal lands known as Macho de Agua.
She explains that climate change has disturbed the monarchs’ seasonal biological clock, confusing when they should migrate and when they should stay in place and breed. Native milkweed’s blooming and dormant times also have been affected. With food and host plants available later in the year, more monarchs are ending their fall migration in the southern United States rather than venturing farther south.
Williams cites increasingly severe storms as another factor that “can exert quite an effect on the overwintering colonies,” he says. Also, “those places on the mountaintops where they’re overwintering now are becoming warmer. So, maybe they need to go higher up a mountain.” To that end, the Monarch Butterfly Fund is supporting research into planting oyamels at elevations higher than the trees’ historical range.
Ecotourism brings butterfly lovers and employment to the region. In 2023, 60,000 people visited the reserve—a significant number given that one of the Michoacán host municipalities, Zitácuaro, has fewer than 200,000 residents.
“If the migration collapsed, then we’d lose a lot of the beauty of what we have with living things,” Williams says. “Monarchs are good representatives of the beauty and diversity of nature, and that’s something we need to take care of.”
Quiñonez-Piñón agrees, underscoring that the reserve allows visitors to witness and admire “the resilience of this little insect to all the challenges it faces. It teaches so much about appreciating life and doing everything it takes to survive and make sure that future generations survive as well.”
NWF priority
Acts of Service
In December 2024, the U.S. Fish and Wildlife Service will unveil its final listing decision on whether to protect the migratory monarch under the Endangered Species Act, representing a significant step in conservation efforts. NWF is ready to amplify its ongoing initiatives to conserve this one-of-a-kind species, ensuring that future generations can find inspiration in its beauty and resilience. Together, we can foster hope for a sustainable future. Learn more about NWF’s Monarch Recovery Strategy.
Christin Parcerisa is a writer and editor living in Mexico City. Read more about photographer Jaime Rojo.
More from National Wildlife magazine and the National Wildlife Federation:
Pollinator Gardens Bring Monarchs—and Joy—to a Texas Town »
Peril at Journey’s End »
Blog: Day of the Dead and Monarch Conservation »
Recurso en español: Crea un Jardín Sostenible Que Ayude a la Vida Silvestre
