“Butterflies fill the air”: A Guest Blog From the Monarch Reserve in Mexico


The following is a guest blog post by Margaret Hsieh, an attorney in NRDC's New York office.

Female monarch in Cerro Pelón portion of the Monarch Butterfly Biosphere Reserve. Photo credit: Margaret Hsieh.

High in the Sierra Madre mountains of Mexico, complete stillness seems to reign at first. The woods are tranquil, worlds apart from the hustle and bustle of the town where I've been based. As I adjust to the surrounding serenity, however, I start to notice movement all around me. At first it is imperceptible, but then it becomes unmistakable: the entire area is palpitating with the beating of thousands of butterfly wings.

I was in the Cerro Pelón portion of the Monarch Butterfly Biosphere Reserve, helping to monitor the remaining population of North American monarch butterflies that overwinters in Mexico each winter. Since mid-January, I accompanied staff from the World Wildlife Fund, Danaidas, and the National Commission of Natural Protected Areas (CONANP) to different portions of the reserve and beyond, to monitor and count the monarch colonies inhabiting each area.


Colony of monarchs hanging from oyamel fir branch in Cerro Pelón portion of the Monarch Butterfly Biosphere Reserve. Photo credit: Margaret Hsieh.

The monarchs are a wonder to behold. On cold days, dense groups of butterflies hang immobile from oyamel fir and pine trees, like immense chandeliers that have sprouted bizarre and magnificent scales. But on warm days, countless monarchs descend from their roosts in search of nectar. Butterflies fill the air, carpet the ground, and alight on flowers, leaves, and branches. Those high in the sky appear as brilliant specks of orange and black, like intricately patterned confetti fluttering in the sunshine.


The monarch is a remarkable species that journeys over 2,500 miles across the North American continent annually. It takes four to five generations of butterflies to complete a single migratory cycle from Mexico to Canada and back. No butterfly that arrives in Mexico has ever been there before. Yet, somehow, the monarchs return to the same mountaintops every year.

The monarch's spectacular migration has evolved over thousands of years. Yet, within just two decades, human activity has put this phenomenon in danger, wreaking a dramatic decline of over ninety percent in the migrating monarch population. The population has been devastated by a combination of deforestation in its winter habitat, climate change, and—above all—by the pervasive use of glyphosate-containing herbicides in the United States, which has decimated the milkweed on which monarchs depend. Just last week, Mexican authorities released data indicating that monarch numbers from this year are the second lowest ever: approximately 56.5 million butterflies compared to over a billion individuals in 1997.

Although there has been a clear downward progression in monarch numbers, this decline is not inevitable. The Mexican experience provides a striking example of how forceful and concerted action can counter destruction of the butterflies' habitat. In the past, illegal logging was a key threat to the monarch reserve. Responding to this crisis, the Mexican government strengthened its enforcement efforts. Just as importantly, the government, NGOs, and private entities have collaborated to provide funding and support to local communities to develop alternative, non-timber-based sources of income. Revenue from activities such as tourism, reforestation, sale of handicrafts, and production of edible mushrooms in greenhouses has taken significant pressure off the forests inhabited by monarchs. Although small-scale logging remains a problem, large-scale logging in these forests all but ceased by 2012.


Nursery where oyamel fir and pine are being grown for restoration of the monarch's wintering habitat. Photo credit: Margaret Hsieh.

The progress in Mexico is inspiring but cannot, on its own, reverse the monarch's decline. Success in conservation of the butterflies' winter habitat in Mexico stands in sharp contrast to the ongoing, large-scale destruction of the butterflies' milkweed habitat in the United States. With the adoption of genetically modified crops that are resistant to glyphosate (also known as Roundup), the corresponding increase in use of the herbicide has led to widespread destruction of milkweed throughout the agricultural Midwest—a key breeding ground for monarchs in the United States.

We don't have to choose between monarchs and food production. Prior to the widespread use of glyphosate, milkweed grew, and monarchs thrived, alongside crops in agricultural fields. However, we do need to fight back against Big Ag interests in maximizing profits through ever-increasing pesticide sales. Last February, NRDC petitioned the U.S. Environmental Protection Agency (EPA) to review glyphosate in light of serious harm to monarchs; NRDC also challenged EPA's approval of a new, glyphosate-containing pesticide called Enlist Duo. By scaling back excessive use of pesticides and planting more milkweed, we will not only help to safeguard monarchs, but will also pave the way for more productive farms and healthier communities.


Seeing the monarchs this winter has been a life-changing experience. But I hope it is not a once-in-a-lifetime experience. With luck—and lots of effort by involved citizens in both countries—the monarch's extraordinary migration will be around for many years to come.


Monarch in the Piedra Herrada Sanctuary. Photo credit: Margaret Hsieh.