National Geographic News: NATIONALGEOGRAPHIC.COM/NEWS
 

 

In the Midst of Monarchs: Mexico's Butterfly Oasis

Ben Harder
for National Geographic News
June 10, 2003
 
Of all the churches I saw in Mexico, the forest of Sierra Chincua was
most cathedral-like.

Its many-storied firs, each standing as slender and erect as the supports of a Gothic arch, rose gracefully skyward. Beneath them, I felt dwarfed and awed, the way a worshipper might in the nave of Mexico City's Basilica de Guadelupe.


My friend Marc and I had left the capital just that morning and driven to these volcanic highlands in the central state of Michoacan. Now we found ourselves at an elevation of 10,000 feet (3,000 meters), working to keep pace with our guide, Gilberto, who led the way along a path that hugged the forested hillside.

As we penetrated more deeply into the forest, Gilberto told us—repeatedly—of the pains that he and others took to maintain its oyamel firs.

"He keeps saying how they plant saplings during the off-season," Marc translated. "It seems really important to him—because he's really hammering the point home."

There's good reason for Gilberto's fixation with the trees. They support the butterflies. And the butterflies support him.

The butterflies of Sierra Chincua, or Chincua Hill, are monarchs. The flitting, orange-yellow-and-black insects found over much of the United States during summer months. In winter, nearly all North American members of the species congregate in a tiny region of Michoacan.

Each September, 100 million or more young monarchs begin the journey south. A couple of months and several thousand miles later, they home in on central Michoacan's oyamel forests. Here they and their progeny stay all winter, moving only slightly to change elevation as temperatures change.

In late February, the monarchs display a burst of reproductive passion. Impregnated females then depart for the north. The males die here.

Scientists believe that the monarchs have been repeating this cycle—and making their annual pilgrimage to Sierra Chincua and a handful of neighboring hills—for thousands of years.

The miracle of the monarchs' migration lies not only in the distance that the fragile animals cover, but also in the fact that no single butterfly knows the way from experience. Their lives span only a few months each, so the individuals that make the journey to Mexico are several generations removed from those who last left it.

To find their way back to their ancestral home, the monarchs use an internal compass set by the position of the sun in the sky. Scientists at the University of Massachusetts have recently discovered that the butterflies also use the sun to set circadian clocks that they need to properly orient themselves for their transit.

Speaking for the Trees

The monarch is choosy about its habitat. The oyamel firs have held their ground on these volcanic hillsides for eons, and Mexico-bound monarchs will spend the winter nowhere else.

Recently, deforestation brought on by logging has thinned the forests—and jeopardized the butterflies, despite their numerical strength. So the Mexican government in 1986 created the Monarch Butterfly Special Biosphere Reserve, which consists of five hilltops on which the monarchs remain for the winter. Three hills have been set aside completely as nature preserves.

Sierra Chincua is the newer of two sanctuaries, out of the five, that are open to the public. Jobs such as Gilberto's provide important sources of winter income for local people, many of them farmers who might otherwise venture into the U.S. to work as migrant farm laborers.

Gilberto has worked as a guide in Sierra Chincua for all seven years that it has been open to visitors, and the fee and tips that he earns gives him an incentive to see the monarchs' habitat preserved.

But logging, though now illegal in the reserve, persists. Hence Gilberto's concerned refrain about planting trees.

In halting Spanish, I asked him about the management of the forest. In reply, he pointed to trees that had been cut down after suffering damage from lightning, and to saplings that he and other guides had planted the previous rainy season, after the butterflies and tourists had left.

Stained Glass Menagerie

In the shade of the firs, dabs of floral color dotted the forest floor. Gilberto recited the names and properties of the flowers to me as we passed them: the little red mirtos, shaped like miniscule chili peppers; the brilliant trabanillos, in violet and yellow varieties; the orange-red lemoncillos, which produce drinkable nectar; and the anemone-like buds of the sanequa, which have medicinal properties.

But the colorful flora of the forest was only a prelude to its greater artistry, its stained glass.

Our trail suddenly joined a broader one, and we saw Marc's mother, his cousin, and three family friends up ahead. All had driven with us from Mexico City that day, but had elected to ride horses into the reserve by a different route than Marc, Gilberto, and I had taken.

On foot to minimize the amount of dust kicked up, our party approached the trail's end, where Gilberto told us the monarchs awaited. At first, a few could be seen here and there in the air. Then larger numbers—on bushes, trees. Up ahead, I realized, butterflies littered the ground like a carpet.

A few ginger steps onward, I found myself in the midst of a monarch mass. A dull orange throng clogged the forest's vertical pews.

A few butterflies flitted from one tree to the next, and late afternoon sun illuminated their orange wings. Had we arrived earlier in the afternoon, Gilberto said, the monarchs would have been more active. But since our drive from Mexico City had taken longer than we'd expected, I contented myself with watching them rest, like weary pilgrims at the end of a journey.

But as I tiptoed quietly back up the trail and away from the majestic monarchs, I couldn't help wondering whether I was perhaps more the pilgrim than they.
 

© 1996-2008 National Geographic Society. All rights reserved.