One sunny fall day in West Texas when I was a foolish boy, I caught hundreds of monarch butterflies and released them in my sister’s bedroom, where they landed in great masses on her flowered curtains. The visual impact of this sight was not lost on my mother, who nonetheless threatened to tan my hide if I didn’t release every one to the outside world. After opening the window and removing the screen, we watched the butterflies wing their way south. Where in the world, we wondered, were they going?
Thirty years later, I found out. As I stood atop a mountain at the El Roasrio butterfly preserve near Angangueo, Michoacán, Mexico, a dozen monarchs landed on my jacket and hat, and for a moment I looked like those flowered curtains. Then there was a sudden rustle in the tree above, followed by an explosion of orange and black, as thousands of butterflies took flight in the warming rays of the morning sun. All around me giant fir trees were covered with so many hundreds of thousands of butterflies that no green could be seen on the branches bending toward the ground. Everywhere I turned were butterflies and more butterflies. I gasped to catch my breath—not from the steep climb or the 10,000-foot elevation but from the exhilaration of seeing so much natural beauty.
Each winter more than 100 million monarch butterflies (as many as 4 million per acre) gather at overwintering sites in and around Michoacán, just a three-hour drive from Mexico City. El Rosario is one of several preserves owned by the Mexican government and the only one open to the public. If you have a long weekend to spare and want to experience the beauty that I did, make your travel plans now. The best time to see the monarchs is from mid-February to mid-March, when they mass in their densest congregations. Depending on when you go, you may even get to see their spectacular mating flight, as pairs couple in midair, the female’s wings folded as she dangles beneath the soaring male.
By the end of March, the butterflies depart on their journey north, fanning out over the eastern two thirds of the United States, from the slopes of the Rocky Mountains to the canyons of Wall Street and on into Canada. They follow a bountiful feast of flowers for distances hard to imagine. A hundred miles per day is not uncommon, even for these typically frail creatures; one tagged monarch once covered 286 miles in a 24-hour period. Along the way the females lay their eggs, primarily on milkweed plants, which provide a source of food for the rapidly growing caterpillar larvae. About a month later, a fully developed monarch emerges from its chrysalis and continues the migration. Before shorter days and cooler weather send the butterflies hurrying south again, three to five generations are born—a miraculous reproductive process that has been repeated annually for perhaps 40,000 years. Why do they always return to Mexico with such pinpoint accuracy? There is no proven scientific explanation, but one theory has it that the monarchs, like some birds, are sensitive to magnetism; thus they are attracted to the mountains there, which have large iron ore deposits.
Before you go, you might sign on with one of several package tours that serve the area, but you don’t have to: I found it a surprisingly easy trip to make on my own. I flew from San Antonio to Mexico City, where I rented a car and headed west on Highway 15. On the way into Toluca, I stopped to look at the huge statue of revolutionary hero Emiliano Zapata astride a mountainous bronze horse, then took the bypass around the south side of the city. (An argument for driving through Toluca is that you’ll get to stop at Casa de las Artesanias, or CasArt, a fine government-run crafts shop that has reasonably priced high-quality goods from all over the country. On Fridays, the city also has a crowded but colorful Indian market.) From Toluca, it was a beautiful one-hour drive through wooded mountains to Zitácuaro, a town of 67,000—though whether that number refers to people or speed bumps is anyone’s guess. Ten miles west of Zitácuaro, near the new Villa Monarca Inn, I took the well-marked right-hand turn up the flower-covered Angangueo valley to the mountain towns of Ocampo and Angangueo. Both towns are at the base of the El Rosario preserve, known officially as the Reserva Mariposa Monarca Santuario Sierra el Campanario.
The existence of this and other preserves is in part because of the work of the Mexican conservation group Monarca A.C. In 1986, reacting to extensive logging, Monarca prodded the government to ban all development in an area of 11,000 acres, to create more than 28,000 acres of buffer zones (with partial agricultural restrictions), and to purchase outright 2,000 acres of prime overwintering sites. These moves haven’t had exclusively positive consequences: In an effort to save the butterflies’ natural habitat, the conservationists displaced some jobs. But alternate sources of income for local residents have been found in such areas as farming and commercial chrysanthemum growing. Tourism has also been a money-maker; last year, 48,000 people paid ten pesos each (about $3) to visit El Rosario. “There’s no solid evidence that tourists are harmful to the monarchs,” says William Calvert, an Austin lepidopterist who discovered many of the overwintering sites in the mid-seventies. “It is habitat destruction that harms them.”
I chose to stay in the mining town of Angangueo—the heart of butterfly country—at the Hotel Don Bruno. The hotel was nearly full with an IMAX film crew, and no one wanted to talk about anything but monarchs. IMAX is a special camera process that uses 65mm film and a print ten times the size of regular 35mm film. Cinematographer Alex Phillips, who had done camera work on many movies for legendary director John Huston, told me he had shots of butterflies that would fill an entire 65-by 90-foot screen. “The movie is