Butterflies feature in the carvings and friezes uncovered in the ancient Mesoamerican cities. Cultural myth honours them as a symbol of transformation. The Aztecs believed them to be the spirits of dead relatives, returning to assure them all was well. In Aztec lore the butterflies circled the bouquets of flowers carried by men of social rank. The perfume of such bouquets was always appreciated from the sides, the tops being reserved for the souls of the dead. Had the Aztecs ever stood on Cerro Pelón, as the autumn winds ushered in the change of season, I imagine they might have been overwhelmed by the sheer volume of spirits fluttering in from the north, for the beginning of November marks the month in the calendar when the Monarch butterfly arrives in the mountains to the west of Mexico City, following a 4,500 kilometres migration from the Great Lakes region of Canada and the USA. There is something poignant in the timing of their arrival, coinciding with Mexico’s celebration of the Day of the Dead (Dia de Muertos), when families and friends gather to remember their loved ones who have since moved on. It seems inconceivable that this small creature can travel such enormous distances. What confounds the scientists even more is how they know to return to the same place every winter, particularly as the returning butterflies are the third generation of the ones who left Cerro Pelón the previous spring. I’ve never given much thought to the butterfly beyond its obvious beauty; it seems such a cruel fate to be skewered with a pin and placed in a cabinet to gather dust. As February moves to March the butterflies are beginning to mate, already thinking about heading out on the long journey north. Before too long the millions of fiery wings weighing the branches of the oyamel fir trees will be gone. We feel the opportunity to witness such a spectacular gathering of butterflies is not to be missed. It’s time to take a closer look.
Emilio, our guide, has the look of a pirate. His smile suggests the quality of dentistry in the hillside village of Macheros, where our trek begins, verges on the grim. ‘Vamos!’ he calls, the moment Christine and I have slung our legs over our wiry ponies. The reins in my hands are made of frayed rope and light chain link; my shoes barely fit the stirrups. The track to the butterfly reserve is steep and peaks at 3,000 metres, good enough reason to let a horse do all the work. A chico trots along beside us, his role not entirely clear until we reach the more vertiginous heights, when I’m thankful he takes a firm grip on the lead rein, just at the moment my pony thinks he’ll take flight at the approach of some descending horses. For most of the climb thick clouds blot the sun – this is not a good sign. We need the warmth of the sun if we are to experience the butterflies in flight. Too cold and they will remain huddled together on the branches of the trees. After more than an hour’s scramble the track levels and we come across a half dozen ponies tethered to the pine trees: time to slip from the saddle and stretch those creaking knees. Emilio points ahead along the track, to a clearing where tourists huddle, studiously focusing their cameras on the thick forest. Monarchs flutter around my head and shoulders as I amble up the track. I let my gaze wander across the clearing, to where the branches of the trees appear to be sagging under the weight of their autumn leaves, only… Quickly I realize what I’m looking at: those autumn leaves are thousands upon thousands of monarch butterflies. The air is cool for the time being, though the breaks in the clouds are widening. Within ten minutes sunlight floods the forest. On the branches of the oyamel trees dormant wings start to flutter, tiny flames rippling through the forest. The temperature rises, the sun’s warmth penetrating the forest floor. Among the few standing in the clearing there is an expectant hush. Cameras are raised. Not long now. And then, sufficiently enlivened by the heat, the butterflies burst into flight. Like russet-coloured leaves buffeted by the wind they rise and fall, circling, filling the sky. It is the noise of their wings, though, that will remain in the memory: the collective beat of their wings comes as a soft hiss, the sound of a breeze whispering in the trees. An employee of the sanctuary tells us, ‘Soon the pregnant females will fly north, to south-eastern USA, where they will lay their eggs in milkweed. These eggs hatch into caterpillars that feed on the milkweed, becoming cocoons and emerging in late May as butterflies. These new butterflies will fly to the Great Lakes of Canada and the US, where they will breed again. By mid-August another generation will be born. But they don’t like the cold winter up there, so they will make the journey to these forests in Mexico, where the winter is milder.’ Some researchers believe the monarchs preserve their energy in flight by gliding on air currents as they travel south, though much like the mystery surrounding the butterflies ability to find the same winter habitat year in year out, little is known about how such small organisms travel so far.
Fred Urquhart’s childhood passion was butterflies. During his school days in Canada he studied all the books and papers written on the subject. His time out of school was spent in the marshes and the meadows, observing, noting, wondering: where do monarch butterflies go in winter? By 1937 Urquhart was making his first attempts at marking the butterflies wings, so that he might later track them, though his early efforts met with little success. By the late 1940s he and his wife Norah had developed a successful system of tagging the wings, affixing tiny labels reading, “SEND TO ZOOLOGY UNIVERSITY OF TORONTO CANADA”. In 1952 he appealed to volunteers to assist with the tagging and over the next 20 years thousands of enthusiasts became involved. Ken and Cathy Brugger of Mexico City heeded Urquhart’s call for help. During a period of two years they travelled back and forth through the mountainous region of Michoacan, west of Mexico City. In January 1975 their efforts paid off. They sent a note to Urquhart telling him they had discovered a sizeable colony of monarch butterflies at 10,000 feet, on the summit of a remote range of mountains. Enthralled by such news, a year later Urquhart made his own visit to the region. Within five minutes of arriving at the site of the Brugger’s discovery he found a monarch with the tag PS 397, released by two schoolboys and their teacher from Chasks, Minnesota in early August 1975. This particular monarch had travelled 2000 miles in two months. Now Urquhart could finally answer his childhood question of where the monarchs went in winter. Whilst habitat destruction and pesticides have seriously reduced the monarch population, the Aztecs, had the Spaniards not wiped them out, would have been able to rest easy on Cerro Pelón: for the time being the spirits of the dead will continue returning to the forests of Michoacan.