Every autumn, an incredible journey begins. The brisk northern wind tells tens of millions of monarch butterflies that it’s time to leave their feeding grounds in southern Ontario and Quebec, and the northeast U.S. The delicate insects follow the sun, tracing their way down North America. And then they funnel into Texas, bursting across the Hill Country and over Mexico’s Sierra Madre Oriental range, to land for the winter in the country’s lush oyamel fir forests. On wings made from scales as thin as tissue paper and softer than a scrap of silk, they fly nearly 5,000 kilometres – one of the longest migrations in the insect world. With only a sensory map to guide them, they arrive in this place they’ve never been and will never be again.
Their destination is the Monarch Butterfly Biosphere Reserve in central Mexico, which spans 56,259 hectares across the states of Michoacán and Mexico. Here, oyamel fir trees create a protective microclimate for the monarchs (mariposas monarcas in Spanish), the canopy acting as a blanket so the temperature doesn’t rise too high or drop too low. Much of the reserve – a protected area since 1986 and UNESCO World Heritage Site since 2008 – is closed to the public for conservation. But six sanctuaries, three in each state, give monarch chasers a window into this wondrous journey.
It’s an hour past sunrise, and I’m in a van heading out of Valle de Bravo, a resort town on the shores of Lake Avándaro, two hours west of Mexico City. Both Mexican and international tourists flock here for its paragliding, waterfall hikes, colonial architecture and the large swath of North America’s eastern population of monarchs that overwinters in the Piedra Herrada Sanctuary, just 45 minutes east. We wind our way through verdant forest, past houses tucked into the green mountains high above the lake. Cascades of purple and orange flowered vines tumble from curled iron gates. In the dust from the road and the morning sun, everything seems to glow and even the leaves on some of the trees look like butterfly wings in the right light.