Just as they have for millennia, monarch butterflies left their summer homes and migrated south to Mexico’s Sierra Madre high elevation forests. They were first seen in northern Mexico on October 20th. Then thousands of monarchs flew another 700 miles south and arrived at El Rosario Sanctuary for Día de Muertos, once again gracing the celebration of villagers who see monarch butterflies as their ancestors’ souls returning to visit.
Unlike the past, however, we now wonder if the monarchs will arrive on time, in what abundance, and if their damaged overwintering sites will still protect them until March when these same butterflies who flew south travel north again. People in the monarch’s summer ranges west of the Rockies also wondered when the warm weather would end and cooler temperatures trigger migration south. Monarchs were seen in Cleveland during the first game of the World Series in late October and others were seen in Ontario Canada this week. None of these is likely to make it to Mexico. Yet it is these tiny insects who stitch together a North American habitat mosaic that extends for 3,000 miles.
Monarchs in El Rosario Sanctuary (photo by Luna sin estrellas)When the relatives of these monarchs, several generations past, left Mexico last March they had survived an unseasonal snow storm followed by high winds and cold rain that killed butterflies and toppled their roost trees. During the summer breeding season in the U.S. and southern Canada, conservationists examined the Monarch Butterfly Biosphere Reserve for storm and arson damage; considered re-opening a copper mine in the Biosphere; planted reforestation seedlings; finished new tourist facilities where locals can sell food and crafts; and made plans for additional protection of the habitat.
Local people, such as this woman at El Rosario, hand weave pine needle baskets. forest and butterfly lossesThe shocking winter storm damage to monarchs and their forests came just after Mexico had announced the largest over-wintering population in five years. Ten acres of monarchs reversed population declines of the past, although still far below the nearly 45 acres 20 years ago (the last few years had around 2.5 acres). My story Mexico’s monarchs mostly survive unusual cold storm so far reported initial estimates of habitat and butterfly losses from the snowstorm. The March snowfall came when monarchs had begun to move out of the clusters and migrate north. This exposes the butterflies to freezing. When the snow melts monarchs become saturated, losing body warmth and their ability to fly, thus making them more susceptible to predators.