Every winter, millions of monarch butterflies make one of the most extraordinary journeys in the natural world, traveling up to 2,800 miles from Canada and the United States to cluster on oyamel fir trees in the mountains of central Mexico, their wings blanketing the forest in a sight unlike anything else on Earth. For years, that winter gathering had been shrinking at an alarming rate, and conservation groups grew increasingly worried the migration might one day stop altogether. This week brought the most encouraging news in nearly a decade: new data from WWF Mexico and the Mexican government show the monarch population grew by 64 percent this winter, with butterflies covering more than seven acres of forest compared to just over four acres the year before. It is the largest population recorded since 2018 and the second consecutive year of growth after a long and painful decline.
Researchers credit a combination of factors for the rebound, including less drought along the migration route, which meant more flowering plants to feed on during the journey south, and a wetter spring and summer that produced more eggs and larvae in the breeding grounds across the United States. Decades of effort to crack down on illegal logging in Mexico’s Monarch Butterfly Biosphere Reserve have also helped preserve the forest habitat the butterflies rely on for winter shelter. Scientists are careful to keep the good news in perspective, noting that monarchs once covered more than 45 acres of forest in a single winter in the late 1990s, and that models still estimate a meaningful risk of extinction for the species if larger threats go unaddressed. But for now, the orange tide is coming back, and advocates across three countries who have spent years planting milkweed, restoring habitat and tracking individual butterflies are celebrating a comeback they helped make possible.
Source: https://www.theguardian.com/world/2026/mar/20/mexico-monarch-butterfly-population-increases
