New reports bring hope for eastern migratory monarch butterflies

MEXICO CITY, Mexico (18 March 2026) - WWF-Mexico and its partners today released two new reports highlighting improvements to the population and winter habitat of the eastern migratory monarch butterfly. Together, they mark a hopeful year for the species, with one estimating an increase in the species’ population, and the second highlighting decreased forest degradation in the areas where most monarchs cluster in colonies during the winter.

According to the survey, Forest Area Occupied by Monarch Butterflies Colonies in Mexico During the 2025-2026 Hibernation Season, scientists found a 64% increase of monarchs during this period. Monarchs occupied 7.24 acres of forest compared to 4.42 acres the previous winter in their hibernation grounds in Mexico. The annual WWF-Mexico-led survey measures the area of forest where monarchs establish their colonies to hibernate each winter, providing a scientifically robust indicator of their population status.

A second report, Forest Degradation at the Core Zone of the Monarch Butterfly Reserve (2024-2025) measures and examines changes in the monarch’s critical forest habitat. It finds that 6.30 acres of forest were degraded between February 2024 to February 2025, a significant decrease when compared to 9.21 acres reported the year before. According to the analysis, 4.58 acres of forest were lost due to illegal logging, 1.3 acres due to forest fires, and.28 acres to drought.

Today’s reports show that, despite challenges, conservation efforts are making a difference. WWF is working with the Mexican government, local communities, and other partners to promote strong forest management and sustainable tourism within Mexico’s Monarch Butterfly Reserve. WWF also supports tree nurseries that help restore the forest in the Reserve and provide economic livelihoods for communities living in the region. In the US, WWF is dedicated to reducing neonicotinoid pesticides, one of the leading drivers of monarch decline and restoring formerly plowed grasslands back to pollinator habitat in the Great Plains.

Every year eastern monarch butterflies travel up to 2,800 miles from Canada and the US to their overwintering sites in the forests of Michoacán and Estado de Mexico, where the Monarch Butterfly Biosphere Reserve (MBBR) is located. Monarchs require a large and healthy forest mass to protect them from winds, rain, and low temperatures that are common at night in these forests.

In addition to providing monarchs the right microclimate conditions for hibernation, the MBBR’s forests are one of the main freshwater contributors to the Cutzamala Hydrological System that provides water to more than 5 million people in Mexico City and its metropolitan area. These forests also boast incredible biodiversity, including 132 species of birds, 56 species of mammals, 432 species of vascular plants, and 211 species of fungi.

WWF-Mexico Director General Maria Jose Villanueva said that these reports indicate conservation measures are going in the right direction. “Despite environmental challenges, today’s announcement shows promising signs of recovery for the migratory eastern monarch butterfly population. We also need to remain vigilant and not forget that this unique migration continues to face many challenges. WWF will continue to work together with local partners, the Mexican government, and especially with the local communities who are most critical to this success.”