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For Immediate Release, February 7, 2024


Media contacts:

Scott Hoffman Black, Director, Xerces Society for Invertebrate Conservation, 503-449-3792, [email protected]

Emma Pelton, Western Monarch Lead, Xerces Society for Invertebrate Conservation, 503-212-0706, [email protected]

MEXICO CITY, February 7, 2024 – The annual census of monarch numbers at the overwintering sites in central Mexico was released today by World Wildlife Fund-Mexico and partners. It revealed that in just one year, the presence of monarch butterflies in their Mexico wintering grounds dropped by more than half, from 2.2 hectares to 0.9 hectares.


This makes 2023-24 the second worst year ever recorded. The lowest year was in 2013-14 when only 0.67 hectares were occupied. The annual survey, led by WWF-Mexico, measures the area of forest in which monarch butterflies hibernate each winter, providing a reliable indicator of the migratory eastern monarch’s overwintering population status. 


"Fewer monarchs hibernating in their traditional forest habitat in Mexico greatly concerns all of us. It's critical that all communities, governments, non-governmental organizations, scientists, and others continue to strengthen our conservation and protection efforts to support the monarch's unique migration," said Jorge Rickards, general director of WWF Mexico.


“I am very concerned with the monarch numbers out of Mexico this year,” said Scott Black, the executive director of the Xerces Society for Invertebrate Conservation, which manages the Western Monarch Count. “We need to move forward on listing monarchs under the Endangered Species Act in the U.S., to maximize protection and restoration of habitat across the monarch’s range and take action to protect these animals from toxic pesticides." 


The news follows the recent Western Monarch Count announcement, which found western monarch overwintering numbers were down in coastal California, as well.

“The eastern monarch overwintering population has historically been much larger, estimated at millions individuals compared to 233,394 butterflies in the Western Monarch Count this year,” said Emma Pelton, the western monarch lead for the Xerces Society. “But both of these populations need their overwintering habitat protected and to have those protections actually enforced if we want them to survive.”

Despite ongoing efforts to preserve their migration, monarchs across North America face significant challenges, including habitat destruction, pesticide exposure, and extreme weather exacerbated by climate change. Some population fluctuation is normal, but the overall trend continues to be below historic norms in both the eastern and western migratory populations.


The Xerces Society is part of a tri-national delegation working on a plan to protect monarch butterflies throughout their migratory range through Mexico, the United States, and Canada. There are many issues that need to be addressed to ensure survival. One priority concern is ensuring that the first generation of monarchs in the multi-generation migration is as large as possible, setting up the population for successful growth. This means protecting and restoring climate-resilient habitat in Texas and California, where the first generation emerges for the eastern and western populations, respectively, as well throughout the range. The butterflies are also in need of improved protection from pesticides, which are used widely in retail, home and agricultural landscapes.

What you can do:


View the complete reports from World Wildlife Fund-Mexico, available in Spanish only.

For more information regarding the reports, contact: Eduardo Rendón-Salinas, Director del Programa Ecosistemas Terrestres, WWF México, [email protected], +52 (715) 1535055 y 1535466