Celebrating 50 Years of Monarch Butterfly Migration to Mexico

Each autumn, millions of monarch butterflies make a remarkable journey from the northeastern United States and southeastern Canada to the mountainous regions of Michoacán, Mexico, where they hibernate for the winter. This year marks the 50th anniversary of the discovery of their hibernation sites by naturalists Catalina Aguado and Kenneth Brugger, who identified these locations in 1975 after a two-year search. The Monarch Butterfly Biosphere Reserve, a UNESCO World Heritage site, spans over 56,000 hectares and hosts an estimated 37.5 million butterflies per hectare during their stay. This migration is not only ecologically significant but also culturally meaningful, coinciding with the Day of the Dead celebrations, as the Purépecha people historically viewed the butterflies as the souls of the deceased returning to visit their families.

Key Details: • The migration occurs from November to March, with butterflies needing 16°C to fly. • The Monarch Butterfly Biosphere Reserve is located in Michoacán, Mexico, covering 56,259 hectares. • The butterflies travel between 1,900 and 4,500 kilometers during their migration. • The migration coincides with the Day of the Dead, a culturally significant time in Mexico.