Monarch Butterflies in Mexico Surge 64% in Winter 2025-26

Mexico City: The monarch butterfly population at their hibernation sites in the oyamel forests of Michoacán and the State of Mexico recorded a 64% increase in the 2025-2026 winter compared to the previous cycle, according to data released by Al Jazeera in March 2026. The news represents a breath of fresh air for conservationists who have been monitoring the dramatic decline of this species, classified as endangered.

Monarch butterflies (Danaus plexippus) complete each year one of the most spectacular migrations in the animal kingdom, covering thousands of kilometers from southern Canada and northern United States to the temperate forests of west-central Mexico, where they spend the winter congregated in numbers that can darken the sky. The species was included in the Red List of the International Union for Conservation of Nature (IUCN) as endangered in 2022.

Factors Explaining the Recovery

Researchers attribute the rebound to a combination of favorable factors: more benign climatic conditions during the fall migration, greater availability of milkweed plants (Asclepias), the monarch's exclusive host plant, in the north-central states of the US and Canada, and reduced use of herbicides in agricultural areas adjacent to migration routes. Reforestation programs in Mexican sanctuaries have also contributed to improving the quality of the hibernation habitat.

Tourism and Conservation in Michoacán

The monarch butterfly sanctuaries in Michoacán, a UNESCO World Heritage Site, receive hundreds of thousands of visitors each winter season, generating significant income for local communities. The forest ejidos of El Rosario and Sierra Chincua are the main destinations to observe the phenomenon. Mexican environmental authorities call for maintaining protective measures throughout the year to consolidate the observed recovery.