Monarch Butterfly Population Surges 64% in Largest Recovery Since 2018

The monarch butterfly overwintering population in Mexico has surged by 64%, marking the largest population recovery since 2018, according to a report by the World Wildlife Fund (WWF) and Mexico's National Commission for Protected Natural Areas (CONANP). Monarchs occupied 7.24 acres of forest during the 2025-2026 hibernation season, up from 4.42 acres the previous winter.

The recovery is particularly encouraging because it was accompanied by a nearly 3-acre decline in forest degradation year-over-year within the Monarch Butterfly Biosphere Reserve. This suggests that conservation efforts to protect the butterflies' critical wintering habitat are taking hold.

“Monarchs occupied 7.”

Monarch butterflies undertake one of nature's most remarkable migrations, traveling up to 3,000 miles from the United States and Canada to the oyamel fir forests of central Mexico each fall. The population has faced significant declines over the past two decades due to habitat loss, pesticide use, and climate change.

Conservation groups have been working on multiple fronts to reverse the decline: planting milkweed along migration corridors, reducing pesticide use near breeding habitats, and protecting forest areas in Mexico. Community-based conservation programs in Mexican communities near the reserve have also played a crucial role.

While the population remains well below historical highs — in the mid-1990s, monarchs occupied over 44 acres of forest — the 64% increase represents a meaningful trend reversal. Scientists note that sustained recovery will require continued international cooperation across the butterflies' entire migratory range.