The number of monarch butterflies overwintering this year in Mexico has nearly doubled, according to the annual census released last week by the World Wildlife Fund in Mexico and their partners.
During the last few months in 2025, the population of eastern monarchs occupied 4.42 acres of central Mexico’s forests—up from 2.22 acres during the previous winter.
The encouraging survey was conducted with help from Mexico’s National Commission of Protected Natural Areas and local communities, and it serves as an important indicator of the health of a monarch population that has been clawing its way back from dangerously low levels this century.
“It’s now time to turn this year’s increase into a lasting trend with an all-hands approach where governments, landowners, conservationists, and citizens continue to safeguard critical habitats along the monarch’s North American migratory route,” said Jorge Rickards, director general of WWF Mexico, who recognized the key role of local communities and the government of Mexico in conserving the forest that provides an annual respite to this iconic species.
Scientists attribute much of this year’s population growth to better weather conditions in 2024—with less severe drought than in previous years along their migration route from the U.S. and Canada to Mexico.
Forest protections are also improving
A second report shows that forest degradation in the Monarch Butterfly Biosphere Reserve where they overwinter has improved by 10%. Between April 2023 and February 2024, nine acres of forest were damaged, down from 10 acres reported the previous year. The causes of habitat degradation were either illegal logging (6 acres); natural causes or drought (2.5 acres); or the removal of trees to prevent disease spread (.5 acre).
“If we want these butterflies to recover, they need more habitat restoration and better protection from pesticides,” said Emma Pelton, the western monarch lead for the Xerces Society. “They were proposed to be listed as threatened under the Endangered Species Act last December, and this listing urgently needs to be finalized.”
The numbers of these hardy yet delicate flyers have jumped and dipped—both up and down—in the last three decades. For instance, the Western migration of monarchs in California bounced back in a big way in 2021, 2022 and 2023, but are dipping again this year.
Come to the rescue: plant the only food monarch babies eat
There are many ways you can help this species thrive in North America, but one of the best is to plant milkweed. The milkweed plant is essential to the monarch: It is the only plant on which they lay their eggs and the only source of food for baby monarch caterpillars. As spring arrives, the butterflies start their migration back north, seeking out milkweed to lay their eggs. They also need nectar plants to eat themselves.
Your small action can make a big difference, but different species of milkweed grow better in different parts of the country. Use this milkweed map to find the one that thrives in your region of the United States.
GET INVOLVED: Help the Monarch Population by Raising Them Yourself
Every year, monarch butterflies make an extraordinary journey: at summer’s end, they migrate from southern Canada and the northern United States to mountain forests in Mexico, with some traveling nearly 3,000 miles. After winter, these same butterflies fly an additional 600 miles north to the United States. There they lay eggs on milkweed plants, completing their unique eight-month life cycle.
The next three to five generations, each living only three to five weeks, continue the migration northward. Eventually, they reach breeding sites in the northern United States and southern Canada, completing the annual migration cycle.
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