For years the story of the monarch butterfly was a countdown. The insect that streams south by the hundreds of millions each autumn, from Canada and the United States to a few mountain forests in central Mexico, had been declining so steadily that people started writing about the migration in the past tense - one of those wonders our children might only see in footage. The latest count is a reason to put the eulogy away.
The annual overwintering census, produced by WWF-Mexico and Mexico's protected-areas commission, CONANP, found monarchs occupying 2.93 hectares of forest this past winter, measured across the December 2025 colonies [1]. The winter before, the figure was 1.79 hectares [1]. That is a 64 percent increase in a single year. In the units more familiar to US readers, the butterflies blanketed 7.24 acres, up from 4.42 [2].
Data
| Winter 2024-25 | 1.79 hectares |
|---|---|
| Winter 2025-26 | 2.93 hectares |
The method is worth a sentence, because it explains why the number is trustworthy. Nobody counts monarchs individually - there are far too many. Instead, because the butterflies cluster so densely on the oyamel fir trees that they bend the branches, scientists measure the area of forest the colonies cover. More area means more monarchs, and this year the area grew by nearly two-thirds. This season's 2.93 hectares even edges slightly above the average of the past decade, 2.81 [1].
The most important thing to say about this is also the most hopeful way to say it honestly: it is a comeback, not a rescue. The population is still below its historic levels, and still under the roughly six hectares that researchers associate with a stable, resilient migration [2]. A single good winter does not undo decades of loss of the milkweed the caterpillars need or the pressures of a changing climate. What it does is change the direction of the line - and it has now changed it two years running, the first back-to-back increases in a long time.
There is something bracing about a species people had mostly given up on posting its best number in years. The monarchs did not read the obituaries. Somewhere over Texas this spring, the great-grandchildren of the butterflies that filled those 2.93 hectares were already heading north, and next winter's census will measure whether the line keeps bending their way. For now, the count is up 64 percent, twice in a row, and that is simply good news.
