# Eastern monarch butterfly population doubles in a year

Migratory insects covered 4.2 acres in Mexican forests this winter but number remains far below long-term average

The population of eastern monarch butterflies – which migrate from Canada and the US to Mexico during the winter – has nearly doubled over the last year, according to a  commissioned in Mexico, generating optimism among nature preservationists.

The modest growth in numbers for the orange-and-black butterflies follows years of ongoing conservation efforts – and perhaps provides a sliver of optimism after otherwise discouraging long-term trends for the species.

Another recent study found that the butterfly population in the US specifically  over the last two decades. And this past December, the US Fish and Wildlife Service  monarch butterflies as threatened under the Endangered Species Act in response to years of advocacy by conservation groups.

A statement from Jorge Rickards, the director general of Mexico’s World  Fund branch, acknowledged the need to convert the short-term gains into long-term ones for monarch butterflies to stop being considered endangered.

“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,” the statement said.

The statement said Rickards’ organization recognized “the key role of local communities, as well as the support of the government of , in … providing this iconic species with the opportunity to thrive”.

The survey, titled Forest Area Occupied by Monarch  Colonies in Mexico During the 2024-2025 Hibernation Season, serves as a crucial indicator of the overall health of the butterfly population. It is part of a series of annual reports by WWF Mexico and Mexico’s National Commission of Protected Natural Areas, in collaboration with local communities.



The report found that monarchs that migrated to central Mexico’s forests occupied 4.42 acres (1.78 hectares), which was up from 2.22 acres during the previous winter.

Nonetheless, though these butterflies occupied nearly twice as much forest habitat compared with previous years, the number of monarchs remains far below the long-term average.

Scientists say that better weather conditions in 2024 – which saw less severe droughts compared with previous years along the butterflies’ migration route – probably contributed to the population growth.

At the end of summer, eastern monarchs fly together from the northern US and southern  to high-elevation fir forests in Mexico. The population size is determined by measuring the area of trees turned a vibrant orange by the clusters of bright butterflies.
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