Butterfly Populations Are Showing Recovery After a Winter in Mexico

Photo: Wikimedia Commons, CC BY-SA 4.0

Monarch butterflies are famous for their striking orange and black wings. These beautiful, elegant insects are also renowned for their impressive migratory regimen. Wintering in Mexico, they travel as far north as Southern Canada in the spring. However, as with many other species, the delicate natural rhythms of their migration are threatened by global warming and habitat loss. Thankfully, during the winter of 2021 to 2022, 35% more butterflies congregated in their winter home than in the past year—suggesting a possible path of resilience for the species.

Each October and November, thousands of monarch butterflies flock to the sheltered, forested mountains west of Mexico City. Typically, they return to northern, cooler climes in March. However, in the 2020 to 2021 season, the butterflies fled in February, suggesting climate change may be altering their pattern due to climate change. Yet in the spring of 2022, the butterflies lingered until April. It is unclear exactly why, but it suggests the species is adapting to a rapidly changing world.

The butterflies rely on trees when in their Mexican home. Logging, fires, drought, and plant disease are exacerbating deforestation. While logging activity rose this past year, other factors caused less damage and resulted in less total loss of flora. Declining milkweed in the United States, which monarch caterpillars eat, has also affected their numbers. Pesticides and clearing wooded areas endanger this vital plant. Activists encourage Americans to plant milkweed to combat habitat loss, but those who live in Mexico should not. The plant might erroneously encourage the insects to linger, interfering with their natural rhythm.

While the butterflies are still at the mercy of climate change, their recently rebounding numbers in Mexico suggest they may be able to adapt their calendar to a changing climate. This past winter, 160,000 tourists flocked to see the magnificent winged creatures gathered in the trees of the butterfly reserves. The butterflies may be adapting—but we humans have to adapt too. Fighting climate change will only make survival easier and surer for this incredible species.

This past winter, more monarch butterflies than the year before flocked to their winter home in Mexico.

Photo: NATICASTILLOG/Depositphotos