These remarkable pollinators are facing a crisis—western populations have plummeted by 96%, while eastern Monarchs experienced a modest rebound in 2025. Conservation efforts are crucial for their survival, as they depend on milkweed to reproduce and play an essential role in ecosystems.

Female Monarch butterfly feeds on purple flowers, showcasing its distinctive orange and black wing pattern, Sebastian County, ArkansasFemale Monarch butterfly feeds on purple flowers, showcasing its distinctive orange and black wing pattern, Sebastian County, Arkansas

The Ups and Downs of Monarch Populations

Monarch butterflies, with their unmistakable orange wings outlined in black and white, have long fascinated people. Their migration is one of nature’s most astonishing spectacles, covering thousands of miles between breeding grounds and overwintering sites.

However, their journey is becoming increasingly precarious, with vastly different trends unfolding on either side of the Rocky Mountains.

Out west, the outlook is bleak. The Xerces Society’s 28th annual Western Monarch Count, released in January 2025, revealed that western Monarchs are in a dire state. Only 9,119 butterflies were recorded during the winter of 2024-2025—a staggering 96% drop from the previous year’s 233,394.

This marks the second-lowest count since monitoring began in 1997, barely surpassing the all-time low of fewer than 2,000 Monarchs in 2020.

To put this into perspective, western Monarch numbers were once in the millions back in the 1980s.

Now, they’re on the brink of disappearing. A stark example? A Nature Conservancy site in Santa Barbara that hosted 33,200 Monarchs last winter recorded just 198 this year.

Meanwhile, eastern Monarchs present a different picture. Overwintering in Mexico’s fir forests, their numbers nearly doubled this winter compared to last year.

According to March 2025 reports from the World Wildlife Fund and Monarch Joint Venture, eastern Monarchs occupied 1.79 hectares (4.42 acres) of forest—up from just 0.9 hectares the year before.

This encouraging increase is likely due to favorable weather in 2024, with fewer droughts along their migration path. Even better, deforestation in the Monarch Butterfly Biosphere Reserve declined by 10%, giving these butterflies a bit more breathing room.

Orange Sulphur butterfly on a Black-eyed Susan, Tishomingo National Wildlife Refuge, OklahomaOrange Sulphur butterfly on a Black-eyed Susan, Tishomingo National Wildlife Refuge, Oklahoma

The Bigger Picture: Butterflies in Trouble

Monarchs aren’t the only butterflies in decline. A large-scale study published in Science in March 2025 found that butterfly populations across the U.S. declined by 22% between 2000 and 2020.

Researchers analyzed data from 12.6 million butterfly observations across nearly 77,000 surveys, revealing that one-third of species are experiencing significant declines.

Shockingly, 107 out of 342 species have lost more than half their population in just two decades, with 22 species plummeting by over 90%. Only 3% of species showed any increase.

Even butterflies once considered common are vanishing. The American lady butterfly population has declined by 58%, while the cabbage white—often regarded as a garden pest—dropped by 50%. The Hermes copper, a rare species from San Diego County, has nearly disappeared, with a staggering 99.9% decline.

What’s Driving the Decline?

Multiple factors are pushing butterflies toward extinction:

  • Climate Change: Rising temperatures are disrupting breeding cycles and migration timing. Monarchs struggle when temperatures exceed 100°F (37.7°C) and perish at 108°F. The record-breaking late summer heat of 2024 likely played a significant role in the western Monarch collapse. Butterflies in northern regions are faring better than their southern counterparts, further highlighting climate change’s impact.
  • Habitat Loss: Expanding agriculture, urbanization, and deforestation have devastated crucial butterfly habitats. Monarchs have been particularly affected by the loss of milkweed—the sole plant their caterpillars rely on. A shrinking number of nectar-rich plants means less food for adult butterflies across many species.
  • Pesticides: Widespread herbicide and insecticide use is killing butterflies directly and contaminating their food sources. A study in California’s Central Valley detected pesticides in every milkweed sample tested, even on properties where no chemicals were applied—demonstrating how pesticide drift is a major concern.

A Glimmer of Hope

Despite the grim outlook, the eastern Monarch rebound proves that butterfly populations can recover under the right conditions. In December 2024, the U.S. Fish and Wildlife Service proposed listing the Monarch butterfly as threatened under the Endangered Species Act. If enacted, this designation could be a game-changer for Monarch conservation.

Individuals can also take action:

  • Plant native milkweed and nectar-rich flowers
  • Reduce or eliminate pesticide use
  • Let sections of yards grow wild with native plants
  • Create habitat spaces, like brush piles, for insects

On a broader scale, stronger pesticide regulations, improved pest management strategies, and climate adaptation measures are critical for butterfly conservation.

The Time to Act Is Now

The contrasting fates of eastern and western Monarchs underscore that their future is still uncertain. With dedicated efforts, we can help butterfly populations rebound—but time is running out.

A 22% decline in just two decades should serve as a wake-up call. Butterflies aren’t merely decorative garden visitors; they are essential pollinators, integral to food webs, and indicators of ecosystem health. If they are in trouble, the environment is, too. When the ecosystem health fails, we humans will also suffer.

The Monarch migration remains one of nature’s most awe-inspiring journeys. Whether future generations get to witness it depends on the actions we take today. The butterflies are signaling distress—it’s up to us to respond.

Life is good, we need to do all we can to keep it that way.

Mia

Click here to see my insect and spider galleries.

Sources

Western Monarch Butterfly Population Decline

Eastern Monarch Butterfly Status

General Butterfly Population Decline