Wild Monarch Butterfly: Population Collapse and Welfare of Pollinators

While butterfly sentience remains uncertain, the collapse of monarch populations represents a welfare and biodiversity crisis that demands attention.

Key Facts

Eastern monarch butterfly populations have declined by approximately 80% since the 1980s
Western monarchs nearly went extinct in 2020-2021, with populations recovering slightly but remaining critically low
Habitat loss (milkweed removal from agricultural landscapes), climate change, and pesticides drive the decline
Monarchs migrate up to 4,500 km from breeding grounds to Mexican overwintering sites — one of nature's most remarkable journeys
Whether butterflies experience pain or suffering is genuinely uncertain given their simple nervous systems
Mass die-offs from pesticide application and climate events kill millions of monarchs annually

Welfare Considerations

Monarch welfare sits at the edge of our current understanding of invertebrate sentience. With simple nervous systems, they are unlikely to have rich subjective experience, but even minimal welfare consideration is warranted given the precautionary principle and the scale of human-caused mortality. More clearly, the collapse of monarch populations represents the loss of a natural wonder with profound implications for ecosystem function and human wellbeing — including the wellbeing of the many people who find meaning and joy in monarch migrations. Habitat restoration, pesticide reduction, and climate action simultaneously address monarch welfare (to whatever extent it exists) and the broader ecological and cultural dimensions of their decline.

What You Can Do

Plant native milkweed in your garden — it is the only plant monarch caterpillars can eat
Reduce or eliminate pesticide use in your garden, particularly systemic insecticides
Join monarch monitoring programs like the Western Monarch Thanksgiving Count
Support Xerces Society campaigns on pollinator habitat restoration
Advocate for milkweed restoration on roadsides and agricultural land through state programs
Donate to monarch overwintering habitat protection programs in Mexico and California