Monarch butterfly populations have declined by over 80% in recent decades due to habitat loss, pesticide use, and climate change. Protecting their habitat supports the welfare of billions of individual insects.
Insect welfare is an emerging and contested area of animal ethics, but the scale of monarch decline — billions of individuals lost across decades — warrants serious consideration regardless of where one draws the line on insect sentience. The welfare implications of habitat loss for monarchs include starvation of caterpillars when milkweed is absent, failed migrations when nectar sources are depleted, and mass mortality at overwintering sites affected by logging or weather extremes. Supporting monarch habitat restoration is simultaneously a conservation and a potential welfare action at enormous scale. The accessibility of individual action — planting milkweed — makes this one of the most democratic wildlife welfare opportunities available to ordinary people.