Monarch butterfly population decline from milkweed loss and climate change represents a welfare concern alongside the conservation emergency of this iconic migrant.
Monarch butterfly welfare encompasses both the individual experience of migrating butterflies — a physiologically demanding journey of thousands of miles — and the population-level welfare of larvae that cannot develop without milkweed. Whether individual monarchs have experiences that matter morally is uncertain, but the ecological welfare implications of their decline are clear: monarchs are indicator species whose decline signals broader pollinator community collapse. Milkweed planting at scale along migration routes directly addresses a key limiting factor in monarch population recovery.