Monarch butterflies undertake one of the most remarkable migrations in the animal kingdom, and understanding their welfare through habitat loss and climate change informs the conservation action needed to protect their journey.
Applying a welfare lens to monarch butterfly conservation requires engaging with the debate about invertebrate sentience, as the capacity of insects to experience suffering is uncertain. What is clearer is that the population collapse of monarchs represents a loss of one of the natural world's most extraordinary phenomena, and the individual mortality of millions of butterflies from habitat loss, pesticides, and climate-induced starvation has welfare implications under the precautionary principle. The migration journey itself, timed to access nectar resources and avoid weather extremes, becomes more stressful as climate change disrupts the timing and availability of those resources. Conservation action that restores milkweed and native nectar plant corridors along migration routes directly improves the conditions for monarch survival.