Monarch butterflies overwintering in Mexican forest preserves and California groves face welfare challenges from temperature extremes, habitat degradation, and illegal logging.
Monarchs caught in winter storms or extreme cold while clustered experience death from hypothermia. Deforestation reduces the thermal buffering provided by dense forest canopy, exposing butterflies to lethal temperature swings. The fragmentation of overwintering habitat means some butterflies cannot find suitable sites and die from exposure. While insect sentience remains uncertain, the precautionary principle supports concern for welfare given the scale of mortality during winter events and habitat loss.