Monarch Butterfly Welfare and Conservation

Monarch butterflies undertake one of the world's great migrations, but populations have collapsed by 80-90% due to milkweed loss, pesticides and climate change.

Key Facts

Western monarch populations collapsed from 1.2 million in the 1980s to under 2,000 in 2020 before partial recovery
Monarchs require milkweed as the sole larval food plant — its agricultural elimination is the primary cause of decline
Climate change is disrupting migration timing and overwintering site quality
Neonicotinoid pesticide residues in milkweed plants poison monarch caterpillars
The Mexico overwintering sites are threatened by illegal logging and climate-driven temperature change

Welfare Considerations

Individual monarchs navigating a 4,000 km migration over multiple generations face pesticide exposure, predation and habitat loss throughout their journey. Caterpillars feeding on pesticide-contaminated milkweed develop abnormalities and die before pupation. The collapse of overwintering aggregations — once numbering hundreds of millions of individuals — represents an enormous reduction in total butterfly welfare across the population. Milkweed restoration is the single most impactful individual welfare intervention available.

What You Can Do

Plant native milkweed species in your garden — this is the most direct action for monarch welfare
Avoid pesticide use on milkweed and adjacent flowering plants
Support the Monarch Joint Venture milkweed restoration programmes
Advocate for milkweed preservation in agricultural margins and roadsides