Monarch Butterflies Now Considered Endangered

Migratory monarch butterflies — the much-loved orange-and-black insects known for their impressive annual journey that takes them thousands of miles across North America — are now considered endangered.

The International Union for the Conservation of Nature (IUCN), a group headquartered in Switzerland that tracks species and extinctions, added the migratory monarch butterfly (Danaus plexippus plexippus) to its Red List of Threatened Species.

The migratory monarch butterfly is a subspecies that breeds over the summer throughout Canada and the United States before traveling south to California and Mexico for the winter.

IUCN scientists estimate that populations of the insects have shrunk 22 percent to 72 percent over the past decade.

Warmer temperatures, years of intense drought and severe wildfires — all elements that are exacerbated by climate change — are transforming the land and reducing the availability of plants that these monarchs need to breed and fuel their long migratory journeys.

The insects are also affected by the overuse of pesticides and habitat loss from agriculture and urban development.