Monarchs face numerous threats, from extreme weather due to climate change to the liberal use of pesticides, like Monsanto’s RoundUp, to habitat loss and fragmentation. And without intervention, they are at risk of going extinct. Monarchs in the West have declined by 99% since the 1980s. Eastern monarchs have declined by over 90% in the same time period.


  • Breeding Habitat Loss: The loss of breeding habitat through much of the United States has strongly influenced the decline in the overwintering monarch population.


  • Overwintering Habitat Loss: Conservation and management actions are needed to ensure the future of overwintering habitats for monarchs in California and Mexico. 


  • Climate Change: Climate change models suggest that changes in the monarch migration and breeding range may force monarchs to change their migratory patterns. 


  • Pesticides: Beneficial insects like monarchs and other pollinators can be negatively affected by the use of pesticides to control unwanted insect and plant species.


  • Natural Enemies: Despite the fact that toxins from milkweed may in some ways protect them, monarchs of all life stages are vulnerable to predation and disease. 


  • Less than 5% of monarch eggs that are laid survive to become adult butterflies.


IUCN Red list

On July 21, 2022 the International Union for Conservation of Nature (IUCN) listed the migratory monarchs as endangered on their Red List of Threatened Species. You might be thinking, “great news, the monarch will finally be protected.” What you might not realize, however, is that while this designation of the monarch as endangered is significant, it doesn’t mean the species will now immediately be legally protected in the U.S.


What’s important to note is that the IUCN has no legal jurisdiction in the U.S. and their listing of the monarch doesn’t have any direct effect on federal protections. For a species to receive those protections here, the U.S. Fish and Wildlife Service (USFWS) must conduct its own Species Status Assessments that inform the decision on whether or not a species requires protection under the federal Endangered Species Act (ESA). USFWS has a different meaning for the terms “endangered” and “threatened” than the IUCN does and it has NOT listed the monarch as an endangered species—yet.


That said, USFWS hasn’t ignored the situation. Back in 2020, USFWS completed a Species Status Assessment of the monarch species, including the North American migratory monarch and all the non-migratory monarch populations located in the US and other countries. They determined that protections for the species are “warranted” but are precluded by higher priority listing actions. This means that a final decision on the monarch is delayed while the agency prepares regulations for other species that are in a more critical state. We hope to hear the final USFWS decision on monarchs by 2024. Until then, the monarch remains a “candidate species” for listing—and protection—under the ESA.

On September 27, 2023, the IUCN revised the listing of monarch butterflies from “endangered” to “vulnerable.” The change came from a petition that was submitted by Dr. Andy Davis, an independent scientist, who point out methodological errors with the initial assessment. The IUCN re-examined the data being used to assess the population and agreed that the population is not endangered, but does qualify (for now) as “Vulnerable.”