PORTLAND, Ore.; December 10, 2024—The U.S. Fish and Wildlife Service has proposed to list the monarch butterfly as a threatened species under the U.S. Endangered Species Act, as announced today. The butterfly is widely known for its continent-spanning migration and occurs in every U.S. state except Alaska.
This announcement came as the result of a listing petition submitted in 2014 by the Xerces Society for Invertebrate Conservation, the Center for Biological Diversity, the Center for Food Safety, and the late monarch scientist Lincoln Brower.
“We welcome this decision to protect monarchs as threatened under the Endangered Species Act,” said Sarina Jepsen, endangered species program director of the Xerces Society. “The recent counts from monarch overwintering sites in both Mexico and California have been extremely low, which underscores that monarchs need protection immediately. Sites that used to host tens of thousands of monarchs now have just a few butterflies.”
Scientists estimate that since monitoring began in the 1980s and 1990s, monarch butterflies have declined by approximately 80% in their eastern population and more than 95% in their western population. The overwintering area occupied by eastern monarchs in Mexico’s oyamel forests dropped to just 2.2 acres last winter, down from 5.4 acres the year prior and as much as 44.9 acres in the late 1990s. Early monitoring this fall by the Xerces Society at western monarchs overwintering groves in California suggests it will be the second lowest population year since the late 1990s.
“It may seem surprising that a species that many of us are used to seeing in our parks and gardens is in trouble, but the long-term data has shown that monarchs are in serious decline. We want to reverse that before it’s too late,” said Emma Pelton, a monarch conservation biologist with the Xerces Society. “The fact that monarchs spend their winters closely packed into small areas of forest in coastal California and central Mexico makes them especially vulnerable.”
The monarch faces many threats, including the loss of milkweed—the preferred plant its caterpillars eat—and other flowering plants across its range. Monarchs have also declined due to the degradation and loss of forests they rely on for winter shelter in both coastal California and Mexico, and the widespread use of pesticides in the environment. Many of these stressors are worsened by the effects of climate change.
Monarchs fly up to 3,000 miles to complete their migration. They don’t quit, and neither will we until they are recovered,” said Scott Black, director of the Xerces Society. “This is an ‘all hands on deck’ conservation issue. The Xerces Society will continue working with everyone from farmers and ranchers, to managers of roadsides and energy infrastructure, to individual enthusiasts to restore monarch habitat and help these inspiring animals.”
Everyone can be a part of the solution to recover monarch butterflies. Visit xerces.org/monarchs to learn more about how to help.
The Fish and Wildlife Service will be hosting a virtual presentation for stakeholders to go over the proposal and take questions on Friday, December 13, at 3:00pm EST/12:00pm PT.
