Monarch butterflies are now a candidate for listing under the Endangered Species Act. The butterflies qualified to be added to the list of threatened and endangered species, but the U.S. Fish and Wildlife Service’s work on higher-priority listing actions prevented the species from the list.
“We conducted an intensive, thorough review using a rigorous, transparent science-based process and found that the monarch meets listing criteria under the Endangered Species Act. However, before we can propose listing, we must focus resources on our higher-priority listing actions,” said U.S. Fish and Wildlife Service Director Aurelia Skipwith.
Over the past two decades, scientists have noted declines in North American monarchs overwintering in Mexico and California, where these butterflies cluster. At a density of roughly 8.5 million monarchs per acre, it is estimated that the eastern population fell from about 384 million in 1996 to a low of 14 million in 2013. The population in 2019 was about 60 million.
The western population, located in California, saw a more precipitous decline, from about 1.2 million in 1997 to fewer than 30,000 in 2019.
The butterflies will be reviewed again each year until they are no longer a candidate for the list. For more information on how to save the monarch, click here.