Butterflies sit on a pine tree at Monarch Grove Sanctuary in Pacific Grove, Calif. Researchers say that the population of western monarch butterflies is well below what it used to be.
Nic Coury / AP
One of the most recognizable and widely dispersed insects in North America may soon be headed for protections under the Endangered Species Act.
In early December, federal wildlife officials will decide whether the monarch butterfly, which pollinates plants and flutters through backyards in nearly every U.S. state, is deserving of federal protections.
The decision comes after a decade of efforts by wildlife groups, ecologists as well as non-scientists, who have documented declining monarch populations. And a diverse network of monarch enthusiasts, conservation efforts and landowners are anxious to see whether or how the federal government plans to protect the widespread monarch.
“I think for the general public and for a lot of scientists, it [might] feel kind of strange to have formal protections for something that spans the continent and reaches very high numbers in the summer,” said Matt Forister, a plant and insect ecologist at the University of Nevada, Reno. “But I think that’s a sign that the world is in that state, like the threats are that severe."
“It’s a new frontier,” he said.
The U.S. Fish and Wildlife Service (FWS) said if protections are still deemed necessary (in 2020 the agency said they were warranted but precluded by higher priorities), it plans to submit a proposed rule to the Federal Register by Dec. 4, 2024. That rule would still be subject to public comment and possible revisions before taking effect.
The expectation from many monarch experts is that FWS will propose to list the monarch butterfly under the Endangered Species Act as threatened – not endangered – with accommodations for some of the people and industries that interact with the migrating species day-to-day.
During their migration, monarchs depend on flowering plants and milkweed, often found on private land. State, local and private efforts are underway to plant and protect milkweed. Monarch advocates hope a listing would better coordinate those efforts and give them a sizable boost, but there are concerns it could also spoil goodwill.
“I think there’s a big concern amongst farmers in particular,” said Brigit Rollins, a staff attorney at the National Agricultural Law Center. “We’ve done all this work we’ve been trying to do right by [monarchs], but maybe now we’re going to be in a position where our good work makes it actually harder for us once the species is listed.”
An incoming Trump administration also muddies the water. The previous Trump administration postponed the decision to list the monarch and rolled back some endangered species protections.
Monarch populations have been declining for decades
Alarm bells have been going off for those following monarch populations for years.
Monarch butterflies migrate over generations – their offspring, or great-great-great offspring completing the journey – so their populations can fluctuate greatly.
“There’s a lot of noise in the data,” said Cat Darst, a wildlife biologist and assistant field supervisor with FWS, who’s helping with the agency’s species status assessment for the monarch. “You can’t just look at one good year or one bad year. You have to look at data over time.”
The overall trend has been pretty clear, she said. “And that is down.”
Eastern monarch populations, which migrate between Canada and overwintering sites in Mexico, are estimated to have declined by more than 80 percent since the 1990s. Counts at overwintering sites on the California coast estimate that Western monarch numbers have plunged by more than 95 percent since the 1980s.
“We are seeing staggering declines,” said Cheryl Schultz, a butterfly ecologist at Washington State University.
There are three prominent drivers of the declines: habitat loss, pesticides and climate change. Overwintering grounds on the California coast and Mexico have been destroyed. Milkweed plants, which monarch larvae and caterpillars feed on, have been torn out for sidewalks, tennis courts and crops. Some of the flowering plants that remain are covered in harmful pesticides. Worsening wildfires, droughts and heatwaves are putting even more habitat at risk.
“You want to have an overall landscape that supports your butterflies so [their populations] can be bouncing way up high and not bouncing so low that when they crash, they’re not able to come back up,” Schultz said.
In 2014, wildlife groups petitioned FWS to protect the monarch butterfly under the Endangered Species Act. In 2020, after years of litigation from the Center for Biological Diversity, the agency declared that the species was deserving of federal protections, but those protections wouldn’t be given because of higher priorities. After more litigation, FWS was mandated by a court to make a new determination by early December 2024.
Darst said the agency intends to meet that deadline and make a new determination but could not speculate as to what it will decide.
“One of the coolest things about the fact that monarchs are kind of everywhere is that everyone can get involved with conservation. And there’s not a species where everyone can get involved,” she said. “One of our goals at the U.S. Fish and Wildlife Service is to maintain that magic for the public.”
The difference between threatened and endangered
The expectation from many following the process is that FWS will propose to list the monarch butterfly as threatened – not endangered.
A species listed as endangered gets the full suite of federal protections. It’s illegal to kill, capture, harass or harm one. A threatened species doesn’t automatically get the same protections. Federal wildlife managers can tailor protections to allow some activities that might harm, harass or kill a threatened species to continue.
“We really want to see some common sense middle ground about exempting activities that are beneficial,” said Emma Pelton, senior endangered species biologist at the Xerces Society for Invertebrate Conservation, one of the groups that’s been pushing for federal protection. “This is a unique animal. It’s in classrooms, it’s in homes, it’s in gardens, it’s used in educational outreach. So we don’t want to see that taken off the plate.”
But it’s also important, she said, that a ruling doesn’t exempt so many activities that it makes the protections ineffective at stopping monarch declines.
“I’m really interested in how the service strikes that balance,” Pelton said. “And I think this is where it will be a little bit groundbreaking – and hopefully in a really good way. How do we get large-scale landscape conservation moving without creating a lot of regulatory fear?”
The biggest fears may come from the agricultural community, which has a lot at stake.
Rollins, who talks to farmers in the heartland of the U.S., said if FWS designates wide areas as critical habitat for monarch butterflies it would impact where farmers plow and plant. A listing could also possibly limit their use of insecticides and herbicides.
“There’s a lot of concern about how listing the monarch butterfly could impact use of pesticides,” she said.
Interest groups on every side of the issue are planning to closely read the proposed rule and flag concerns during the 60-90-day public comment period that follows. A final rule likely would be published later in 2025.
Forister said it may be easy for people to look at the plight of the monarch butterfly and think the federal government should be focused on species with smaller ranges.
“That’s not the future,” he said. “The threats are so widespread now that it’s even affecting widespread species so we got to take this on. Conservation on a large-scale, that’s what we got to figure out how to do as a society.”