Conservation efforts target monarchs as ESA decision looms

By Michael Doyle | 05/20/2024 01:17 PM EDT

The Fish and Wildlife Service has committed to making its call on protections for the butterfly by December.

A kaleidoscope of Monarch butterflies hang from a tree branch.

Monarch butterflies are shown in January 2015 hanging from a tree branch in the Piedra Herrada sanctuary near Valle de Bravo, Mexico. Rebecca Blackwell/AP

Judgment day approaches for the monarch butterfly.

Bound by a court settlement, the Fish and Wildlife Service is supposed to decide by early December whether the monarch warrants listing as threatened or endangered. Although the agency misses many Endangered Species Act deadlines, it appears determined to meet this one after several years of study.

“We wanted to make sure that we have all the best science available … and we wanted to make sure that we were able to gather all that information and make a quality decision,” said Nicole Alt, director of FWS’ Center for Pollinator Conservation.


With the migratory butterfly passing through dozens of states, a decision to list the species could be accompanied by the designation of an expansive critical habitat. Combined with other regulatory implications, this could make the long-delayed monarch listing call one of the most consequential actions in the history of the ESA. It also appears likely, some monarch experts say, given the bleak population trends that led FWS to conclude in 2020 that “monarch viability is declining and is projected to continue declining over the next 60 years.”

Despite the dire circumstances, a campaign to help the monarch butterfly has been advancing on multiple fronts but without a unified commander in chief. Rather, the monarch’s allies march under different flags that reflect a dispersed approach toward species conservation. Some study the insect, some set aside habitat and some tinker with new tools, all without reference to a species recovery plan that an ESA listing would mandate.


  • From an urban office building, a program administered by the University of Illinois, Chicago’s Energy Resources Center has recruited energy companies, state departments of transportation and counties into conserving hundreds of thousands of acres as butterfly habitat on rights of way, such as the medians between roads.
  • On sprawling Fort Cavazos — formerly Fort Hood — in Texas, biologists prowl the grounds in search of adult monarchs as well as eggs and larva. Since 2017, they estimate they have collected information from more than 10,000 tagged adult monarchs and forwarded this data to another team of collaborators with the Monarch Watch program based at the University of Kansas.
  • From her Denver office, Alt oversees four geographically scattered FWS staffers and collaborates with others in and out of government. With yet another allied group called Monarch Joint Venture, for instance, the Center for Pollinator Conservation is supporting studies of drones and artificial intelligence in measuring milkweed distribution on wildlife refuges.

And, scattered as they are, the various monarch teams, researchers and advocates periodically gather for a meeting of the minds, as they did in the summer of 2022 for a first-of-its-kind Capitol Hill butterfly summit where Interior Secretary Deb Haaland announced establishment of Alt’s pollinator center.

“It’s really been exciting to see the level of interest from lots of different sectors,” Alt said, adding that “different people want to work in different ways and in different spaces … and in the vast majority of situations they are all advocating for the same thing.”

Some conservation groups, however, want to see a more urgent focus on the problem, saying Congress needs to dramatically increase funding to help the monarchs truly recover. In letters sent last week to House and Senate appropriators, the Center for Biological Diversity and other environmental groups called on lawmakers to provide $100 million annually to restore 1 million acres of pollinator habitat in this country each year and another $30 million to preserve forests in Mexico where some of the butterflies spend their winters.

The groups noted how people over generations have heralded the black-and-orange butterfly’s “spectacular beauty and epic, life-affirming migrations.”

“Dedicating $100 million a year to monarch conservation gives these beloved butterflies a fighting chance at survival,” one letter said.

Long journey

An adult monarch typically weighs about one-half of a gram but is an endurance athlete that can flap its wings and ride air currents for upward of 30 miles a day.

The population east of the Continental Divide migrates thousands of miles to winter habitats in Mexico. In the spring, monarchs travel north to Canada over two to three successive generations, breeding along the way.

Western monarchs overwinter primarily along California’s coast and in Baja California.

Both populations rely on milkweed, which caterpillars eat and butterflies lay their eggs on. As milkweed habitat shrunk, done in by herbicide spraying, indiscriminate mowing and other practices, the monarchs began to decline.

In 2014, the Center for Biological Diversity and several other environmental groups petitioned FWS to list the monarch under the ESA. Litigation ensued, until in December 2020 when FWS declared that listing the monarch under the ESA was warranted but precluded by work on higher-priority listing actions.

At the time, the monarch’s eastern population was estimated to have fallen from about 384 million in 1996 to about 60 million in 2019.

In 1997, when the Xerces Society began its western monarch counting project around Thanksgiving, volunteers tallied over 1.2 million overwintering monarchs, which then dropped to fewer than 30,000 in 2019. The 2023-2024 census showed a rebound from that point, with around 233,000 butterflies counted in the overwintering sites.

If FWS does decide to list the monarch, it will be across the country. Wendy Caldwell, executive director of the St. Paul, Minnesota-based nonprofit Monarch Joint Venture, said that while subspecies or population segments of vertebrates can be given protections under the ESA, for invertebrates they cannot be broken up for listing purposes.

“So in the case of monarchs, the listing decision will be based on the species as a whole, not distinct population units,” Caldwell said.

After more litigation from environmental groups, FWS in May 2022 agreed to a settlement, saying it would complete another ESA determination for the monarch by Sept. 30 of this year. Last March, the agency secured an extension of the deadline until Dec. 4. in order to have “sufficient time to consider the best available scientific and commercial data” in its final review.

Caldwell, whose group collaborates with state and federal agencies, universities, farm groups, and others on assorted butterfly and habitat conservation efforts, noted that efforts so far to boost the monarch have been decentralized.

“Up until [now] monarch conservation has been voluntary in nature,” said Caldwell. “So I think that’s where you see a little bit of the decentralized nature of conservation efforts because it’s a known issue and challenge but it doesn’t come with any sort of congressional mandate or protections of Endangered Species Act or anything like that.”

Milkweed matters

Milkweed in a field at the Patuxent Wildlife Research Center in Laurel, Maryland, Friday, May 31, 2019. Farming and other human development have eradicated state-size swaths of its native milkweed habitat, cutting the monarch butterfly's numbers by 90% over the last two decades. It is now under considered for listing under the Endangered Species Act. (AP Photo/Carolyn Kaster)
Milkweed in a field at the Patuxent Wildlife Research Center in Laurel, Maryland. | Carolyn Kaster/AP

Last October, the board of commissioners for Minnesota’s St. Louis County did some cost-benefit calculating and cut a butterfly deal.

The rural county officials agreed to conserve monarch butterfly habitat through practices such as planting milkweed, mowing less or reducing pesticide use on the grass and plants along at least some of the county’s roughly 3,000 miles of roads. In return, the county received assurances that it will not be required to implement additional conservation measures on the covered road areas, even if the species is eventually listed as endangered.

The deal was the latest in what is awkwardly called a “candidate conservation agreement with assurances,” or a CCAA. These agreements, which are authorized by FWS, aren’t limited to monarch butterflies. Oil and gas industry interests, for instance, joined in a 2014 agreement covering lesser prairie chicken habitat in Kansas and four other states.

The monarch CCAA, though, is the only agreement of its kind that has the potential to cover all lower 48 states. It is administered by the University of Illinois, Chicago’s Energy Resources Center and was launched in 2020 by the Rights-of-Way as Habitat Working Group, which encourages creating monarch habitat in places like medians and transmission line routes.

The working group was formed in 2015 and consists of several hundred representatives from industry, government agencies, nonprofits and academia.

So far, about 930,000 acres in 42 states have been enrolled or are in the application process.

Kandiyohi County, west of Minneapolis, became the nation’s first county to enroll its roads in the program in March 2020.

“With the monarch butterfly potentially being listed as endangered, it is likely a matter of time before mitigation will be mandated,” Roger Imdieke, chair of the Kandiyohi County Board of Commissioners, told E&E News. “By volunteering our road right of ways as a refuge, we felt like we could preemptively meet and exceed mitigation.”

Imdieke added that “the challenges were very minimal” and he predicted that the county’s initial cost of around $6,000 and ongoing annual administrative cost of about half that amount “will be less than had we not enrolled, and the monarch becomes listed as an endangered species.”

The program’s goal is to enroll 2.3 million acres by December 2025. If FWS proposes listing the species this December, that’s when the listing would likely become final and ESA protections kick in.

“We’ll never know until it officially comes out,” noted Megan Petraitis, a senior program manager with the Energy Resources Center. “But given the recent monarch overwintering numbers that are still well below recorded numbers in the ’90s and given that we’re not seeing a huge resurgence in their numbers, we do anticipate a listing of the monarch.”

Drones and AI

A Monarch butterfly is pictured.
The Fish and Wildlife Service has until Dec. 4 to decide whether the monarch butterfly should be listed under the Endangered Species Act. | Pedro Pardo/AFP via Getty Images

Some monarch conservation tactics are time-tested, like grants to protect habitat.

The National Fish and Wildlife Foundation runs a Monarch Butterfly and Pollinators Conservation Fund that in 2023 provided $4.1 million for 18 projects. One typical grant, for instance, funded controlled burns and invasive species control, along with other techniques, to improve monarch butterfly habitat on 2,420 acres in northwest Arkansas.

Other efforts break newer ground.

A team from the Florida Museum of Natural History and the University of Florida has experimented with drones and an AI system to collect information on the extent and quality of the milkweed population. Monarch Joint Venture, too, has been collaborating on an artificial intelligence program called POLLi that researchers say can identify at least 80 percent of the common milkweed stems in an image with 93 percent accuracy. Caldwell said this information will help land and resource managers direct their attention to where it can do the most good.

No one program will restore the monarch population, proponents acknowledge, but they warn that an ESA listing would come with difficulties of its own.

“With a species like the monarch that’s so widespread and has habitat in a lot of different kinds of places, that presents some challenges from a regulatory predictability standpoint that a lot of folks are concerned about,” Caldwell said, “and so even if the population warrants the protection provided by the Endangered Species Act, it comes with some pretty major complications.”