Photo by Natalie Lynn Lichtenbert.

November 1, 2024

The Magic of Monarchs: Acting on the conservation opportunity of our lifetime

Every fall, millions of monarch butterflies (Danaus plexippus) journey from Canada and the eastern and central United States to their overwintering grounds in the high-altitude fir forests of central Mexico. The monarch’s spectacular migration–up to 3,000 miles long–has captivated people for generations. Sadly, we now risk losing this amazing migratory event. The eastern monarch butterfly population has reached historic low numbers since the mid-1990s. Climate change, land use practices, and conversion of grasslands are primary drivers that have reduced available habitat, namely milkweed (Asclepias spp.), across the landscape. In response, Illinoisans are working alongside people all across North America to help reverse these trends.

A brown, yellow, green, and orange map of the United States and Central America illustrating the migration pathways of the eastern and western monarch butterfly populations.
Figure 1: A map illustrating the migration pathways of the eastern and western monarch butterfly populations. Each year, the eastern monarch butterfly population travels up to 3,000 miles from its overwintering grounds in the forests of Central Mexico northward to southern Canada. Source: Monarch Watch.

Illinois lies in the central path of the eastern migration flyway (see Figure 1). Across Illinois, monarch butterflies rely on milkweed and other nectar plants they find in grasslands and pastures, on farms, along roadsides and utility corridors, in state parks and preserves, and in gardens and backyards. Recognizing the iconic species and the significance of Illinois’ once-prevalent prairie landscape, the monarch butterfly was named the state insect in 1975. In 2017, milkweed was designated as the state wildflower (there are 24 species of milkweed found in Illinois, several of which are listed as threatened or endangered).

In December 2020, the U.S. Fish & Wildlife Service (USFWS) determined the monarch butterfly was warranted for listing under the federal Endangered Species Act (ESA) but delayed an immediate listing rule due to other priority species at that time. An updated decision and proposed rule is now scheduled for December 2024. The scale and diversity of habitat that monarchs occupy throughout the United States is diverse and widespread, which makes this listing decision unique as compared to other species the USFWS has considered.

The USFWS is currently reconsidering the ESA listing status of the monarch butterfly, taking into account the overwintering population numbers documented since 2020 alongside updated research. In the last four years, the eastern monarch population counts have been either at or below the population levels identified when the “warranted but precluded” determination was made in 2020 (see Figure 2). This past winter saw the second lowest population count ever recorded. While we do not know what the USFWS will propose for a listing status, the continued decline of monarch butterfly populations indicates the species is at risk—potentially endangering the populations themselves, or changing the ability of monarchs to migrate across such large distances.

A yellow bar graph indicating the overwintering population of monarchs between 1993 and 2023, estimated by measuring the area the monarchs occupy at overwintering sites in Mexico. It is clear that the populations are declining.
Figure 2: A graph illustrating the overwintering population of monarchs between 1993 and 2023, estimated by measuring the area the monarchs occupy (in hectares) at the overwintering sites in Mexico. The eastern monarch population is surveyed each year starting in December when monarchs are clustered together. Source: Monarch Joint Venture.

If the USFWS lists the monarch butterfly as threatened or endangered, a federal listing would result in associated regulations prohibiting “take” (e.g., harassing, harming, killing, collecting or trapping) of monarchs. Illinois has its own endangered species law, the Illinois Endangered Species Protection Act (IESPA). Species listed under the federal ESA are automatically listed under the IESPA. Under a state listing, the state reserves the right to add additional measures above and beyond what is required by the USFWS. Whether a state and federal listing occurs, many people are anxious to see what the proposed decisions will be and how they may affect monarch conservation and other land uses.

The State of Illinois has been a committed leader and partner in state and regional monarch conservation efforts for many years. The Illinois Monarch Project was founded in 2016 to help coordinate and further monarch conservation work in the state. In 2018, the Illinois Department of Natural Resources, Illinois Department of Agriculture, Illinois Department of Transportation and the Illinois Environmental Protection Agency signed an agreement to commit collective state resources to support monarch habitat goals. As part of the Midwest regional goal to add 1.3 billion new milkweed stems and other diverse nectar-producing plants to the landscape by the year 2038, the State of Illinois pledged to contribute 150 million of those new stems. Other monarch habitat and conservation goals and objectives are spelled out in the Illinois Monarch Action Plan, which was published in 2020.

One orange, white, and black monarch butterflies rest on a paper certificate with signatures on top of a table with a green tablecloth.
Monarch butterflies witness the signing ceremony of the Illinois Monarch Action Plan in September 2020. Photo by Illinois Department of Natural Resources.

Since 2020, the Illinois Monarch Project has hosted an annual pledge for individuals and organizations to commit to taking actions to support monarch butterflies and their habitat. The voluntary pledges help state leaders estimate progress toward the goals set forth in the Illinois Monarch Action Plan and are used to inform monarch butterfly conservation priorities and practices across the state.

The annual pledge period is open between October 1 and December 31. Anyone can take the pledge. Whether a passionate monarch enthusiast, someone with no green thumb, or an organization invested in environmental stewardship, the annual pledge makes taking action easy for everyone. The pledge form takes less than five minutes to complete, simply indicating which actions are planned for the coming year. Individuals or organizations that pledged last year also have the opportunity to report on any activities they completed in 2023–2024.

The Illinois Monarch Project website also hosts a range of resources to support individuals and organizations in planning and implementing monarch conservation activities. Resources are organized by sector and include planting guides, mowing recommendations, communications and engagement tools, and other technical guidance. The Illinois Monarch Action Plan can also be downloaded from the website.

In addition, there are many other efforts across Illinois that are actively bringing together monarch champions to create habitat and raise awareness.

  • More than 50 mayors and local governments in Illinois have taken the National Wildlife Federation’s Mayors’ Monarch Pledge. In doing so, they commit to creating habitat for the monarch butterfly and other pollinators, while also educating their residents about how to take action at home and in their communities.
  • The Route 66 Monarch Flyway Committee collaborates with public and private partners across the state to protect and enhance existing monarch habitat and establish new habitat within a 66-mile-wide corridor that stretches along historic Route 66 from Chicago to St. Louis.
  • The Nationwide Conservation Agreement for Monarch Butterfly on Energy and Transportation Lands (also known as the Monarch CCAA) enrolls energy companies and transportation agencies in a voluntary program that supports and tracks habitat conservation commitments made on roadsides, pipelines, utility corridors, power generation facilities, and other lands. Nine energy companies and transportation agencies are currently enrolled in Illinois and together they manage more than 146,000 acres of monarch habitat across the state.
  • The Brookfield Zoo Chicago recently launched a new initiative called Partnerships for Pollinators to support the outreach and education goals in the Illinois Monarch Action Plan as well as the Association of Zoos and Aquariums’ Saving Animals from Extinction (SAFE) program to protect, preserve, and restore the monarch butterfly’s habitat during their migration. The Partnerships for Pollinators initiative will host the annual Illinois Monarch Project’s Wings of Dreams Bioblitz, the Start Seeing Monarchs Day Celebration at the Brookfield Zoo Chicago, pop-up pollinator waystations at the zoo, and digital pollinator trading cards.
An orange, black, and white monarch butterfly rests on a green plant. In the background is lush vegetation in a grassland.
Photo by Natalie Lynn Lichtenbert.

One thing is certain: the monarch butterfly continues to garner interest and enthusiasm from a growing number of devotees. People of diverse backgrounds, sectors, and ages are working together with a common goal to help monarchs. In doing so, their actions provide benefits to other species in need as well. Monarchs are the conservation opportunity of our lifetime: charismatic yet accessible, small but relatable, a distant traveler and a familiar visitor. They offer a way to build and bridge a stronger conservation ethic within our communities.

Small or large, do your part. Invite your friends and family to take action as well. Join us in taking the Illinois monarch pledge before the end of the year.


Iris Caldwell is a Principal Research Engineer at the Energy Resources Center at the University of Illinois Chicago, where she supports a variety of initiatives related to sustainable landscape management. Iris served as state coordinator of the Illinois Monarch Project collaborative during the development of the statewide monarch conservation action plan. She also founded the Rights-of-Way as Habitat Working Group, a nationwide network working to enhance habitat conservation along energy and transportation corridors.

Natalie Lynn Lichtenbert has a master’s degree in Conservation Leadership/Zoology and works during the day as a lab scientist. She is a fellow of the esteemed Explorer’s Club and has served as the Deputy Director of the Illinois Monarch Project’s Community Engagement Committee. Being passionate about climate change, sustainability, habitat loss and biodiversity, she speaks at local and international events to help teach people of all ages the importance of conservation and living a sustainable lifestyle. She founded a non-profit organization, Green Dolphin Project Global, with the mission to connect people of the Great Lakes to our great oceans.

Dan Salas is the Director of the Sustainable Landscapes Program at the Energy Resources Center at the University of Illinois Chicago, where he works at the intersection of nature, biodiversity and infrastructure. He leads the Rights-of-Way as Habitat Working Group, including the nationwide conservation agreements for monarch butterflies and bumble bees and a range of research and tools supporting habitat conservation through industry collaboration. He is a certified Senior Ecologist by the Ecological Society of America and decision analyst certified by the U.S. Department of Interior.

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