A summary of the Xerces Society’s Monarch work throughout North America.
The migration of monarch butterflies (Danaus plexippus plexippus) is an awe-inspiring sight that heralds the changing seasons across much of North America. The eastern monarch migration spans the midwestern and eastern United States in the spring, summer, and early fall, Canada in the summer, and the oyamel fir forests of Mexico in the fall and winter. (Fun side note: You can track the monarchs’ progress on our partner Journey North’s website!)
In Mexican tradition, monarchs symbolize the returning spirits of the deceased, and figure heavily in the early November celebration of Dia de los Muertos. Monarchs also draw many tourists annually to the Reserva de Biosfera de la Mariposa Monarca (Monarch Butterfly Biosphere Reserve), a World Heritage Site that houses most of the eastern monarch overwintering sites, in the states of Mexico and Michoacán.
The western monarch migration stretches from southern British Columbia, down to Washington, Idaho, Oregon, Nevada, California, Arizona, New Mexico, and ultimately Baja California in Mexico. A smattering of sightings also occur in Montana, Wyoming, Colorado, and Utah in the spring and summer months. Regardless of where they begin in the West, come November, they all converge on the coasts of California and Baja California to overwinter among the coastal pines until early spring.
Working to Conserve the Iconic Migrations
Sadly, these inspiring migrations have experienced significant declines in the past few decades. Most alarmingly, the western monarch migration—which had an estimated overwintering population of 4.5 million in the 1980s—has experienced a dizzying 99.4% decline and is at risk of disappearing altogether. Thanks to the efforts of community scientists involved with the long-running Western Monarch Thanksgiving and New Year’s Count, the Xerces Society was able to sound the alarm this winter when the population dipped below the threshold for quasi-extinction, releasing the Western Monarch Call to Action in January.
The response has been encouraging, with community members, government agencies, nonprofits, universities, and other entities joining with Xerces to restore and protect monarch overwintering and breeding habitat, conduct research to better understand the obstacles facing western monarchs (more details here), contribute data to community science efforts, and more. However, we are by no means out of the woods, and we encourage you to check out our tips for individuals interested in supporting western monarch conservation for more information.
In the east, the situation is less bleak, but still requires ongoing conservation efforts. This winter was a relatively good one (at least in recent memory), with the amount of overwintering monarchs up by 144% from the previous year, and higher than most recent years. This is cause for celebration, as it gives monarchs a fighting chance at recovery, but we cannot cry victory yet. The area that monarchs occupy in Mexico is still 66% lower than it was in 1997, and the bump in numbers this winter was likely influenced by the fact that 2018 was a great year, weather-wise, for monarchs, with ideal conditions throughout the breeding, migration, and overwintering seasons.
We of course recognize and appreciate the amazing efforts of many organizations and individuals across North America that are contributing to monarch conservation. However, we cannot ignore the fact that weather likely played a significant role in the population increase in 2018. We can (and should!) be encouraged by the success of the past year, but we need to be spurred onward, rather than becoming complacent, assuming that our work is done already.
Indeed, the Xerces Society is continuing its far-ranging work on monarch conservation in the east. It would take several blog posts to cover the breadth and depth of our eastern monarch conservation efforts, so I will stick with highlighting a few recent and ongoing Xerces projects:
- Developing a series of 16 roadside milkweed fact sheets for the lower 48 states (in process).
- Collaborating with the Electric Power Research Institute (EPRI) to research and strategize ways that the electric power industry can support monarch conservation (more information here).
- Our ongoing relationship with the USDA Natural Resources Conservation Service (NRCS) spans myriad conservation efforts, including work on a variety of aspects of monarch conservation. That work includes but is by no means limited to:
- Conducting on-the-ground monarch habitat restoration in several states,
- Developing tools to support monarch conservation efforts, such as the Monarch Wildlife Habitat Evaluation Guide (WHEG), which helps NRCS and Xerces staff to assess which properties are of highest priority for habitat restoration assistance, and
- We have also helped NRCS create monarch plant guides for multiple regions of the U.S. As one of my colleagues, Ray Moranz, said, “These guides are massive, beautiful and full of interesting information, primarily on the nectar plants that monarchs are known to use in each region, but also info on some milkweeds—which are almost always also good nectar plants.”
How You Can Support Monarch Conservation Efforts
Bottom line, both the eastern and western monarch populations require our continued support, and we at Xerces encourage you to get involved in any way that you can. We offer a more comprehensive list of actions individuals can take to support the imperiled western monarch population here, and have a wide array of monarch-related resources for all of North America here, but listed below are some basic actions we do recommend, and two noteworthy actions that we don’t recommend:
- DO: Plant native milkweed species and monarch nectar plants. Check out our Milkweed Seed Finder to locate a vendor of native milkweed seeds and/or plants near you, and refer to our Monarch Nectar Plant Lists for region-specific suggestions. It is important to note that we do not advise planting milkweed near monarch overwintering sites; please refer to this resource for more information.
- DO: Join monarch community science efforts. Community science, sometimes referred to as citizen science or participatory science, is a term for data-gathering efforts in which anyone, regardless of their background, can participate. This allows for greater breadth in data-gathering efforts, and helps to expand scientific knowledge faster! We recommend checking out the following:
- DO: Reduce or eliminate pesticide use on your land and/or in your community. Herbicides can damage milkweed, which is essential to the monarch’s life cycle, and insecticides are not targeted enough to only harm the pest you are after—they also often negatively impact monarchs. We recommend looking into pesticide alternatives, which are explained further on our pesticide program pages.
- DON’T: Plant tropical milkweed (Asclepias curassavica). Because it does not die back in the winter, this non-native species can harbor a protozoan parasite, called Ophryocystis elektroscirrha or OE for short, that causes significant harm to monarchs. Learn more here. This is where our previously-mentioned Milkweed Seed Finder comes in; with this tool, you can search for vendors that carry other milkweed varieties!
- DON’T: Breed, raise, or rear monarchs in captivity. Long story short, this can spread disease to wild populations and weaken the gene pool over time, and is not scientifically proven to help. Read more here. Our other suggestions above have data to support their use as monarch conservation practices, and therefore we recommend directing your energy towards those endeavors instead.
Thank you for everything you do for monarch conservation! It’s a team effort to support this beloved species and ensure that future generations can view their magnificent migrations.
Learn more about the Xerces Society’s Endangered Species Program.