Skip to main content

Western monarchs are showing up along the California coast in greater numbers than last year’s historic low.


Expert Contacts

Emma Pelton, Senior Conservation Biologist, Xerces Society for Invertebrate Conservation
[email protected]    |    (971) 533-7245

Sarina Jepsen, Director of Endangered Species and Aquatics Program, Xerces Society for Invertebrate Conservation
[email protected]    |    (971) 244-3727


PORTLAND, Ore.; Thursday, October 21, 2021---Migratory western monarchs are being reported at their overwintering sites in coastal California in greater numbers than last year, with hundreds at some sites and thousands at others, giving hope for the struggling population. These reports are particularly welcome after the population reached an all-time low of 1,914 butterflies last year.

This year’s official count has not yet begun. That will take place with the help of over 100 community scientists during the 25th annual Western Monarch Thanksgiving Count, beginning on November 13. Yet these early reports signal the possibility of a rebound in numbers—at least compared to last year’s historic low.

On October 16th, 2021, over 1,300 monarchs were counted at the Pacific Grove overwintering site; this site did not have a single monarch butterfly during last year’s count. Pismo State Beach Monarch Butterfly Grove and an adjacent site tallied roughly 8,000 monarchs on October 20th, 2021; last year, these sites hosted less than 300 butterflies.

Additional smaller estimates and observations from volunteers and the public have started to pour in from the Bay Area, Santa Cruz, Monterey, Big Sur, Ventura, Los Angeles and elsewhere, with numbers ranging from a few to dozens to hundreds, of monarchs. Altogether, there appear to be over 10,000 monarchs easily accounted for at the overwintering sites.

The low count of fewer than 2,000 monarchs in 2020 followed two years of record lows of under 30,000 butterflies each year. The number counted last year represents a 99.9% decline from the millions of western monarchs that overwintered in California in the 1980s. 

“We are overjoyed that migratory monarch butterflies have not disappeared from the western U.S.,” said Emma Pelton, a senior conservation biologist and western monarch lead for the Xerces Society for Invertebrate Conservation. “These early counts give us hope that, if we all work together, we can still bring western monarchs back.”

The annual Western Monarch Thanksgiving Count is a volunteer-driven community science monitoring project that annually assesses the number of monarch butterflies overwintering at groves of trees on the Pacific Coast of California and Northern Baja. The count is coordinated by the Xerces Society for Invertebrate Conservation and Mia Monroe, count founder and longtime volunteer coordinator. This is the primary way that the status of the western monarch migratory population is assessed.

Why are numbers looking a little better this year? It is likely a combination of factors including favorable conditions on their breeding grounds. Populations of monarch butterflies, like other insects, can fluctuate from year to year, in response to the temperature, rainfall, the availability of food, and other factors. Though we are likely to see increases in the size of the western monarch population this year, it is likely to still be dangerously close to extinction, and there remains an urgent need to address the threats that this butterfly faces.

“The Xerces Society and partners are focused on conservation at overwintering sites, in early season breeding areas and ensuring late season floral resources exist for migrating monarchs,” said Sarina Jepsen, Director of Endangered Species and Aquatics Program at the, Xerces Society for Invertebrate Conservation. “These are the actions that we and other scientists feel are the most important to successfully recover western migratory monarchs.”

Western monarchs continue to lack the legal protection that would usher in resources to help recover the population, but there are many things that can be done to improve their chances. The Xerces Society along with other researchers and partners developed the Western Monarch Call to Action. It provides five key steps that if implemented quickly, can help recover the population. This rapid approach aims to complement long-term plans such as the Western Association of Fish & Wildlife Agencies plan.

There are many habitat restoration projects in progress right now to enhance and restore monarch breeding and overwintering habitat in California, but more are needed. Legislation proposed in Congress including the Monarch and Pollinator Highway Act (now part of the infrastructure bill) and the Monarch Act (which focuses on western monarchs) could provide critical funding for habitat restoration and research, if passed.

Funding for this year’s Thanksgiving and New Year’s counts are provided by the U.S. Fish and Wildlife Service, the San Diego Zoo Wildlife Alliance and Xerces Society members.




Learn more about the Western Monarch Thanksgiving Count:

How can you help Western Monarchs? See the Western Monarch Call to Action:


The Xerces Society for Invertebrate Conservation protects the natural world by conserving invertebrates and their habitat. Established in 1971, the Society is a trusted source for science-based information and advice and plays a leading role in protecting pollinators and many other invertebrates. Our team draws together experts from the fields of habitat restoration, entomology, plant ecology, education, community engagement, pesticides, farming and conservation biology with a single passion: Protecting the life that sustains us. To learn more, visit or follow us @xercessociety on Twitter, Facebook or Instagram.