It's official, Western Monarchs are back

The Xerces Society added its weighty voice to a chorus of positive reports that the Western Monarchs have rebounded. "In a surprising and remarkable outcome, this winter brought a final tally of 247,237 monarch butterflies observed across the West, an over 100-fold increase from the previous year’s total of less than 2,000 monarchs and the highest total since 2016," the organization reported on January 25.


Here's the full story, which Xerces deemed "surprising and remarkable," as reported on the organization's website.


“We’re ecstatic with the results and hope this trend continues,” says Emma Pelton, the Western Monarch Lead with the Xerces Society. “There are so many environmental factors at play across their range that there’s no single cause or definitive answer for this year’s uptick, but hopefully it means we still have time to protect this species.”

Overwintering sites skew south

Santa Barbara County reported the most monarchs this year at over 95,000, including the largest single site where more than 25,000 butterflies were counted on a private property. San Luis Obispo County came in a close second with over 90,000 butterflies reported at overwintering sites, including the Pismo Beach Butterfly Sanctuary managed by California State Parks, which had the second highest count at an overwintering site this season at 20,871 butterflies.


Typically, California’s central coast hosts the majority of monarchs, as well as a significant number in the San Francisco Bay Area. However, Bay Area sites had few or no monarchs this year, with fewer than 600 butterflies counted at overwintering sites stretching from Mendocino to San Mateo counties.


More monarchs were found starting near Santa Cruz, with over 1,000 at both Natural Bridges State Park and Moran Lake. And in Monterey County, the City of Pacific Grove celebrated the return of approximately 14,000 monarchs to their sanctuary. In Ventura and Los Angeles counties, monarchs were found in numbers unseen since the early 2000s, totaling nearly 19,500 and over 4,000 butterflies, respectively.


Thanks to public tips, this season also included the discovery of five new roosting locations in San Luis Obispo and Los Angeles counties, totaling over 7,000 butterflies.

These totals were observed thanks to a record-high volunteer effort to survey 283 overwintering sites. Supported by regional coordinators, volunteers seek out and record clusters of monarchs as they huddle together for winter warmth.


“I actually had more volunteer counters this year than I have in the last 10 years, because there are so many people who care about monarchs and want to help,” says Jessica Griffiths, the volunteer regional coordinator in San Luis Obispo County. “They were out there at the crack of dawn in the cold, scanning the trees with binoculars. Some of the newer volunteers saw monarch clusters at their sites for the first time this year, which was really exciting.”


Graph of total abundance estimates with number of sites monitored from 1997-2021 (c. The Xerces Society for Invertebrate Conservation 2022).

Rebound offers a ray of hope to ward off extinction

While the 2021 tallies are worth celebrating, western monarchs have undergone a significant decline, losing more than 95% of their population since the 1980s.


“This year’s total is a step in the right direction, but still indicates a severe population decline,” says Isis Howard, Endangered Species Conservation Biologist for the Xerces Society. “Now more than ever, we have an opportunity to double-down on our conservation efforts. Acting quickly to harness the momentum of this upswing is our best chance at preventing western monarchs and other at-risk butterflies from being lost forever.”

Key actions to aid the recovery of western monarchs include protecting their existing habitat and overwintering sites, reducing pesticide use and restoring new habitat by planting nectar plants and native milkweed in the appropriate locations of their range, as outlined in the Xerces Society’s Western Monarch Call to Action.


“Insects can be amazingly resilient if we give them a chance,” says Xerces Director Scott Hoffman Black. “Everyone has a role to play, whether that’s adding pollinator plants and avoiding pesticides in your home garden, or advocating for monarch-friendly policies within our neighborhoods, public lands and plant nursery and agriculture providers.”


The following organizations support western monarch conservation through the Xerces Society:

Bureau of Land Management, California Department of Fish and Wildlife, California State Parks Foundation, California Wildlife Conservation Board, Chantecaille, Google.org, Forest Service International Programs, The Marion R. Weber Family Fund, National Fish and Wildlife Foundation, Natural Resources Conservation Service, San Diego Zoo Wildlife Alliance, The Taggart Saxon Schubert Fund, and US Fish and Wildlife Service, as well as Xerces Society members.

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