An annual census of monarch butterflies overwintering along California’s coast reveals that populations in western North America are at their lowest point in five years, despite recovery efforts. Volunteers with the Xerces Society’s Western Monarch Thanksgiving Count visited more sites this past year than have ever been counted since the survey began in 1997, yet they tallied fewer than 200,000 monarchs.

“This year’s numbers indicate a continuing decline in the monarch population,” noted Sarina Jepsen, the Xerces Society’s endangered species program director. “Two decades ago, more than 1.2 million monarchs were recorded from far fewer coastal sites, and just last year nearly 300,000 monarchs were observed at almost the same number of sites.” Population estimates at individual sites also suggest that the western monarch population has continued to shrink. Of the 15 sites which have been monitored annually for more than two decades, 11 had lower counts than last year.

“Counts at some of the state’s largest sites were dramatically lower,” said Emma Pelton, conservation biologist with the Xerces Society. “Pismo Beach State Park was down by 38%, a private site in Big Sur was down by 50%, and the Monarch Butterfly Sanctuary in Pacific Grove was down 57%, from 17,100 to just 7,350 butterflies.” The few sites in which monarch numbers remained stable or increased compared to 2016, include Natural Bridges State Park, Moran Lake, and Lighthouse Field State Park, all in Santa Cruz County.

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