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California Overwintering Sites
Nov. – Jan.

The Western Monarch Count is an annual effort of volunteers to collect data on the status of monarch populations along the California coast during the overwintering season, which occurs from approximately October through March. The height of this volunteer effort occurs during the Western Monarch Thanksgiving Count, which runs for three weeks surrounding the Thanksgiving holiday. Thanks to the extraordinary effort of a cadre of volunteers, we now have over 20 years of data demonstrating that monarchs have undergone a dramatic decline estimated more than 95% in the western U.S. since the 1980s (Schultz et al. 2017). This effort has been coordinated by Mia Monroe, Shawna Stevens, and Dennis Frey in the past, and is now coordinated by Mia and The Xerces Society for Invertebrate Conservation.

In January 2017, The Xerces Society and Western Monarch Thanksgiving Count volunteers expanded their efforts to monitor western monarchs for a second period each winter. This New Year’s Count includes a smaller subset of the overwintering sites monitored during the Thanksgiving count period and we could use YOUR help to expanding the number of sites monitored around the New Year’s holiday.

Contact [email protected] or your regional coordinator, or see upcoming trainings at to get started!