The Western Monarch Thanksgiving & New Year’s Counts
The Western Monarch Thanksgiving and New Year’s Counts are the product of annual monitoring efforts by volunteer community scientists to collect data on the status of monarch populations overwintering along the California and Northern Baja, Mexico coast (and a few sites from inland areas of California and Arizona). Thanks to the extraordinary efforts of these volunteers, we have 24 years of data demonstrating that monarchs have undergone a dramatic 99.9% decline in the western U.S. since the 1980s.
The data collected by volunteers are compiled and entered into the Xerces Society’s Western Monarch Overwintering Sites Database which also includes many historic counts and survey efforts. Contact [email protected] if you are interested in obtaining a copy of the entire database.
You can download the Thanksgiving and New Year’s data for every year by clicking on the PDF or excel links below. The graph of Thanksgiving count totals and monitoring effort is updated each year.
Results from the 2020 Western Monarch Thanksgiving Count are available!
*Note: The 2020 Thanksgiving Count data was revised with new count data from volunteers on 2/16/2020.
Data Citation: Xerces Society Western Monarch Thanksgiving Count. 2021. Western Monarch Thanksgiving Count Data, 1997-2020. Available at www.westernmonarchcount.org.
Click here for a larger version.
Results from the 2019-2020 Western Monarch New Year’s Count are here!
Figure 1. Monarch abundance at the 117 overwintering sites in California visited during both the Thanksgiving and New Year’s Counts during the 2019 – 2020 count season.
Figure 2. New Year’s Count Data 2017 – 2020.
Previous years data: