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. If you are a researcher using this data, please be sure you periodically check to make sure you have the most recent version of the data.
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 2020-2021 Western Monarch New Year’s Count are now available!
See our blog about this years New Year’s Count! This was the fifth annual New Year’s Count and volunteers visited a record number of sites! A total of 149 sites were surveyed during both the Thanksgiving and New Year’s Count! These two counts are only possible because of the incredible regional coordinators and volunteers that spend countless hours surveying overwintering sites each year. THANK YOU to all that participate in this invaluable community science project! The data from 2021 is available in pdf and excel.
Previous years data: