Data


The Western Monarch Thanksgiving & New Year’s Counts

The Western Monarch Thanksgiving Count and New Year’s Count are the product of annual monitoring efforts by volunteer citizen scientists to collect data on the status of monarch populations overwintering along the California coast (and a few sites from inland areas). Thanks to the extraordinary efforts of these volunteers, we have over 20 years of data demonstrating that monarchs have undergone a dramatic decline in the western U.S.

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 wmtc@xerces.org if you are interested in obtaining a copy of the entire database.

You can download the Thanksgiving and New Year’s 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 2018 Western Monarch Thanksgiving Count are now available!

Western Monarch Thanksgiving Count Data 1997-2018 in pdf and excel.

See our Blog and Press Release for the 2018 Western Monarch Thanksgiving Count.

Click here for a larger version.

Results from the 2018-2019 Western Monarch New Year’s Count are here!

See our blog about this years New Year’s Count! Click here for a larger version of the graph below. The data from 2019 is available in pdf and excel.

Figure 1. Monarch abundance at the 130 overwintering sites in California visited during both the Thanksgiving and New Year’s Counts during the 2018 – 2019 count season.

Previous years data:

2018: Click on the following links to read about the second annual New Year’s Count, see the graph, or check out the data in pdf or excel format.

2017: Click on the following links to read about the first New Year’s Count or to see the data in pdf or excel format.