Did the most recent annual count suggest that 99% of Western monarch butterflies have been wiped out?

Tuesday, June 8, 2021
By Jacob Alabab-Moser

Annual counts of Western monarch butterflies in California and northern Baja California by volunteers during Thanksgiving 2020 and New Year's 2021 found that a population decline has accelerated in recent years. The Thanksgiving count—1,914 monarchs—reflected a 99.9% decrease from the 1980s. Counts at specific sites where thousands of monarchs spent the winters past in found only a few hundred, or, in the case of some sites like Pacific Grove, California, none.

The Xerces Society for Invertebrate Conservation, a nonprofit that coordinates the counts, cites habitat loss and degradation, warming and other climate changes, pesticides, and loss of milkweed and other flowering plants as compounding factors in the Western monarch's endangerment.

The U.S. Fish and Wildlife Service and a California state court recently denied monarchs protection under national and state endangered species laws.

This fact brief is responsive to conversations such as this one.
Between 2020 and 2022, under close editorial supervision, Gigafact contracted a group of freelance writers and editors to test the concepts for fact briefs and provide inputs to our software development process. We call this effort Gigafact Foundry. Over the course of these two years, Gigafact Foundry writers published over 1500 fact briefs in response to claims they found online. Their important work forms the basis of Gigafact formats and editorial guidelines, and is available to the public on Gigafact.org. Readers should be aware that while there is still a lot of relevant information to be found, not all fact briefs produced by Gigafact Foundry reflect Gigafact's current methods and standards for fact briefs. If you come across any that you feel are out of date and need to be looked at with fresh eyes, don't hesitate to contact us at support@gigafact.org.