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Western Monarch Overwintering Population Counts Released

Feb 05, 2016


  • Community Science
  • Population Trends

The results of the western monarch overwintering population count have been released! Overall, the results show a slight increase in number of western monarchs since last winter. Many southern California sites had fewer monarchs than the year prior, but more positive news came from the northern range. Previously unrecorded or long-time unoccupied sites hosted monarchs this year, with an increase in numbers at other northern sites.

The small increase in the western population is encouraging and the western population appears to be remaining stable. There is still work to do to ensure we continue moving in a positive direction for monarchs and the conservation of their breeding, migrating, and overwintering habitats. Despite the slight increase in total count, the numbers still indicate a remarkable decline in the overall western monarch population: there are nearly 40% less monarchs than the long term average.

You can get involved by creating monarch habitat, spreading the word about monarchs, and becoming a citizen scientist. Citizen science volunteers across California participated in the Western Monarch Thanksgiving Count, making it possible to know the total number of monarchs overwintering in California.

This information was obtained from the Xerces Society for Invertebrate Conservation. For more information, find their press release here: “Assessment of Western Monarch Butterfly Winter Completed”. Additionally, Candace Fallon, Xerces Endangered Species Conservation Biologist, reflects on the volunteers and program that make this count possible, see blog here.


The content in this article does not necessarily reflect the positions of all Monarch Joint Venture partners.