Western Monarch

Stats & Info


Lucy Egertson, Artist, 12 yrs old

There is no doubt that the beautiful and iconic Monarch Butterfly is in trouble.  Both the eastern and western US populations of America’s migrating marvel have plummeted ten-fold since the 1990s.  However three years ago, things mysteriously got much worse for the western population. 

Western Monarch Population
  • 4.5 Million in 1980s​

  • > Million in 1997​

  • 192,000 in 2017​

  • 20,500 winter 2018!  (About the size of a beehive!​)

  • 30,000 = average “quasi-extinction” size​

Emma Pelton-Xerces blog 11-29-2018

The last entry on the graph above shows what appears to be a very slight increase in the tiny population from 2018 to 2019.  However, the bar graph below illustrates that sadly, that is not the case.  The monarch overwintering population was re-counted a few months later during the New Year’s Count, and the population was reduced by almost a half; the overwintering colonies diminished prior to their springtime migration start.


What is happening?  Can the downward spiral be stopped, or have we reached a critical tipping point?  And it’s not just the monarchs; there is a similar decline in population and health of many of our pollinators.  Could the monarch butterfly be the harbinger of things to come for many of America’s pollinators?

There are many reasons that contribute to the plight of the monarch:

  • Overwintering habitat loss & quality decline

  • Breeding habitat loss throughout the west

  • Feeding habitat loss

  • Pesticide use

  • Climate Change 

  • Disease & parasites

There is no single culprit, but we humans have a huge impact on all of these issues.  That impact can be positive. Or it can be negative.  We advocate for the positive!  And we advocate for that from every state in the west. Our magnificent long-distance pollinators do not stop at state boundaries, nor should our efforts to conserve and restore their habitat.  We need to focus on the whole and do what is needed, where it is needed.

As the graph of the Western Monarch Thanksgiving Count below shows (Xerces, 2020), in 2017 our western population took yet another turn for the worse, dropping another ten-fold in just one season.  That’s more than a hundred-fold drop (99.4%), bringing the entire western monarch population that is counted every year down to a number that is less than the population of honeybees in one beehive!


Click on any of the 7 states below to be taken to that page

Our Western Monarchs:

Western Monarchs have declined by 99.4% since the 1980s.  For every 160 Monarchs there were then, there is only one left today.

Help Us Conserve the

Western Monarch

The U.S. Fish and Wildlife Service received a petition to list the monarch butterfly under the Endangered Species Act (ESA).  Their decision is due December 2020.  https://www.fws.gov/savethemonarch/SSA.html

Important Links

WMA provides and updates the information on these pages as a vehicle to encourage people to seek and interact with each other. We make no representation other than that.  This is not a formal "clearing house" where all information is vetted or approved by another organization or government entity.

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