With its iconic orange and black markings, the monarch butterfly is one of the most recognizable species in North America. Monarchs are particularly remarkable because they migrate each year, flying from as far as Canada and across the United States to congregate at a few forested overwintering sites in the mountains of central Mexico and coastal California. These sites are an amazing phenomenon: thousands of monarchs cluster in the trees in California, and millions of monarchs drape large swathes of forest in Mexico.
But over the past two decades, monarch numbers in North America have declined, prompting the U.S. Fish and Wildlife Service to join state agencies, tribes, other federal agencies and non-government groups to identify threats to the monarch and take steps to conserve monarchs throughout their range.
Why are we concerned about monarchs?
For more than 20 years, communities and scientists have been tracking monarch populations, with growing concern as the number of monarchs at overwintering sites has declined. What does this trend mean for the future of the monarch? Is it a genuine decline in the monarch population? If so, is it part of a larger natural cycle, a temporary circumstance, or a result of human impact? Is the monarch at risk of extinction, or might it be in the future?
What threats does the monarch face?
The primary drivers affecting the health of the two North American migratory populations are changes in breeding, migratory, and overwintering habitat (due to conversion of grasslands to agriculture, urban development, widespread use of herbicides, logging/thinning at overwintering sites in Mexico, unsuitable management of overwintering groves in California, and drought), continued exposure to insecticides, and effects of