Monarch butterflies are as American as apple pie, having once been found in backyards across the country. Generations of schoolchildren have reared monarchs in classrooms, watching in wonder as striped caterpillars transform into large orange-and-black adult butterflies. The monarch's multigenerational migration is legendary — a journey of more than 2,000 miles from Mexico to Canada, undertaken by animals weighing less than a single gram.

In monarchs' overwintering groves, there were once so many butterflies that the sound of their wings was described as a rippling stream or a summer rain. Early newspaper descriptions described branches breaking under the weight of so many butterflies and depicted the masses of monarchs as “the personification of happiness.”

Monarch butterfly
These iconic beauties have plummeted by 80 percent in the past 20 years. We're working hard to protect them.
Please help us save monarch butterflies now.


Monarchs play a unique and prominent role in the imagination of our country, especially considering they’re insects. These creatures are ambassadors of nature in people's gardens and symbols of summertime outdoors.

Yet these butterflies, once a familiar sight, are plummeting toward extinction due to landscape-scale threats from pesticides, development and climate change. That's why the Center is working hard to win them protection under the U.S. Endangered Species Act.

Monarchs have declined 85% in two decades. The western population — which overwinters in California as part of its international migration — has suffered a heartbreaking 99% decline. Overall the migrating populations are less than half the size they need to be to avoid extinction.

Monarchs are threatened by pesticides — including toxic neonicotinoids and herbicides, which are killing off the milkweed plants they need to survive — as well as urban development and climate change.



We took our first big action for monarchs in August 2014, when the Center and allies petitioned to protect monarchs as "threatened" under the Endangered Species Act. That December the U.S Fish and Wildlife Service declared the species may warrant protection, triggering an official review of the butterfly's status that, by law, was required to be completed within 12 months. Since by March 2016 the Service still hadn't issued a final decision, the Center for Biological Diversity and Center for Food Safety filed a lawsuit, which resulted in a legal settlement requiring the agency to decide on protection.

Unfortunately the Service's decision, finally announced in December 2020, was that monarchs’ protection was "warranted but precluded" — meaning that although its scientists found that they needed Endangered Species Act protection, that protection was being postposed indefinitely, with no safeguards for the species in the meantime.

And this beautiful butterfly is still declining. With the monarch population well below the threshold at which government scientists predict the migration could collapse, in March 2020 the Center and more than 100 other groups called on Congress to significantly increase funding to $100 million per year to help conserve monarch butterflies and their habitat.

Monarchs' decline is a harbinger of widespread environmental change. The plummeting population of this familiar butterfly, along with the decline of many other butterflies and bees, threatens the wellbeing of people as well, because the food security of humans is dependent on the ecological services that pollinators provide.  History shows a tragic record of the unexpected decline of abundant and widespread species. Complacency and false-positive assumptions about the resiliency of once-common species can have tragic consequences when we don’t take timely action to safeguard their populations.

The Center is also working hard to save monarchs (and all other native pollinators) from pesticides like glyphosate and dicamba through our Environmental Health program.

Check out our press releases to learn more about the Center's actions for monarch butterflies.

Monarch butterfly photo courtesy Flickr/Debbie Long.