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Monarch butterflies are missing. What's to blame for their shrinking population.

Monarch butterflies are missing. What's to blame for their shrinking population.
Monarch butterflies are missing. What's to blame for their shrinking population. 03:45

(CBS DETROIT) - Monarch butterflies are well known, but have you noticed they're appearing less? The shrinking population is alarming. 

From 1996 to 2020, nearly 90% of the eastern monarch population has diminished from an estimated 383 million to just under 45 million. With their unique lifecycle, monarchs are essential for our planet to thrive, migrating from central Mexico, and flying to the United States and parts of Canada. During their travels, butterflies lay eggs on milkweed, eventually creating a new generation that relocates farther north. The last generation won't reproduce and will fly back to Mexico for the winter.

Along this migratory life process, monarchs are experiencing habitat loss, with overuse of pesticides, disease and a warming climate all contributing to the drop in population. 

"They're also experiencing threats related to climate change, so they need a very specific kind of temperature and precipitation conditions to develop from an egg all the way into a butterfly, and if those change during certain times of the years, they may not be able to survive quite as successfully or be able to reproduce as successfully," said Elise Zipkin, an associate professor at Michigan State University's environmental science and policy program. 

The milkweed plant is known as the host plant for monarch butterflies. Meri Holm, a wildlife biologist for the U.S. Fish and Wildlife Service, says climate change impacts the butterflies' survival and plants. 

"When you get warmer springs, wetter springs, all this impacts how plants grow and when they grow and when they flower, the phenology of plants," she said. "If there aren't a lot of resources for the butterfly during the certain time of year when they need them when they're migrating. Then that's going to impact the population, if there's not a lot of nectar out there for them at the time that they need it it's going to have an impact on the population, so really the climate change impacting the plants is also impacting the butterflies because they depend on those plants."

Due to the vulnerability of this species, the monarch butterfly is a candidate for listing under the Endangered Species Act. We will know more about this in December 2024.

Conservation efforts are happening in many areas in hopes of restoring the population.

Holm says the Fish and Wildlife program works with various groups in Detroit.

"The city has taken a lot of parks that were underused and we're just lawns and been converting those to a wildflower meadow," she said. "We've been doing that every year for the last eight years to try to connect those habitats. So with other land owners, whether it be a private land owner or a nonprofit, and to make corridors of habitat for pollinators like the monarch butterfly."

There are ways you can help, too. The Detroit Zoo's Butterfly Garden houses many butterfly species. 

Jessica Jozwiak, the Detroit Zoo's bird department supervisor, has tips on helping restore the monarch population. 

"There are things your average person can do, and that is plant milkweed and plant nectar plants in your yard if you can. Work with the local community to make sure they preserve existing habitat for monarch butterflies," she said. 

Despite their small size, monarchs play a critical role in our environment. We rely on our natural resources, like the air we breathe, clean water and our food sources, and monarch butterflies are just one part of that. 

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