Monarch Butterflies Listed as Endangered

You may have seen reports saying monarch butterflies are endangered. See what experts say about monarch population numbers and how to help.

Are Monarch Butterflies Endangered?

Monarch butterfly with tagCourtesy Jessica Bisko
Monarch butterfly with tracking tag

Monarchs are among the most recognizable and best loved butterflies in North America. But you may have noticed fewer of them traveling through your garden over the last few years. Migratory monarch butterflies recently entered the International Union of Conservation of Nature‘s Red List of Threatened Species as Endangered. The U.S. Fish and Wildlife Service is also assessing whether the monarch butterfly should be listed as threatened or endangered. Here’s what you need to know and how you can help.

Monarch Butterfly Population Numbers

monarch butterfly on liatrisCourtesy Carol Shaffer
Monarch butterfly on liatris

Researchers have split monarchs into two groups at the Rockies: eastern and western. They’re not distinct species, but their migration paths and overwintering habitats differ. One group seems to be more robust and healthy than the other.

According to the IUCN, the western population is at greatest risk of extinction, having declined by an estimated 99.9%, from as many as 10 million to 1,914 butterflies between the 1980s and 2021.

The larger eastern population also shrunk by 84% from 1996 to 2014. Some researchers counted a 144% increase in overwintering monarchs in late 2018, the highest numbers recorded since 2006. Emma Pelton, a conservation biologist leading the monarch programs at the Xerces Society for Invertebrate Conservation, says, “It’s worth celebrating, but we also have to be really cautious that it was a ‘Goldilocks’ weather year.” Conditions in 2018 were just right for monarchs, which may have caused the bump in their numbers, but it will take a few years to confirm whether the butterfly population is actually on an upswing. Eastern monarch butterflies are not out of danger yet.

Why Are Monarch Numbers Declining?

Why are monarch butterfly numbers in such steep decline? Mary Phillips, head of Garden for Wildlife from the National Wildlife Federation, says, “Monarchs are threatened with widespread habitat loss, increased use of pesticides to control insects and weeds, and natural enemies such as predators, parasitoids, and diseases. A changing climate is making some habitat less suitable and forcing changes in migratory patterns.”

Mary further explains that milkweed, the only host plant on which monarchs lay their eggs, used to grow abundantly across the United States.
The best way to help monarchs is restoring their natural habitat by planting native milkweeds and nectar plants, eliminating pesticides and encouraging others to adopt these practices,” she says.

Discover what monarch caterpillars look like, as well as 3 butterflies that look like monarchs.

Reasons for Monarch Optimism

monarch butterfly migrationCourtesy Cari Povenz
Monarchs at Tawas Point State Park in Michigan

There is still reason to hope for West Coast monarchs. The Xerces Society and other organizations with similar goals are pushing to restore and protect overwintering, breeding and migration habitat throughout the West and into Mexico.

“It is difficult to watch monarch butterflies and their extraordinary migration teeter on the edge of collapse, but there are signs of hope. So many people and organizations have come together to try and protect this butterfly and its habitats. From planting native milkweed and reducing pesticide use to supporting the protection of overwintering sites and contributing to community science, we all have a role to play in making sure this iconic insect makes a full recovery,” said Anna Walker, member of the IUCN SSC Butterfly and Moth Specialist Group and Species Survival Officer at the New Mexico BioPark Society, who led the monarch butterfly assessment.

Do monarch butterfly sightings have meaning?

Grow a Garden for Monarch Butterflies

monarch caterpillarCourtesy Cassandra Lowery
A monarch caterpillar crawls across a milkweed leaf

Weather plays a large part in conservation, but there’s plenty gardeners can do to help, too. Planting natives and choosing natural control solutions for weeds and pests go a long way in sustaining the beloved monarch. Insecticides and herbicides are strongly linked to insect and pollinator declines. Here’s how to get rid of aphids on milkweed plants.

All monarchs start their lives on milkweed; it’s the only plant on which adults lay their eggs and caterpillars happily munch. Consider planting one of the many native varieties of milkweed in your pollinator garden to get an up-close view of the monarch life cycle. There are several dozen species of milkweed plants native to North America, and it is important to be sure to know your zone to choose the right one for your region.

Then you can support adult monarchs on their long journey south by growing nectar-rich flowers that bloom from late summer into fall. Try goldenrod, asters and coreopsis. “Adult monarchs feed on the nectar of many flowers, but they breed only where milkweeds are found,” Mary says.

Choose Native Milkweeds

Mary says gardeners should use caution with tropical milkweed (Asclepias curassavica). “This plant, not native to the United States, has become an increasingly popular way to attract monarchs in garden settings. Tropical milkweed is ornamental and easy to grow, and has become one of the most available milkweed species in nurseries. Monarchs happily lay eggs on it. Despite these qualities, when planted in southern states and California, tropical milkweed can encourage monarchs to skip their migration and continue to breed through the winter, potentially putting them at risk for disease and other complications that they would have avoided by migrating. The National Wildlife Federation encourages planting native milkweed and cutting back tropical milkweed in the fall.”

More Ways to Help Monarchs

251125402 1 Kira Macneil Bnb Bypc2020Courtesy Kira Macneil
Monarch butterfly on milkweed
  1. Encourage local leaders to join the Mayors’ Monarch Pledge.
  2. Engage in community conservation actions such as native habitat restoration, education and outreach and local policy changes to benefit monarch butterflies.
  3. Enroll in monarch conservation, community-based science opportunities in local communities.
  4. Reduce or eliminate the use of pesticides.
  5. Create an outdoor space using native plants that attract monarchs and other pollinators. Once you’ve incorporated all the elements of a wildlife-friendly habitat—food, water, cover, and places to raise young—be recognized by certifying your space through Garden for Wildlife’s signature Certified Wildlife Habitat program. Every $20 application fee helps further protect and restore key habitat for pollinators and other wildlife. Every certified garden also counts toward meeting the goals of the Million Pollinator Garden Challenge.
  6. Butterfly Heroes is an initiative that connects gardeners and kids and families alike to help monarch butterflies and other pollinators. By taking a pledge to be a Butterfly Hero, pledgers are committing to create new habitat for monarchs.
  7. It is not imperative to report every monarch in your garden. However, many gardeners like to keep their own records and track how many monarchs they see from one year to another. For reporting, the Western Monarch Thanksgiving Count is the oldest and best. The Xerces Society has been cataloging the rapid decline of monarchs and it’s important to follow their guidelines and suggestions for the count.

Psst—if you’re interested in raising monarch butterflies, here’s what you need to know.

Rachel Maidl
Rachel Maidl is a former senior editor for Birds & Blooms magazine. She enjoys bird-watching in her urban backyard and local state parks, gardening for pollinators and researching new plants. Her favorite backyard visitors are the bumblebees that visit her sedums.