Citizen Science

The Monarch Butterfly Decline, and What You Can Do About It

April 4, 2013

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Monarch butterfly populations declined 59 percent in the past year. Photo by Kenneth Dwain Harrelson
Monarch butterfly populations declined 59 percent in the past year. Photo by Kenneth Dwain Harrelson

For the past month, monarch butterflies have caused a lot of buzz in both the news and in conservation circles. The reason: a report published by the World Wildlife Fund and others that documented a 59 percent decline in monarch populations this year.

This week, Yale Environment 360 published perhaps the best piece yet on this alarming decline, Richard Conniff’s interview with Chip Taylor of Monarch Watch. It presents a number of interesting issues that conservationists should notice.

It’s well known that almost the entire eastern population of monarch butterflies overwinters in a few clustered forests in Mexico. These tiny islands of habitat make the butterflies vulnerable. Many U.S. residents believe that the population decline is, in fact, due to logging in Mexican forests. But as Taylor points out, the Mexican government has done an excellent job stopping illegal logging.

So why the decline?

The study’s authors point to agricultural fields. Taylor suggests that the monarch butterfly is likely “collateral damage” from the use of genetically engineered crops, namely Roundup-ready corn and soybeans. These crops have resulted in significantly higher pesticide use, wiping out the milkweeds that monarchs need to survive.

As Taylor says in the interview:

Now you are really hard pressed to find any corn or soybeans that have milkweed in the fields. I haven’t seen any for years now because of the use of Roundup after they planted these crops. They have effectively eliminated milkweed from almost all of the habitat that monarchs used to use.

Additionally, due to biofuel and high crop prices, there are more acres in corn and soybean production than any year since just after World War II.  This has meant that a lot of land has been taken out of the Conservation Reserve Program (CRP) and a lot of marginal land–where milkweeds once grew– has been tilled.

That’s a lot of lost habitat for wildlife, including monarch butterflies.

And here’s where you come in.

Taylor’s Monarch Watch is urging people to plant milkweeds as part of their backyard gardens this spring.

Milkweed isn’t going to grow back on agricultural monocultures. Conniff questions whether backyard gardening can really help, but there are a lot of backyards and vacant lots that could hold milkweeds.

As Taylor says: “To assure a future for monarchs, conservation and restoration of milkweeds has to become a national priority.”

And it would appear that similar citizen-led restoration efforts have helped other species: Consider the nesting boxes that have dramatically helped eastern bluebirds and wood ducks, conservation efforts led by birding clubs, youth groups and backyard enthusiasts. A similar effort in planting milkweed could create a lot of butterfly habitat.

Monarch Watch offers milkweed growing tips to get you started, and has information on other citizen-science projects that can help butterflies.

And, please: lay off those those pesticides. Using alternatives for your weed and pest issues not only helps butterflies, it’s better for kids and pets, too.

Monarch butterflies are one of the most charismatic and beloved species in the country. It’s time for all of us to do our part to make sure they remain a common sight in our yards, gardens and parks.

Photo credit: Kenneth Dwain Harrelson under the the Creative Commons Attribution-Share Alike 3.0 Unported, 2.5 Generic, 2.0 Generic and 1.0 Generic license.

Opinions expressed on Cool Green Science and in any corresponding comments are the personal opinions of the original authors and do not necessarily reflect the views of The Nature Conservancy.  

Matt Miller

Matt Miller is a senior science writer for the Conservancy. He writes features and blogs about the conservation research being conducted by the Conservancy’s 550 scientists. He has served on the national board of directors of the Outdoor Writers Association of America, and has published widely on conservation, nature and outdoor sports. More from Matt

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  1. Excellent idea, Matt, but you ought to send out seeds to those who are interested…like me. I would donate a good portion of my yard and all the labor if I had the seeds and the planting tips.

    1. I have several plants of the wild asclepias tuberosa or “butterflyweed”. The seeds aren’t forming yet, but I’ll be gladd to send you some.
      contact me @

  2. I have planted hundreds of milkweed plants. However, I am looking for roundup resistant milkweed seed? Either from observation and collection naturally or otherwise.

  3. I have bred Monarch butterflies in Caulfield Melbourne when they just blew in to inhabit my Dutchmans pipe milkweed and would like to start again

    1. I also live in Melbourne Surrey Hills and have not seen any Monarchs for years. I believe they still exist in some suburbs and am curious to know if the planting of Swan plants would attract them in this area or if anyone in nearby suburbs has them?

  4. We were already planning to build a butterfly/hummingbird garden, and, now, want to be a part of this endeavor to help our Monarch friends!!! Thanks for the info.

  5. Hey Mr. Miller, great article. Here in Michigan we appear to be awash in milkweed, both on fallow land and along our highway rights-of way. But obviously it’s a long way between here and Mexico, and the monarchs are not making it. Is there any work that might focus people’s efforts to the “milkeweed deserts” or areas of greatest need?

  6. Last year I noticed far fewer monarchs than in previous years, and this summer they seem rare. I think much of the early milkweed shoots were been eaten by deer in the habitats that I monitor; some fields are devoid of milkweed (where it previously flourished). A cold wet spring, following a record drought, is my guess for part of the decline.At least in the non-agricultural area where I live there looks to be little hope for recruitment this year. I’m still waiting to see the 1st monarch of the year in my little backyard milkweed patch.

  7. My yard is filled with milkweed. I even mow around the plants that have sprouted in my lawn. I’ve noticed the decline in monarchs over the last few years and, sadly, I have yet to see a single monarch this year. The only thing chomping on the milkweed are those milkweed beetles.

  8. My yard is full of milkweed plants that are being eaten bare by the Milkweed Tiger Moth caterpillars. There are thousands of them. I don’t use pesticides of any kind and this is the first summer that they have taken over. I don’t think there will be enough milkweed left for the Monarchs to survive from the egg stage. I have seen several butterflies on my nectar plants but no eggs or caterpillars so far (on the milkweed). The tiger moth caterpillars have not been as prolific in past years and both caterpillars have survived nicely. Is anyone else having the same problem? We have had a pretty wet summer here and everything is in full bloom. Any comments or suggestions?

  9. I live in NW Vermont, about 15 miles W of the city of Burlington, in the Town of Williston. Though the area is suburbanizing, there are still large tracts of old pasture that abound in milkweed and also in the plants, such as NE Aster, that the adult butterflies feed on. But I have not seen a Monarch this year. NONE. It is heartbreaking. I should mention that changing weather conditions may be playing a role in this decline: we experienced torrential pelting rains in early July. I believe this killed many songbirds and hawks (then on their nests), also drowned rodents and snakes, and, possibly, destroyed insects and some butterflies, including Monarchs. It is heart-breaking to see the fields around here filled with bright asters and other wildflowers favored by Monarchs, but no Monarchs. I look, and look. In vain.

  10. Are there any organized efforts to plant milkweed in Connecticut or Michigan? What is the possibility of interesting state organizations in planting efforts this spring?

    Dick Hasbany

  11. It’s great to feel like we’re empowered to do something for the monarchs, and we should do everything we can.

    But are we all too polite to call “no fair” on the farming practices that are the big driver of the problem? When did we learn collectively to roll over like this? By taking on the problem in our backyards and stopping there, we’re letting the real culprits off the hook.

    So plant milkweed, for sure, but also:

    – Buy organic food, including grass-fed meat. Reward farmers who don’t damage the ecosystems they operate in.

    – Shun biofuels if at all possible. When you ride your bike to work, think of butterflies :-).

    – Write your representatives and express your concern. Ask that future consideration of GM crop regulation factor in collateral damage like this. You could even ask that farmers using roundup-ready crops be required to allocate space to milkweed and other insect-friendly plants.

    I love the idea of roundup resistant milkweed, but then…. arms race?

  12. My gomphophsyocarpa is bearing several thousands seeds. I’m ore than happy to give them to other monarch enthusiasts. All I’m asking is for a self-addressed stamped envelope and I’ll send them right away.

  13. I’d also like to add a theory which is along similar lines as the above. In addition to the impact from pesticides used on crops I guarantee another major reason we are losing the Monarch’s is the fact that people are using pesticides that are not only used on the interior of the home but has become popular to spray the outside of your home in most suburbs. Monarchs like to hang out on homes and siding along their route, if it’s sprayed they are tainted. I’d like to ask for regulations to be in place on the use of these chemicals.