..why it's important to study monarch butterflies? (with Isis Howard)

Ever Wonder? / December 6, 2023
Image attribution
Courtesy of Isis Howard
Image attribution
Courtesy of Isis Howard

As we reach the end of the year, the fall migration of monarchs brings ecological and cultural significance to the people of California and Mexico.  Butterflies are a common symbol for life and death in many places and it is believed that monarchs guide the spirits of our ancestors back during the day of the dead better known as Día de los Muertos. But monarch butterflies can tell us so much more.

Ever wonder why it’s important to study monarch butterflies?

On today’s episode I have the honor of chatting with Isis Howard, who works at the Xerces Society for Invertebrate Conservation. Isis is going to explain to us the difference between Western and Eastern populations of monarchs AND she’s going to tell us how scientists tag butterflies! So, join me in my conversation with Isis Howard

Have a question you've been wondering about? Send an email or voice recording to the podcast team to tell us what you'd like to hear in future episodes.


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Karen Arroyo (00:06):

Hello, this is Ever Wonder? from the California Science Center. I'm Karen Arroyo. As we reach the end of the year, the fall migration of Monarchs brings ecological and cultural significance to the people of California and Mexico. Butterflies are a common symbol of life and death in many places, and it's believed that monarch butterflies guide the spirits of our ancestors back home during the day of the dead, also known as Día de los Muertos. But monarch butterflies can tell us so much more. Ever Wonder ... why it's important to study monarch butterflies? On today's episode, I have the honor of chatting with Isis Howard, who works at the Xerces Society for Invertebrate Conservation. Isis is going to explain to us the difference between Western population of monarchs and Eastern population of monarchs. She's also going to tell us how scientists tag butterflies. So join me in this conversation with Isis Howard.

Karen Arroyo (00:58):

Isis Howard, you are an endangered species conservation biologist that works to protect and support the Western population of monarch butterflies, all while managing several community science projects. Isis, welcome to the team. Welcome to the podcast.

Isis Howard (01:13):

Thank you so much for having me. I'm really excited to be here.

Karen Arroyo (01:17):

We're excited to have you. Before we get started with the whole butterfly talk, can you please just tell us a little bit about yourself?

Isis Howard (01:26):

I am a creative at heart, big nature lover, outside of nature and environmental work. I enjoy going on adventures, walks, gardening.

Karen Arroyo (01:39):

Isis, can you tell us a little bit about your role at Xerces Society and what Xerces does overall broadly?

Isis Howard (01:47):

So, the Xerces Society for Invertebrate Conservation is an international nonprofit organization that focuses on protecting the natural world through the conservation of invertebrates and their habitats. Invertebrates are all the creatures that don't have a spine, and our name, Xerces, comes from the now extinct Xerces Blue Butterfly, which was the first butterfly known to go extinct in North America as a result of human activities. My role at the Xerces Society is really focused on Western monarch community science work. So I have the pleasure of kind of bridging the gap between our research and agency partners and the general public, regarding monarch butterfly conservation and protection. And it's such a pleasure to work with everyday people who share that same love of the natural world and kind of inspire and educate them on ways to get involved in protecting monarchs in their own communities.

Karen Arroyo (02:46):

That sounds so fun. When and how did you get involved with monarch butterflies?

Isis Howard (02:52):

My very first experience getting totally captivated with monarch butterflies started when I was really young. I grew up on a five acre farm in Sonoma County, California, and I remember growing up with Monarch butterflies and Swallowtail butterflies swirling around the garden, and they were kind of the big flashy butterflies that I would notice most often. Now that I'm in the field, of course I notice all the little, you know, brown butterflies and, just smaller butterflies flying about too. But those were the ones that really stood out to me as a child. And then as I progressed, you know, through school and into college and decided to get into environmental science and conservation work. I had the pleasure of residing in San Luis Obispo County, California, which is a county that hosts so many butterflies during the fall and winter. San Luis Obispo, Santa Barbara, central coast of California in general, have an incredible number of monarch overwintering sites along the coast. And so when I was getting my Bachelors of Science at Cal Poly, I was able to visit the Pismo Butterfly Grove, and that's where I really fell in love and got excited to dive into studying monarch butterflies. Then in my work with the resource conservation districts in Sonoma County, I was able to focus my career efforts on monarchs and pollinator conservation work. And so that's when I really started bringing my love for pollinators and monarchs specifically into my job focus.

Karen Arroyo (04:36):

Wow, that's awesome. In Michoacán, we also have one of the largest overwintering sites. So it's interesting that you're able to study overwintering sites here along the coast of California.

Isis Howard (04:47):

I love that you brought that up. Can I just say like one of the, I think one of the biggest misconceptions is that all monarch butterflies migrate from like Canada or the United States down to Mexico, and that is a huge population of monarch butterflies in North America. But we also have another population, which is the western monarchs and those overwinter, typically along the coast of California and in Baja California. So we have these kind of two populations, the Eastern and Western monarchs, and the Eastern monarchs will go down to Mexico and the Western monarchs will typically overwinter in California.

Karen Arroyo (05:25):

Now that we're on that topic, can you describe the difference between Western and Eastern population of monarchs? What do you mean when you say Eastern? What do you mean when you say Western?

Isis Howard (05:35):

When I say Western monarchs, I'm talking about the monarchs that breed and overwinter west of the Rocky Mountains, whereas when I mention Eastern monarch butterflies, I'm talking about the monarchs that breed in overwinter east of the Rocky Mountains.

Karen Arroyo (05:52):

Thank you so much. I just wanted to clarify because I was under the impression that both the Western and the Eastern population of butterflies would migrate back down to central Mexico for the winter period. I know that some of the western monarchs do overwinter in the coast, but I believed that most of them would go back down to central Mexico. Is that true?

Isis Howard (06:14):

Most of the Western monarchs will overwinter, along California and Baja California. There's also a couple inland sites, in like Arizona and the Saline Valley of California, but most of the Eastern monarchs will migrate down to Mexico. Now, we do know that there is some mixing of Eastern and Western monarch populations. So tagging efforts, where researchers or community scientists have put little, like sticker, trackers on monarch butterflies before their migration, when people have tagged those monarchs, they have noted a couple different butterflies from each of those Western and Eastern populations kind of mixing in the overwintering zones of Canada and California. That said, typically, and for a majority of Western monarchs, we're actually gonna see them along the California coast.

Karen Arroyo (07:05):

Gotcha. That is very interesting. Can you tell me a little bit about the tagging process? I've heard that scientists and biologists tag butterflies, but when I hear them say, oh, we tag butterflies, I can't imagine what they mean. Like how do you tag a butterfly? What is, what does that entail? What is the process of tagging a butterfly like?

Isis Howard (07:25):

It's really fun. I had the pleasure of learning how to tag butterflies last year, actually, so it's a bit fresh in my mind. Let me start by saying that monarch butterflies weigh less than a gram, typically.

Karen Arroyo (07:40):


Isis Howard (07:40):

So if you imagine a paperclip, monarchs kind of weigh the same amount as a paperclip. So they're not very heavy at all. And when we're talking about tagging them, adding some sort of marker to them, so that we can track where they're going, where they're spotted along their migration journeys, we had to come up with something that was light enough to not interfere with their flight or their nectaring on flowering plants or their reproduction. And so ultimately we kind of went down to basics and realized that a sticker would do the job perfectly well. And so what many researchers do currently is they utilize a very small kind of dot sticker.And they print out the research lab email or phone number as well as a unique identification number on each sticker. And so when a sticker is placed on a monarch wing, basically, folks are netting a monarch butterfly. They're handling the monarch very, very gently so that they don't mess up the monarch wings. And then what they're doing is they're using the heat from their fingers to activate that sticker and they press it just gently on the monarch's wing so that it's visible when monarchs have their wings closed. So when everyday people are out in their yards or gardens and they see a monarch flying by, they can see that sticker while the monarch is sitting there on the flower or at overwintering sites when the monarchs are up in the trees, resting and getting shelter for winter, they can look through binoculars or take a picture with their phone or camera and get that email and that unique identifier code and then send that to the research lab and say, "Hey, I found Monarch H271 in Sonoma County, California, or in LA."

Karen Arroyo (09:40):


Isis Howard (09:41):

At this date and this time, and this is what it was nectaring on. And then the researchers are able to kind of create maps and track the movement of monarchs. And this really helps us track, which habitats are useful. It's what led to us realizing that there was some of that intermixing between Eastern and Western monarchs. I do wanna mention that if anyone's interested in getting involved in a project that involves tagging monarch butterflies, they should look at local universities such as UC Davis, Washington State University or Colorado State University, and ask to be added to a scientific collection permit because currently it's actually not legal in California to handle monarch butterflies, which means touch, put a cage around, raise, rear, etc. We're not supposed to do that with monarch butterflies in California unless we're part of a official research project and are on that permit.

Karen Arroyo (10:42):

Gotcha. So what I'm understanding is that the purpose of tagging butterflies is to keep track not only of their migration patterns or where they're flying to, but also where they breed and where they overwinter and where they, nectar on different flowering plants. Is that correct?

Isis Howard (11:00):


Karen Arroyo (11:00):


Isis Howard (11:01):

Yes, that's correct. And it has also helped us figure out how many miles monarchs can migrate.

Karen Arroyo (11:08):

Wow. How many miles, and correct me if I'm wrong, but it's my understanding that Monarchs can migrate about 2000 miles from Southern parts of Canada all the way to Central Mexico. Is that correct?

Isis Howard (11:21):

So it's possible that they're migrating that long of a distance, but most likely they're doing that giant migration over the course of several generations. And so they've split this up between, you know, three or four generations through the spring, summer, and fall to get down to their overwintering sites. And so monarchs can migrate from, you know, anywhere from just a couple miles to hundreds of miles or maybe even a thousand plus miles. And that's really incredible. Of course, they might be riding wind currents and they're utilizing all those nectar habitats that folks are planting along the migration route through all of North America.

Karen Arroyo (12:04):

That is so interesting. Why do you think it's important to study monarch butterflies and what can we learn from them?

Isis Howard (12:10):

Monarchs are really incredible species to study and learn about because they represent many of the incredible characteristics and some of the biggest issues that are facing our native pollinators today. We consider monarch butterflies a sort of flagship species or an ambassador for pollinators. One of the important characteristics of monarchs is that they play a big role in the web or cycle of life. So monarch butterflies not only serve as pollinators, but they also serve as food for some of our other native wildlife. This might be a little bit of a sad fact, but most monarch caterpillars are actually eaten before they become butterflies. And those caterpillars provide food for a lot of other animals, including other insects, some species of native songbirds and rodents. Research has actually shown that declines in insects are actually tied to the loss of our insectivorous birds as well. So when pollinator species like monarchs are facing hardships or troubles and their populations are going down, we're also seeing declines in our native bird species.

Karen Arroyo (13:23):


Isis Howard (13:24):

So that kind of underscores the importance of conserving and protecting our monarch butterflies and other native pollinators because everything's really connected. And I also wanna mention, you know, another reason that it's so beneficial to protect monarchs and conserve their habitat is the cultural significance of monarch butterflies. So monarchs are really important to many peoples of North America. Monarchs are native to North America, and so they have shaped the experiences and cultures of the folks who've resided in this continent for centuries.

Karen Arroyo (14:04):

That's right, that's right. I love the cultural significance of monarch butterflies because being from Michoacán, means that I grew up, I grew up with monarch butterflies, not only in my backyard, but also celebrating them and embracing them. And, culturally, we believe that monarchs, as they migrate back to central Mexico, they guide the spirits of our ancestors back specifically for the Día de los Muertos because they typically end their migration period, towards the end of October, early November. And that's exactly when we celebrate Día de los Muertos. So, the cultural significance of monarchs in Michoacán, but also everywhere across Mexico is just beautiful. And it's an iconic symbol. And we see it throughout films, we see it throughout books, we see it throughout imagery and it's always going to be a pressing part of our lives, I think. So thank you for sharing that.

Isis Howard (14:59):

I think so too. Yeah. And thank you for sharing as well. And to all the listeners out there, I urge you to pay attention to the monarch images you see around you, whether that's in murals or books or movies, etc. And you'll start noticing that so many of these butterflies are using the monarch butterfly as their symbol. And it could be any butterfly. There's hundreds of butterfly species out there, but monarchs are really prevalent in our culture and societies and towns have created small economies on it. Or folks are asking people to come out to see the butterflies and it's just amazing.

Karen Arroyo (15:36):

In your professional opinion, what challenges are the Western population of monarchs facing today?

Isis Howard (15:42):

Monarchs are facing a number of challenges and my focus with the Xerces Society is mostly focused on Western monarchs. Again, those are the monarchs that are breeding and migrating and overwintering west of the Rocky Mountains. So in terms of the Western monarch population, the monarch population has declined by about 95% since the 1980s when low millions were observed. It's drastic. It's significant.

Karen Arroyo (16:12):

So drastic.

Isis Howard (16:13):

Back in the day, you know, I've heard reports of the numbers of overwintering monarchs on trees causing the branches to dip down or even crack.

Karen Arroyo (16:23):

To break.

Isis Howard (16:23):

Yeah. To break. And we don't see that anymore in the west. So you might be wondering, well, what's causing such a drastic decline? And, you know, we can't say for sure exactly what is causing this. That said, the factors that are contributing to the decline in monarch butterflies include habitat loss. We're talking overwintering habitat and the breeding or migratory habitat, as well as pesticide use, which includes herbicides, insecticides, fungicides, and all that. Climate change is also probably making things harder for monarch butterflies with more severe and frequent winter storms, extreme temperatures and droughts, which might affect the habitat that they rely on and other factors like disease and predation might also play a smaller role as well.

Karen Arroyo (17:18):

What could be done to protect their breeding sites and their overwintering sites?

Isis Howard (17:24):

Everyone can play a role in helping to protect monarch butterflies. Some of the ways that folks can help monarch butterflies include planting native plants that support these butterflies, like native milkweed plants and flowers that support monarchs throughout the seasons. So if you're interested in creating a monarch or pollinator garden, I'd encourage you to one, find out which milkweed species are native to your area. You can do that through websites like ours, xerces.org. The second thing you'll want to do if you wanna help protect monarch butterflies is reduce your reliance on pesticides through eliminating their use around your home, school, workplace, or supporting farms that use fewer pesticides such as organic farms or farms that use integrated pest management. The third thing you can do is join a community science project, to help report monarchs and milkweeds across the landscape.

Karen Arroyo (18:28):

Can you please give us a little bit of information how we as community members and citizen scientists can get involved in the current conservation efforts and projects?

Isis Howard (18:39):

So a couple projects that I'll highlight include the Western Monarch Count, which is run by the Xerces Society, and one of its co-founders, Mia Monroe, who started the Western Monarch Thanksgiving Count in 1997. It's been going on for over 25 years, and it is a volunteer powered community science effort that aims to track the status of overwintering, Western monarchs and their habitat. And I would encourage you to go to westernmonarchcount.org and sign up to volunteer for next season. We leave our volunteer signup form open all year. But we do ask that volunteers register by November 1st to participate in each season.

Karen Arroyo (19:23):

Would you like to share anything else with the listeners that we haven't discussed yet? Or is there anything else you'd like to add?

Isis Howard (19:30):

I really wanna emphasize that monarchs are one of the few species that utilize a number of different habitats. Which is why I mentioned that everyone has a role to play and it's possible for folks in different circumstances, different environments to get involved in protecting the species. Monarch butterflies migrate hundreds of miles across the landscape and they pass through rural areas, suburban areas, and urban areas. So no matter where someone lives, they have an opportunity to plant the nectar plants or get involved in community science or help advocate for monarchs in other pollinators in their communities. And no action is really too small. I mean, even just talking to your friends, your neighbors, and folks in your community about the plight of pollinators and monarchs and how we can help support an environment that is conducive to like thriving ecosystems and diversity and an abundance of these essential creatures is really what we're going for. So even if you can just start small and spark curiosity and interest, that would be absolutely fantastic.

Karen Arroyo (20:49):

Before I let you go, I do have another question. Where can people follow you and your work online?

Isis Howard (20:56):

Thanks for asking that. If people are interested in following the work of the Xerces Society or myself online, you can go to xerces.org, that's x-e-r-c-e-s.o-r-g and find our main website there. You can also check out the project websites that I work on, which are the Western Monarch Count and Western Monarch Milkweed Mapper. Be going to our websites, westernmonarchcount.org, and monarchmilkweedmapper.org. You can find the Xerces Society on Twitter, Facebook, Instagram. Follow us there, sign up for our newsletter. And we hope to see you get involved.

Karen Arroyo (21:40):

Isis, it was so fun talking to you today. Thank you so much for joining us on our podcast. Ever Wonder.

Isis Howard (21:46):

It was such a pleasure. Thanks so much for having me.

Karen Arroyo (21:49):

And that's our show. Thanks for listening. Until next time, keep wondering. Ever Wonder? from the California Science Center is produced by me, Karen Arroyo, along with Perry Roth-Johnson, D. Hunter White, and Jennifer Aguirre. D. Hunter White and Liz Roth-Johnson are our editors. The music provided by Michael Nickolas and Pond5. We'll drop a new episode every other Wednesday. If you're a fan of the show, be sure to subscribe and leave us a rating or review on Apple Podcast. It really helps other people discover our show. Have a question you've been wondering about? Send us an email or a voice recording to [email protected] to tell us what you'd like to hear in future episodes?