Bright orange with black and white markings, the Monarch butterfly is one of our most charismatic insect species. Monarchs are among the few insects that migrate, and the way they migrate is one of the most fascinating among all animals. Weighing less than a paper clip, with a wingspan of only four inches, generations of monarchs fly hundreds to thousands of miles south each autumn. They over-winter in Mexico, Florida and southern California, before making the voyage north each spring. Last year’s winter count of Monarchs was the lowest since record keeping began 20 years ago. Scientists fear the number could be even smaller this year. In this month’s Environmental Outlook, Diane and her guests discuss why the monarch population is shrinking and how we can help preserve their habitat.


  • Rick Borchelt Science writer and amateur naturalist, and director for communications and public affairs, U.S. Energy Department Office of Science.
  • Karen Oberhauser Professor, University of Minnesota Department of Fisheries, Wildlife and Conservation Biology, and 2013 White House Citizen Science Champion of Change Award winner.
  • Tamie DeWitt Invertebrate biologist, Smithsonian National Zoo.

Diane Rehm Tags And Releases A Monarch Butterfly

Smithsonian biologist Tamie DeWitt shows Diane how to hold, tag, kiss good-bye and release a Monarch butterfly.

Google Earth Tour Of The Monarch Butterfly Migration


  • 11:06:51

    MS. DIANE REHMThanks for joining us. I'm Diane Rehm. Former President Jimmy Carter recently called the Monarch butterfly an ambassador of peace. Its extraordinary migration unites the three countries of North America and the decline of its population draws attention to ecological challenges throughout the continent.

  • 11:07:14

    MS. DIANE REHMJoining me for this month's "Environmental Outlook," Tamie DeWitt, an invertebrate biologist and Monarch expert, Rick Borchelt, a science writer and amateur naturalist who works for the U.S. Department of Energy and from the studio at Minnesota Public Radio in St. Paul, Karen Oberhauser, a conservation biology professor at the University of Minnesota.

  • 11:07:42

    MS. DIANE REHMI invite you to be part of the program. Your comments and questions are always welcome. Join us at 800-433-8850. Send us your email to Follow us on Facebook or send us a tweet. And welcome to all of you.

  • 11:08:09

    MR. RICK BORCHELTGood morning, thank you, Diane.

  • 11:08:10

    MS. TAMIE DEWITTThank you, very glad to be here.

  • 11:08:10

    REHMGood to have you with us. And Tamie, as a member of the Washington Area Butterfly Club, tell us about the Monarchs. What is it that makes them so extraordinarily special?

  • 11:08:27

    DEWITTOh, that's such a great question. Just looking at them, they're just so beautiful. They're big, especially the migrating generation right now, they're very, very strong butterflies. They're not the type of butterflies that you always hear your parents tell you, don't touch it...

  • 11:08:40

    REHMYeah, right.

  • 11:08:44

    DEWITT...the scales are going to come off. I mean, we catch them and we hold them and we put tags on them. We'll talk about that later. But it's a phenomenon that they fly thousands of miles, stay down in the mountains of Mexico where it gets quite cold. They stay there for months and months and months in a diapause and then they fly all the way back up to Texas.

  • 11:09:08

    REHMI gather you spent last week counting and tagging Monarchs in Cape May, N.J. Tell us about that.

  • 11:09:15

    DEWITTYes, it was wonderful. I went with a group. I took a group up there of 17 people and it was really a positive experience. When we talk about, you know, the environment and climate change and, you know, it can be so depressing. But actually we met, you know, with a naturalist up there who gave us a talk.

  • 11:09:37

    DEWITTThere are things that we can do and I'm so excited. I've got a little, you know, energy back that I think I was, you know, getting a little...

  • 11:09:42

    REHMYou were getting depressed?

  • 11:09:44

    DEWITTA little bit about that, right. And he's showing us there are things we can do. We can plant in our own gardens. Cape May is so butterfly-friendly and...

  • 11:09:55

    REHMMilkweed, milkweed.

  • 11:09:58

    DEWITT...bird-friendly. Oh, yes. And not only milkweed, which is the host plant that the Monarch needs to lay her eggs on, migrating butterflies need nectar plants so it's also nectar plants. The Monarchs, as they're flying down to Mexico, stop to drink and they actually gain weight.

  • 11:10:18

    DEWITTThey fly thousands of miles and they can actually gain weight on their way down.

  • 11:10:20

    REHMTamie DeWitt, she's an invertebrate biologist. She is a member of the Washington Area Butterfly Club. Rick Borchelt, I know you've recently completed a butterfly big year for the State of Maryland. What does that mean?

  • 11:10:46

    BORCHELTSo many people, I think, are probably more familiar with bird big years where you try to count as many different species of birds in a given geographic area, in a year and sometimes sort of in a friendly competition with your colleagues. For Maryland, it was really an experiment in trying to figure out what kinds of butterflies we still have left in Maryland.

  • 11:11:05

    BORCHELTThere are about 150 different kinds of butterflies that you could potentially see in Maryland. Many, many of those, about 30 of those, have been seen only once or are now extirpated. They no longer exist in Maryland. They're extinct here.

  • 11:11:23

    BORCHELTThey may be in other local states. Just this last weekend, my colleagues and I got my 105th this year. A hundred was a stretch goal for us. We got our 105th and it was Bronze Copper down on the Eastern Shore, a beautiful little butterfly.

  • 11:11:34

    REHMAre there Monarchs in every state?

  • 11:11:41

    BORCHELTThere are Monarchs in every state and not just in North America, either. There are now Monarchs that are established in the Canary Islands, in the Azores, in New Zealand and in Australia. In those last two countries, they're called the Wanderers.

  • 11:11:55

    BORCHELTThe ones in the Canary Islands and the ones in the Azores, most of them probably get replenished every couple of years when butterflies on their way south from the east coast get blown across the Atlantic toward the Azores.

  • 11:12:08

    REHMThey are so beautiful. I did, when I had a garden, had lots of milkweed in that garden to attract the Monarchs. Tell me about tagging Monarchs, Tamie.

  • 11:12:25

    DEWITTGreat, I will. I also wanted to add something about, are there Monarchs in every state? And this does have to do with the tagging. West of the Rockies there are approximately about a million Monarchs in California.

  • 11:12:39

    REHMWest of the Rockies?

  • 11:12:39


  • 11:12:39


  • 11:12:40

    DEWITTAnd they go to places like Pacific Grove and Santa Cruz. That's their migration. It's not a really large migration in comparison to the Monarchs, which we hope are hundreds of millions of Monarchs east of the Rockies.

  • 11:12:54

    DEWITTAnd that's very important. Those are the Monarchs that we tag. So we have these little Mylar tags and they come through an organization that's very important called, We buy the tags. They're very small, smaller than a dime, very, very thin.

  • 11:13:15

    DEWITTYou catch the Monarch with a net. It's a lot easier than you think because as I told you before, these Monarchs are very focused on getting to Mexico. You can literally walk up to a Monarch nectaring. They're so focused that you can snatch them with your fingers and put a tag on them.

  • 11:13:33

    DEWITTOn really good years when you go to places like Cape May or Point Lookout in Maryland where they're roosting in the evening, there can be hundreds or thousands of them and they're all coming in for the evening to roost.

  • 11:13:47

    REHMDoes it not in any way damage that fragile wing to tag them?

  • 11:13:51

    DEWITTThat's a wonderful question. We have come so far. Years ago, 20 years ago, I used to literally use a bottle of glue and some tags.

  • 11:14:02

    REHMOh, my gosh.

  • 11:14:04

    DEWITTWhen they first started, people were using grocery label tags, you know, price tags on them. And then, we were doing it where we were scrapping some of the scales off...

  • 11:14:14

    REHMI see, I see.

  • 11:14:15

    DEWITT...of the butterflies which we didn't like doing. And now they've just developed these wonderful lightweight tags.

  • 11:14:21

    REHMSo let me just tell our listeners that at the end of this program, we're going to go outside. Tamie and I and our other guests are going to go outside our new media center here at 4401 Connecticut Avenue in Washington. I am going to tag a Monarch and then let that Monarch go.

  • 11:14:52

    DEWITTYou have to give it a kiss first.

  • 11:14:54

    REHMYou have to give it a kiss. What do they feel about being kissed?

  • 11:14:59

    DEWITTYou know, I have started this tradition, especially with children at different places where I do these things. They just love it so much, the children do. And being able to do that, I tell them they're going to fly thousands of miles and they're going to be, you know, up in the mountains in the wintertime in Mexico so don't you want to give it a kiss? And it just really makes that connection.

  • 11:15:20

    REHMRick Borchelt, what does tagging Monarchs do? How does that help us understand not only their flight path, but their behavior?

  • 11:15:34

    BORCHELTSo it's very important to sort of figure out where Monarchs are at any time and where they end up, where they're seen. And a lot of times you'll see the tags showing up not just in their wintering site, which for eastern butterflies, eastern Monarchs, they almost all over-winter in Mexico. A very, very, very small amount stay on the trees in Mexico where almost all these hundreds of millions of butterflies...

  • 11:15:57

    REHMThey go back to every year.

  • 11:15:57

    BORCHELTThe same place every year and very, very, very close proximity. They can only stand temperatures that are above freezing. They can stand below freezing very, very little. But if they're exposed to freezing temperatures for any substantial length of time, they will die. So they need to go far enough south where they're not going to be frozen.

  • 11:16:18

    BORCHELTThat's particularly true for the caterpillars. Caterpillars are very sensitive to freezing. But to be able to tag them and see where they end up and see how many butterflies actually make this journey from the ones that start to the ones that make the journey, we can extrapolate sort of how many are successful.

  • 11:16:34

    BORCHELTSo we know how many are leaving Canada, leaving the Northern provinces, leaving the Northeast and ending up in Mexico. That gives us a sense of how difficult that journey is for them. It's not really true that they fly that far south. Tamie and I were just talking. Really, they float that far south.

  • 11:16:49


  • 11:16:50

    BORCHELTThey don't. One of the reasons they're able to gain so much weight is they're not really flying. They are floating on...

  • 11:16:53

    REHMHow much weight do they actually gain during this process?

  • 11:16:59

    BORCHELTThey either stay stable or they can gain up to about a half their body's weight again...

  • 11:17:03


  • 11:17:03

    BORCHELT...depending on what the nectar supplies are like before they get to Mexico. And one of the reasons they get in these huge roosting conglomerations is because it keeps the temperature just a little higher for them. And you would think, with all these butterflies in one place, all they'd be thinking about is mating and getting together with each other. But in fact, one of the things that's fascinating about the southward migration, they're not sexually mature yet.

  • 11:17:28

    BORCHELTAs soon as the daylight starts to decline, the number of hours of daylight starts to decline, their sexual maturity shuts off. During the early part of the year, they can think of nothing but food and sex. Coming back down, they're completely sexless.

  • 11:17:40

    REHMTell me why we should care about Monarch butterflies.

  • 11:17:48

    BORCHELTSo there are a couple of reasons why Monarch butterflies, to me, are really important indicators both of our environment, and that’s one reason why we care, because they show so many things that are going wrong with the environment and some things are going right, by the way.

  • 11:18:04

    BORCHELTBut also because of their importance to understanding what's happening with other pollinators and other species and because I think they strike a chord with so many people, with this migration. It's probably the most complicated, invertebrate migration we know of and understanding those migration patterns help us understand how many, many other animals, birds included, are migrating and how they work.

  • 11:18:29

    REHMRick Borchelt, he's a science writer and amateur naturalist. He works for the U.S. Department of Energy. He writes the blog Lep Log. And short break here. We'll be right back.

  • 11:20:01

    REHMAnd welcome back. In this hour we're talking about the Monarch butterfly. We have two guests with us, Tamie Dewitt. She's an invertebrate biologist. She is a member of the Washington area butterfly club. Rick Borchelt is a science writer and amateur naturalist who works for the U.S. Department of Energy. We have a link on our own site to his blog, which is called Lep Log. We are having a little difficulty getting in touch with our third guest Karen Oberhauser, professor in the Department of Fisheries, Wildlife and Conservation Biology at the University of Minnesota.

  • 11:21:00

    REHMAnd that's particularly sad this morning. She is a 2013 White House Citizen Science Champion of Change Award winner. We will continue to try to get her on the line. When we talk about these Monarch butterflies, I wonder how long we've been keeping records of them and what you are seeing in the way of lower numbers, Rick.

  • 11:21:38

    BORCHELTSo it's important I think, as Tamie started to point out, that we really are talking about three distinct populations. There's the western population. And the dynamics of that population have been known for a pretty long time that migration isn't very long. And you can sort of figure out where those butterflies are headed from. The east coast population, almost all of them go from the eastern part of the United States, that is east of the Appalachian chain and end up in Mexico. However, some of them end up in Florida. We don't know how many.

  • 11:22:09

    BORCHELTSome have been picked up in Florida and we think some may actually be able to make it back from Florida in years when you don't get hard freezes in Florida. But the bulk of them come through the great Midwest. And those have been studied now for a good 30 years more or less. But as Tamie notes, the technology of being able to mark and recapture those butterflies has really come a long way. You can even get them out with little antennae now to sort of track their migration. You can -- some folks have been doing that as well.

  • 11:22:39

    BORCHELTSo we're learning a lot more about that and about where those butterflies -- how fast they travel, where they travel and how they float with prevailing winds.

  • 11:22:47

    REHMAnd now I'm pleased to say we can welcome Karen Oberhauser to the conversation. First Karen, congratulations on the award you received earlier this year. Tell us why you decided to focus on the Monarch butterfly.

  • 11:23:11

    DR. KAREN OBERHAUSERWell, I started studying Monarch butterflies when I was a graduate student in the early 1980s. And I originally started studying them because I was studying paternal investment in offspring. So I was interested in how males invest in their offspring, which for women is kind of an interesting thing to talk about.

  • 11:23:29

    REHMHuh, yes.

  • 11:23:31

    OBERHAUSERAnd it turns out that male butterflies transfer nutrients to females when they're mating. And I started studying Monarchs just because they were very easy to work with in the lab and because they transfer these nutrients to females during mating. But as my career developed and I started having graduate students, I became much more interested in kind of the big picture of Monarch biology. And for about the last 15 years I've been focusing on conservation.

  • 11:24:00

    REHMSo I gather you'll be giving the keynote speech at an international Monarch symposium in Mexico this week. What's the message you want to deliver?

  • 11:24:15

    OBERHAUSERWell, the main message of my talk is that Monarchs have a very complex and interesting life history. And people are very interested in Monarchs because of this life history. Despite this interest, Monarch numbers are declining and we have a lot of data coming in from many places showing that the numbers are declining. I'll talk about some of the reasons for the decline, but the main message that I'll try to give is that we need to act to conserve Monarchs. And that we need to maintain hope.

  • 11:24:47

    OBERHAUSERI'm a conservation biologist and conservations biology, I think, is, above all, a field of hope. So I'm trying to say that there are things that we need to do, but there is reason because people are so interested in Monarchs that we have a lot of reason to hope that we'll be able to preserve their migration.

  • 11:25:07

    REHMTo what extent do you think the ordinary homeowner or gardener can help in this endeavor?

  • 11:25:18

    OBERHAUSERThere's a lot that individual people can do. Any place that's now currently in a lawn or currently in nonnative purely ornamental plants could be turned into Monarch habitat. So we're lucky in the United States and Southern Canada that Monarchs use a wide range of different kinds of habitats. So we can really make a big difference by planting the things that they need. And that would be the milkweed plants that their caterpillars eat and the nectar plants that the adults need to fuel their several-week lives.

  • 11:25:57

    REHMInteresting that we've got one caller who has in the past participated in this very action of tagging butterflies. Let's open the phones and go to Faith in Warner, N.H. Hi there, Faith.

  • 11:26:19

    FAITHHi, Diane. Thank you for taking my call. First time caller.

  • 11:26:21

    REHMSure. Tell us your story.

  • 11:26:25

    FAITHWhen I was a young girl in the mid '60s in Massachusetts, I found a butterfly on the ground when I was riding my bicycle. I carefully picked it up and brought it home. And my father showed me how to make it sugar water nectar. And we fed the butterfly. It flew around our house for a few days. And then I told my teacher at school -- I was in second grade then -- and she had somebody come from Harvard University and they banded the butterfly. This would've been maybe 1964 or '65. She told us about the butterflies and we let this Monarch go out the window.

  • 11:27:04

    FAITHAnd then the school bell rang and all the children -- out of school to walk home. And when I got a few steps out of the school, the butterfly came back and flew on my shoulder. And I never forgot that. And I brought it back to my teacher and said, look, the butterfly came back to me, and hoe come it didn't fly and land on someone else's shoulder? It had the little band on it and it was just magical.

  • 11:27:29

    REHMAnd what happened to the butterfly?

  • 11:27:33

    FAITHWell, I brought it back into my classroom and we let it go again out the window and that was it. I never saw it again but I've never forgotten that story and it was almost 50 years ago.

  • 11:27:43

    REHMOh, isn't that wonderful? Great story.

  • 11:27:46


  • 11:27:47

    REHMAnd what do you think of that, Tamie?

  • 11:27:50

    DEWITTI love it. And I feel like it is magical. And getting these people out there to tag -- when you get that net in your hand and you're not just netting a regular butterfly. You're netting something that's strong and you're doing it for science and you're putting that tag on it. Just this weekend we had some teenagers with us. And it's just so much fun and you're doing something for such a good cause.

  • 11:28:16

    REHMSo the question becomes how long have we been working at this tagging butterflies, Rick, and keeping these records?

  • 11:28:27

    BORCHELTBoth Tamie and I remember the early days of tagging when the tags were very large. And that's been a good 30 years now that we've been working on this. And some actually were tagged even before then. But it was difficult finding -- being able to recover them because we didn't really know where the wintering sites were until relatively recently. And that's what tagging's allowed us to do is figure out where those butterflies come from and where they end up.

  • 11:28:51

    REHMAnd I wonder if we have any idea, Karen, how these butterflies communicate, how they know where to go.

  • 11:29:04

    OBERHAUSERWell, that's a really excellent question that we get asked a lot. And I think that there are kind of two ways to answer that question. We can think of it on a very big picture. We know how Monarchs can navigate, how they know how to fly south, for example. And they do that by looking at the sun. They know what time of day it is. And they can know if they want to go south in the morning they should keep the sun on their left and if they want to go south in the afternoon they should keep the sun on their right.

  • 11:29:33

    OBERHAUSERSo while we know kind of the large scale details of their migration, we don't know the small scale details. We don't know how they find those relatively small overwintering sites in Mexico. And that I think is one of the reasons that Monarchs still continue to fascinate people is there still are all of these unanswered questions. And I think Faith's story, I love that story because Faith, if you were in second grade in 1964, we're exactly the same age.

  • 11:30:03

    OBERHAUSERBut that story really illustrates a strong connection that people have to Monarchs. And it's because of that connection that so many people have scientists and citizen scientists that will be able to answer these kinds of questions. And also maintain people's interest so that we can conserve the Monarch.

  • 11:30:23

    REHMDo you have any thoughts as to why that Monarch would come back to her and sit on her shoulder?

  • 11:30:34

    OBERHAUSERNo. That would probably be a question for the philosophers...

  • 11:30:41

    REHMIt really does seem as though the life of these Monarchs is very risky. I mean, if you start with a certain number, say thousands, heading down to Mexico, how many are we losing in the process, Rick?

  • 11:31:02

    BORCHELTI don't know the exact numbers on that. I'm not sure that we know that for sure. Karen might actually be able to chime in on that one. What we do know is that it is a very risky proposition. And it's risky for so many, many reasons. One reason it's risky is because of weather patterns and extreme weather events. One of the reasons we think that there was such a low turnout of butterflies flying north this year was because of great stretches of drought across their northward migration area.

  • 11:31:29

    REHMAnd how would that drought affect them? Plant life and the like?

  • 11:31:34

    BORCHELTSo the interesting thing about Monarchs is that they have several generations going north. One butterfly goes part of the way north, lays eggs, caterpillars grow, hatch into new butterflies who go farther north. And that can be three or four generations going north. Going south it's all one generation. The same butterfly goes from Canada to Mexico, same butterfly. And that's fascinating to us, that four generations versus one generation.

  • 11:31:59

    BORCHELTBut that means that if you interrupt one generation going north from Mexico, you can create some real population stress on that population. And I believe that's what's happened in the Midwest this year. Even in the east we had -- many of us who are watching butterflies, not just Monarchs but butterflies in general, we had a relatively poor butterfly year because of some very late frosts well into the south. And we think that wiped out a number of the first generation of migrants that were coming north from a number of other migratory butterflies.

  • 11:32:29

    BORCHELTAnd there are a number -- surprisingly large number of other butterflies that are migratory, too.

  • 11:32:32

    REHMRick Borchelt. He's a science writer and amateur naturalist who works for the U.S. Department of Energy. And you're listening to "The Diane Rehm Show." Rick, does the movement of the butterfly have anything to do with your work at the Department of Energy? Does it make you think in different ways?

  • 11:33:05

    BORCHELTIt makes me think in different ways because all we're talking about here all day today is what does basic research tell you about the lives of butterflies and about the environment around us and the stresses in the environment around us. And those of us who work in federal agencies in basic research know that's a fundamental driver of our knowledge. It's a fundamental driver of our economy. Basic research is critical whether it's about Monarch butterflies, whether it's about basic energy, whether it's about atomic nuclear energy.

  • 11:33:32

    REHMAnd, Karen, let me ask you of those butterflies who come down from Canada to Mexico, do we know how many we lose in the process?

  • 11:33:49

    OBERHAUSERNo. Like Rick said, we really don't know the answer to that question. We do know that it's variable from year to year. And, like Rick said, it's really going to depend on the conditions that they encounter during that process of moving south. So if they're moving through an area that's been drought stressed all summer, there won't be as many nectar plants available to them, so they won't be able to get the energy to fuel their flight.

  • 11:34:13

    OBERHAUSERAnd I think it's really going to vary with where they start. So while we kind of picture this map of butterflies starting in Canada and going south, they're really coming from a large range that includes a lot of the United States as well. So the butterflies that have a shorter trip are probably more likely to make it, the butterflies that happen to go through areas where there's been rain. So it's going to be very variable from year to year.

  • 11:34:43

    OBERHAUSERThe reason that we can never really count what percentage make it is that once they get there we only estimate the number of Monarchs by the area they cover. And we might be orders of magnitude off in the actual number of Monarchs that are in Mexico.

  • 11:34:58

    REHMAnd here's a message on, pardon me, Twitter from Matt who says, "If we do nothing to stop climate change, will the Monarch go extinct and how quickly?" Tamie, any thoughts?

  • 11:35:18

    DEWITTThat's a very interesting question. Rick and I actually were talking earlier. Monarchs that migrate down to Mexico hang on one kind of tree, an oyamel fir tree. The Monarchs, the smaller migration in California, they roost on eucalyptus trees. And, as Rick was explaining that those aren't native trees. Maybe our Monarchs could change the trees that they hang on. And it's not only, you know, the environmental. It's the humans that are, you know, helping push that along. Logging up in their roost areas, in their reserves in Mexico up in the mountains, they can't cut down the fir trees, the oyamel fir trees but they can cut down what we call the insulating trees around it.

  • 11:36:14

    DEWITTThe Monarchs cannot live any part of their lifecycle in freezing weather. When we say they go to Mexico, they're not drinking margaritas in Cancun. They are two miles up in the mountains. That's why it took so long to find them. When you were asking about how long this research has been going on, I think it was 1975 or 1976 they were actually found -- there's a beautiful IMAX movie. It's at the natural...

  • 11:36:43


  • 11:36:44

    DEWITTOh, my gosh.

  • 11:36:45

    REHMI've seen that.

  • 11:36:46

    DEWITTI've seen it four times, I've cried every time. It's spectacular. And Urquhart, you know, really dedicated his life to this. When they were found it really is just a phenomenon. So if we don't -- which we are doing now -- protect the areas the best we can, maybe there will be a switch where they can go to different areas. But, you know, that's -- it's just not worth risk.

  • 11:37:12

    REHMTamie DeWitt. She's an invertebrate biologist. And she's a member of the Washington area butterfly club. Short break here and when we come back we will open the phones. And don't forget, shortly after noon we're going to tag a butterfly right here at 4101 Connecticut Avenue. I hope you'll join us.

  • 11:40:02

    REHMAnd we're going to go right to the phones. First to Battle Creek, Mich. Lenny, you're on the air. Oh, dear. Let's see if we can get Lenny on the air. I think we're having a little problem there. Let me see if I can summarize this very quickly. Lenny says he usually sees Monarchs and there's milkweed growing around. But somehow this year there weren't any Monarchs. Is it part of some problem or is it related to his specific area, Tamie?

  • 11:40:46

    DEWITTWell, that's the big question and the big problem. You can do things in your own garden. You can plant milkweed. It's not only -- we need to change the name to milk flower or something and get rid of -- I think people think milkweed is a ragweed and it causes allergies. And milkweed -- there's several different kinds of milkweed and it's so beautiful. You can plant it in your yard. You can plant nectar plants in your yard.

  • 11:41:15

    DEWITTYou can get your own garden certified through It's so easy. I mean, even the National Zoo has their garden certified. It's, you know, not using so many pesticides. You can do things every day, but Rick had a really good point about larger agriculture.

  • 11:41:35

    BORCHELTYeah, I think that there are two things to keep in mind here. One is that one year does not a trend make. And we've seen good flights recently. We've seen poor flights recently. This is going to be a very poor flight, we think. But it doesn't mean that, you know, the butterfly is about to become extinct. We want to assure everybody of that, but it causes some concerns. But one of the issues is the intensification of agriculture in the Midwest where most of the Monarchs are coming from.

  • 11:42:03

    REHMOh, I see.

  • 11:42:03

    BORCHELTAnd a lot of people are blaming genetically modified organisms, as though that were the problem. Genetically modified organisms, like Roundup Ready soybeans make it much easier to practice intensive agriculture. It's not a problem in itself -- or least hasn't been identified definitely as a problem by itself -- but any time you can do much, much more intensive agriculture it's going to be very bad for the Monarchs.

  • 11:42:25

    REHMI see. Karen Oberhauser?

  • 11:42:31

    OBERHAUSERWell, just back to Lenny's question, what he saw in his garden is something that many, many people saw. I know a lot people in Michigan and Wisconsin and Minnesota who did not see any Monarchs in their gardens. So we had one of our lowest years ever in the Monarch larva monitoring project, which is a Citizen Science project that I direct. At the University of Minnesota we have data coming from all those places and the numbers are very low.

  • 11:43:00

    OBERHAUSERSo we know that this year was an extremely low year in the upper Midwest. And, you know, we can just hope that the numbers will go back to what they used to be. Probably because of intensification of agriculture they might not be the numbers that we saw in the 1990s, but hopefully Lenny will be seeing some Monarchs in his garden. And certainly he's doing the right thing by having the milkweed plants and the nectar sources available.

  • 11:43:25

    REHMBut now, Karen, what about the dramatic weather systems we've seen throughout the country? Might those have affected the movement of the travel of the Monarchs?

  • 11:43:42

    OBERHAUSERRight. So any year what we're seeing is both a reflection of the immediate weather conditions during that year, something that weather varies naturally, it also reflects long-term transient weather so we know that there's warming weather, there are more severe storms coming that are -- more severe weather will affect them. So we see actual trends in climate. But we're also seeing the impact of loss of habitat. So all of those things add up to affect the number of Monarchs that people like Lenny are seeing in our backyards.

  • 11:44:19

    REHMAll right. Let's try Susan, who's in Washington. She's online, too. Good morning, Susan. You're on the air.

  • 11:44:30

    SUSANHi. Thank you, Diane. And thank you so much for this program. I just wanted to say we're raising Monarchs with my daughter's first grade class and we were very alarmed locally here to see the populations really drop off. But I had a question related to the habitat issue that you just raised. And we also drove across country with our family this summer, to Yellowstone. And we crossed through South Dakota and Wisconsin and Minnesota, and we just noticed these vast oceans of corn.

  • 11:44:59

    SUSANAnd I was wondering about the possible relationship between the Farm Bill and specifically the Farm Bill conservation programs, which have traditionally provided billions of dollars for conservation and protection of millions and millions of habitat. Because of the sequester and the budget and big cuts, a lot of those funds have been lost. And I'm wondering if people are making the connection between the Farm Bill and the conservation programs and the loss of Monarchs, and if we can, you know, maybe alert our members of Congress that there is a connection between what they're doing here in D.C. and these beautiful butterflies.

  • 11:45:38

    REHMAll right. Rick, any comment?

  • 11:45:41

    BORCHELTSo, in general, and while I don't know the Farm Bill well enough or would comment on the Farm Bill well enough, in general the systems and the incentives for doing agriculture bigger, doing agriculture in monoculture, what you're seeing across the belt -- there's a reason why we call it the corn belt, increasingly becoming the soybean belt, too. Those are all problems and there are a lot of incentives for farmers to do that. There are fewer and fewer incentives for farmers to do diversified agriculture.

  • 11:46:12

    BORCHELTAnd there are fewer and fewer incentives for local homeowners to do anything other than green lawns. If there's one thing that all of us could do is get rid of our green lawns. And that's not just good for Monarchs, it's good for all butterflies.

  • 11:46:24

    REHMKaren, any other thoughts?

  • 11:46:26

    OBERHAUSERYes. The Farm Bill is very important. It has the potential to be a very important conservation tool in this country. And I'd really like to applaud all of the Congress people who are working to make it do that. One very important part of the Farm Bill is the Conservation Reserve Program, or as we in the Midwest always talk about the CRP program. And that supports farmers who are pulling land out of production and conserving that land instead of planting it. So that's an extremely important component of the Farm Bill that we all need to support.

  • 11:47:03

    OBERHAUSERAnd what we need to do is make sure that CRP land contains milkweed and nectar plants that will support Monarchs and all of the other insects that are important to us. So the Farm Bill is a really important conservation tool. And it's something that we should all learn about and try to support because it has the potential to do a lot of good things.

  • 11:47:25

    REHMAll right. Let's go now to Dennis, in Jacksonville, Fla. He's on line 5 here. Good morning to you, Dennis.

  • 11:47:37

    DENNISGood morning. This is kind of an off-the-wall thing. I heard several years ago that the migration of the Monarch from Mexico to Canada and back involves multiple generations of Monarchs. And I was just curious, is that really true? And if so, you know, how do they do it? And if not, how did that story get started?

  • 11:47:59

    REHMRick, you talked about that earlier.

  • 11:48:03

    BORCHELTIt is true the butterflies on their northward migration can have several generations going north. But the southward migration is one generation. So the butterflies that fly all the way from where ever their most northern spot is -- and it may be Canada, it may be the Northeast, it may actually be somewhere in the Midwest -- when they fly south to Mexico they fly in one single flight. Or at least they fly in one single generation. They make many stops along the way, but they -- and again, it's not so much that they fly, they float. They follow prevailing winds and they float most of the way to Mexico.

  • 11:48:38


  • 11:48:38

    DEWITTFor example, the Monarch that Diana is going to tag in just a little while, right out on Connecticut Avenue -- we're going to put a tag on it. And when we throw it up in the air it's going to head south.

  • 11:48:52

    REHMAfter I kiss it.

  • 11:48:53

    DEWITTThat's right. That's right.

  • 11:48:54


  • 11:48:55

    DEWITTAnd we will have proof of that. It's going to fly south. This Monarch was -- I caught it in my yard. It could have come from Canada. It could have already flown 1,000 miles. It's going to go down to Mexico and it's going to stay there until the days start getting longer, probably February, probably more like March. And it is only going to fly back up to Texas. And that's where drought -- that's what we're talking about, climate change can affect the milkweeds. It's not sexually mature right now.

  • 11:49:28

    DEWITTDown in Mexico, around March, it will become sexually mature as it's coming back up. And it will mate in Texas. It will lay eggs. Those eggs are going to hatch into caterpillars. Caterpillars are going to, you know, become the butterfly. That butterfly's only going to live about two or three weeks. Its young are going to continue to fly north to leap frog all the way up. Our area, we have about four generations, May, June, July, August, September. The Monarchs only live two weeks. It's just this last generation that lives for the whole year.

  • 11:50:04

    REHMAll right. And now to Tampa, Fla. Cleopis, you're on the air.

  • 11:50:11

    CLEOPISThanks for taking my call.

  • 11:50:12


  • 11:50:14

    CLEOPISAnd a wonderful show.

  • 11:50:15

    REHMThank you.

  • 11:50:16

    CLEOPISA question and a comment. In fact, comment first. In 1960 area, '65, '66, there was a report of a break in the ozone level that would be increasing every time or each time a plane breaks the sound barrier. Now, the ozone layer, I understood, is to protect the ultraviolet rays coming from the sun. And I think it passes through the Van Allen radiation belt. Now, the question is, is it possible that that non-filtering of ultraviolet light may have an effect on plant life, frogs, bees and skin cancer?

  • 11:51:07

    REHMAll right. Let's see what Karen has to say about that.

  • 11:51:13

    OBERHAUSERWell, we haven't looked at the impact of increased ozone levels on -- or the break in the ozone layer in the atmosphere on Monarchs or many other insects. But we do know that it can affect milkweed. So my guess is that would be an indirect effect because it's harmful to milkweed, but not directly to the Monarch.

  • 11:51:34

    REHMThis is so fascinating. I mean this creature on the one hand seems so delicate, so fragile, and yet, has the strength to fly these thousands of miles, yet we do know it's affected by everything that's going on in the atmosphere, everything that's going on in the environment, and everything that we as humans are doing. So it really makes you more conscious not only of the butterflies, the birds, as well. Rick?

  • 11:52:18

    BORCHELTAbsolutely. And there's a really interesting bird, Monarch butterfly interaction we haven't even talked about yet. And that's why I hope you'll kiss the butterfly very lightly because it tastes very, very bitter. And the reason it tastes very, very bitter, is that along with many other butterflies, it eats a very poisonous plant. Milkweeds are very, very poisonous.

  • 11:52:35

    REHMRight. I had heard that.

  • 11:52:35

    BORCHELTAnd they are able to take those poisons, sequester them in their bodies so that when a bird eats them or tries to eat them, they get this nastiest taste. It makes them vomit. If they aren't able to vomit, many times they will die if they're not able to throw up.

  • 11:52:48

    REHMThe bird will die?

  • 11:52:49

    BORCHELTThe bird will die.

  • 11:52:50

    REHMOh, my gosh.

  • 11:52:50

    BORCHELTThose are very toxic butterflies and that's why they're so bright orange and black. It's a warning.

  • 11:52:54

    REHMIs the Monarch the only one that's toxic or are all butterflies doing that?

  • 11:53:00

    BORCHELTNot all butterflies, but many butterflies seek out toxic plants to help protect them from predators.

  • 11:53:04

    REHMHow fascinating. And you're listening to "The Diane Rehm Show." Let's go now to Micheline, in Annapolis, Md. Hello, you're on the air.

  • 11:53:21

    MICHELINEHi. Thank you for taking my call.

  • 11:53:23


  • 11:53:24

    MICHELINEI just finished reading Barbara Kingsolver's novel, "Flight Behavior."

  • 11:53:29


  • 11:53:29

    MICHELINEJust really like last week. And I feel fairly certain that Dr. Oberhauser must have had some influence, if not actual contact, with Dr. Kingsolver, to...

  • 11:53:41

    REHMWell, you know, that's a fascinating question. Barbara Kingsolver was on this program November 8th of 2012. You can listen to that conversation online, if you like, about her novel "Flight Behavior." Karen Oberhauser, did you have any conversations with Barbara about that book?

  • 11:54:08

    OBERHAUSERNo. I didn't talk with her while she was writing the book. She worked with Lincoln Brower, who's another Monarch biologist. She did use a lot of my research and I’m acknowledged in the book, but I didn't talk with her. I think that it is really interesting, though, to think about that book because I think it illustrates what we call in behavioral ecology, the plasticity of Monarchs. The question earlier that Matt asked about will climate change make Monarchs go extinct, I think the answer to that is no. And I think the reason for that is they will probably change their behavior…

  • 11:54:46

    REHMThey will adapt somehow.

  • 11:54:49

    OBERHAUSERYeah, well, they'll change their behavior. And Barbara Kingsolver has an interesting theory for one of the things they might do differently. I think they probably wouldn't end up over-wintering in mass in Appalachia, but you know anything is possible.

  • 11:55:07

    BORCHELTI agree with that completely. These are incredibly robust animals. And incredibly resilient animals.

  • 11:55:12

    REHMYou called it an animal.

  • 11:55:14

    BORCHELTIt is an animal.

  • 11:55:14

    REHMIt's an insect.

  • 11:55:15

    BORCHELTButterflies are -- insects are animals.

  • 11:55:17

    DEWITTInsects are animals.

  • 11:55:18

    BORCHELTInvertebrate animals, as Tamie likes to call them.

  • 11:55:19

    REHMOkay. All right.

  • 11:55:21

    BORCHELTBut they're incredibly resilient. And they can stand a lot of stresses in their environment. One of the problems we're having is there are multiple stresses now, many of them human induced. And the issue with being able to adapt well enough to be able to survive some of these stresses, is do they have enough time. And we tend to be throwing things at them very, very quickly, faster than evolution and adaptation normally can handle. So that's one of the concerns we have, even though an individual female Monarch can lay up to 1,000 eggs. I mean, she may lay 1,000 eggs…

  • 11:55:55

    REHMAnd how many survive?

  • 11:55:58

    BORCHELTVery, very, very few.

  • 11:55:59


  • 11:55:59

    BORCHELTVery few.

  • 11:56:00

    REHMOut of 1,000, give me an estimate.

  • 11:56:04

    BORCHELTYou would be surprised. I think Karen may actually have better data on this, but I would be surprised if five or ten survive out of that, even if that many.

  • 11:56:10


  • 11:56:12

    OBERHAUSERRecent estimates suggested that it's about 1 to 2 percent. And they probably don't lay 1,000 eggs. That's the maximum we've ever seen in captivity. I think it's more like 500 probably in the wild, although it's really difficult to measure that. So, yeah, the survival is very low.

  • 11:56:32


  • 11:56:32

    DEWITTAnd when you talk about survival, it's not that they all just die. They become food. They become part of the food web. So we talked about birds. Lincoln Brower's barfing blue jays, when they eat the Monarch and throw up, but there are insects or arachnids, like spiders, that are a very big predator of the Monarchs. They can actually eat the Monarch without having that cardiac side effect affect their heart the way birds do or mammals.

  • 11:57:01

    REHMWhat a fascinating creature this is. I'll be happy to go outdoors and tag it. Tamie DeWitt, Rick Borshelt, Karen Oberhauser. And once again, Karen, congratulations to you. Thanks to all of you for being here and talking about this beautiful creature, the Monarch butterfly. Thanks for listening all. I'm Diane Rehm.

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