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precarious time for monarchs and their migration

Dr. Karen Oberhauser, University of Minnesota Monarch Lab (photo courtesy Dr. Oberhauser)‘WHERE ARE THE MONARCH BUTTERFLIES this year?’ one of many 2013 emails on the topic asked me. Headlines about monarch decline seem to confirm gardeners’ observations: Populations of the once-familiar orange-and-black creatures are not what they were.  What’s going on, and how bad is it?  Is there anything we can do? I invited conservation biologist Dr. Karen Oberhauser, a University of Minnesota professor and leading force in its Monarch Lab, who has studied Danaus plexippus for almost 30 years, to my latest radio show to explain.

prefer the podcast?

IN OUR CHAT on my public-radio show and podcast, Dr. Karen Oberhauser of the University of Minnesota Monarch Lab answered many of my monarch questions. Listen anywhere, anytime: Locally, in my Hudson Valley (NY)-Berkshires (MA)-Litchfield Hills (CT) region, “A Way to Garden” airs on Robin Hood Radio’s three stations on Monday at 8:30 AM Eastern, with a rerun at 8:30 Saturdays. It is available free on iTunes, the Stitcher app, or streaming from RobinHoodRadio.com or via its RSS feed. The September 16, 2013 show can be streamed here now. Robin Hood is the smallest NPR station in the nation; our garden show marked the start of its fourth year in March, and is syndicated via PRX.

the 2013 numbers: how bad a decline?

Monarch on confelower; photo courtesy Monarch Lab.INDEED, SAYS OBERHAUSER (above) the 2013 data aren’t rosy. Counts are made at various life stages, including during spring and fall migration, and the areas occupied in overwintering times (in Mexico and California) are also measured, yielding what may be the most accurate numbers on total population.

“Last year [2012] at the overwintering sites, the area occupied was at only 60 percent of its previous low,” she says. “It had been declining, but that was astonishingly low.”

The migration-monitoring program Journey North also reported lower stats in 2013’s cold spring. And though the numbers were only preliminary when we spoke that fall, University of Minnesota’s Monarch Larva Monitoring Program seems to indicate that “we’re at about 20 to 30 percent of our average,” Oberhauser says, acknowledging that these drastically lower numbers might be a “new normal.” But she’s not sounding defeated, by any means.

A big positive: A lot of people are interested in monarchs. “Though it will be difficult to make up for all the habitat we’ve lost, we can make that ‘new normal’ as good as we can.”  (Ways to help are father down this page.)

what going wrong for monarchs?

MONARCH DECLINE is a problem with multiple causes, says Oberhauser. The three big factors: habitat loss, chemicals and changing weather with many extreme events.

  • Habitat loss has resulted from land shifted to agriculture, suburban sprawl or ex-urbanization—“wherever there is Kentucky bluegrass” instead of former habitat, Oberhauser says—and other development, or even activities like mowing, such as along so many miles of highways.
  • The widespread use of chemicals in agriculture and otherwise has hit monarchs two ways: Herbicides can kill off milkweeds that once sustained larvae, leading to the loss of their host plant, and insecticides (used to kill adult mosquitoes, for instance) can kill any insects (though mosquito larvicides don’t affect monarchs).
  • Increasingly frequent aberrations in climate can be costly, too, whether extremes of cold, drought or other forces–especially when they occur during migration.

an endangered phenomenon: monarch migration

EVEN MORE than the butterfly itself, it’s the astonishing phenomenon of monarch migration that seems to be endangered.

“The migration really depends on a long chain of habitat, and if any links in that chain are broken, it’s very possible that we would lose the phenomenon,” says Oberhauser, who again offers a bright-ish counterpoint:

“But monarchs themselves are a very resilient or ‘plastic’ species—meaning they have behavioral plasticity—they can basically change their behavior to be appropriate for the environment they find themselves in.”

Though monarchs are a New World species, they have found their way to Hawaii, Australia, New Zealand, Southern Spain, Portugal–very different places from where they evolved. “And when they get to a new place they just kind of do the right thing,” says Oberhauser. In Hawaii, for instance, they don’t need to migrate. In Australia, they need to migrate out of dry areas part of the year. And so on. Adaptable.

how does monarch migration work?

IN FALL, MONARCHS in the northern parts of the country and into Canada are seeking nectar sources to fuel up for their flights south.  They’ll fly all the way all the way to somewhere along the California coast (if they start out West), or down into Mexico from the East, and will stay there throughout the winter.

“What they need there is a safe place that will shelter them, but can’t be too hot—which would burn up all their fat reserves,” says Oberhauser, “and it can’t be too cold, either.”

Around the middle of March, the overwintering monarchs start to leave Mexico (or California) for the journey north.  Few make it all the way back; they lay eggs along the way, in northern Mexico and the Southern U.S., and those subsequent generations eventually continue moving up the continent.  More generations are born up north in summertime, the last of which start the move southward again. A full chart on the life cycle is on this page at the Monarch Lab website, with a map and explanation also at the Monarch Joint Venture site.

how can we help monarchs?

Milkweed by David Dube, courtesy Monarch Lab website.The MOST IMPORTANT ways individuals, including gardeners, can help monarch butterflies:

1. Try to make as much habitat available as possible. Unmow some of that monoculture of lawn; plant milkweed and nectar sources as part of the wilder area.  (Oberhauser’s average-sized yard has 117 milkweed plants in it, for instance. It can add up, if we all help. “There’s a lot of Kentucky bluegrass out there,” she points out.)

Monarch larvae, or caterpillars, mostly eat milkweed (Asclepias), though the larvae can feed on a few other genera in what used to be in the milkweed family—but no longer are classified that way. One of the plants is Cynanchum laeve, or sand vine. Adult butterflies use various flowering plants as nectar sources, including milkweeds; eupatoriums such as boneset and Joe-Pye weed; goldenrods; asters; blazing star or Liatris; ironweed or Vernonia; many daisy-like plants and more.

  • Which milkweed? To identify which milkweed (Asclepias) species are best suited to your habitat, get the pdf chart here.
  • Using native plants: One of the Monarch Joint Venture members, called Wild Ones, has a “Wild for Monarchs” campaign, promoting native plants in people’s yards and gardens. Get more info.
  • More downloads: An entire selection of free downloadable publications, including that one, can be had at this link.

2. Volunteer to be a citizen scientist in behalf of monarchs–even if you only have a few milkweeds, says Oberhauser. The more data the better.  Here’s a list (in a pdf) of all the organizations around the country. The Monarch Larva Monitoring Project, Journey North, and Project Monarch Health are possibilities. Or tag monarchs to help study their fall migration, either through Monarch Watch in eastern North America, or the Southwest Monarch Study in the west.

3. Donate to conservation organizations like the Monarch Butterfly Fund or the Monarch Joint Venture. These organizations work on monarch conservation in Mexico and the US, respectively.

(All photos courtesy of the Monarch Lab website.)

  1. Doreen says:

    I live in the town of Poughkeepsie NY and have not seen one monarch this year. Several weeks ago, the local cable news reported d there were fewer monarch butterflies this year due to the fact that pesticide use on fields in the Midwest killed milkweed plants needed by monarchs. I try to do my part, I do not use any pesticides in my yard which is a NWF Certified Wildlife Habitat. It is very sad to see them disappear.

  2. Barbara says:

    I live in Saratoga County (NY) and I, too, have not seen a single monarch this year. My yard is a certified wildlife habitat and is usually a flutter with all sorts of butterflies. Not so much this year, despite offering plenty of milkweed and other butterfly-friendly native plants. Very worrying.

  3. Liz Hathway says:

    I live close to Presqu’ile on the north shore of Lake Ontario. This is one of the main gathering spots for the Monarchs as they prepare to migrate south. Each year I have been delighted and marveled at the phenomena of having my trees suddenly turn orange and for about a week in mid-Sept., when I stepped out I had Monarchs flying into me and landing on me in swarms! The first time I observed this, I looked out and panicked, thinking that all our trees had suddenly died overnight! That was 18 years ago. Last year the owner of the vacant fields across the road was told that he had to plant those fields or have a large increase in taxes, as the land would no longer be considered “agricultural”. So it was cultivated and planted with corn (probably GMO). They never even bothered to harvest it! This year it has begun to revert to more natural growth. I don’t know whether there is a connection but this year when the air should have been filled with Monarchs, I have been lucky to see 2 -3 / day. Makes me very sad. Most of my neighbours maintain a wide lawn-like swathe across the road adjacent to the vacant field, but I refuse to. I am keeping a close watch on the few milkweeds that have managed to persist across my road with the intention of harvesting the seeds and spreading them in the “wilder” areas of my property and sharing them with my sons who also have wilderness areas at their homes. I may even do some guerilla gardening while on my morning walks. For those who are interested in the fate of the Monarchs, if you haven’t already read it, I recommend Barbara Kingsolver’s book “Flight Behavior”.

    1. margaret says:

      Hi, Liz. What a dramatic story that illustrates the plight so well, unfortunately. Thanks for reminding us of Kingsolver’s book, too.

      Thanks to you, too, Jules — I should do a giveaway “event” on the website of her book, which I do have! Nice to see you both.

  4. Jules says:

    I too have only seen a handful all over my mid-west travels this summer – not at all like in the past. When we lived in Nebraska, we would see tons heading south in the fall over the playground where I worked. The children were always in awe of this phenomenon. Just read Barbara Kingsolver’s Flight Behavior this summer – her fictional story is indeed becoming all too true.

  5. Azucena Gee says:

    I am in the Southern California area. I am trying to grow milkweed anywhere it can land. It has paid of this year. I have three monarch butterflies that fly throughout the day. Last year i may have had only one.

  6. Diane Genco says:

    I have a Monarch Way Station certified garden in Central NJ
    Last year at this time I had harvested Monarch eggs,and reared caterpillars, released and tagged 200+
    This season , I have one released 1 and have
    and 10 caterpillars .
    This from only 2 Monarchs
    I am very anxious about this and saddened.

  7. heidih says:

    Great informative blog post and links. I am in the Los Angeles area and have lots of them in my garden as does our local botanic garden. Even though the asclepias are looking kind of puny this time of year, and those yellow aphids are prolific I am still seeing big fat caterpillars. At our fall plant sale last weekend the asclepias and other butterfly friendly and hummer and bee friendly plants were in high demand – people do care but they need good info like you have provided.

  8. Cynthia says:

    Once we learned more about the Monarchs and other birds that nest during summer a few years ago, we changed the brush hog/mowing schedule of our fields from early summer to the late fall. As a result, we’ve got fields of milkweed, golden rod and others which not only looks beautiful, but we’ve also had an increase in Monarchs as well!

  9. Lisa says:

    It is sad to hear that they need an unbroken chain of habitat because even though as gardeners we can do our part, we can’t control what others do. I have loads of milkweed in my garden in the Minneapolis suburbs and I do not use pesticides, but I only saw a few monarchs this year–none in my back yard. I am hoping part of it had to do with the exceptionally late Spring and we will see more next year. I have not seen many swallowtails this year either and I remember years when we had so many they would hang off the flowers.

  10. Eileen J says:

    In my town, thanks in part to the activities of the university here, the city and some schools and businesses plant “monarch way stations” – patches of garden that feature milkweed and other plants that support monarchs. Milkweed is a pretty plant with a pretty flower, and just now the seedpods are bursting open and the cottony seeds are taking flight. If you can find a plant you can probably get some seeds!

  11. Lisa-St. Marys ON says:

    I understand the farmers not wanting the milkweed in with their crops – fair enough. But they all have become too busy mowing along the roads! And once one farmer does it, all of them have to have it “tidy”. The loss of the roadside ditches is surely hundreds or thousands of acres of habitat lost. Unfortunately it would be a very hard sell to tell the farmers that it is wrong to clean up their ditches. It would need to start at the schools with their children. I believe that is the only way to get the message across to them.

  12. Onoosh says:

    I’ve read a lot recently about plants from big commercial nurseries being unfriendly to bees, since they appear to be grown using systemic insecticides before being shipped out to big box retailers. If this is true, I assume it affects monarchs, too. What sources are out there for bee and butterfly-safe plants? I’m in the northwestern corner of South Carolina, and even our smaller, local nurseries order their plants from the same sources as the big guys.

  13. Hannelore says:

    About five years ago I planted some Mexican Sunflower seeds. Not only did everybody who saw the plants want to know what these beautiful flowers were, but the Monarch butterflies were all over them. I now plant the seeds every year and share the seedlings with my friends.
    By the way, the Organic Gardening Newsletter just sent an article “A Honey Bee Menu for Pollen and Nectar” with a list of plants.

  14. Kathy Sturr of the Violet Fern says:

    Last year I had many butterflies and this year practically zilch except for the Cabbage Whites and four, yes only four, Monarchs. Very discouraging. I have even left the volunteer common Milkweed to grow in the cracks of my sidewalk entrance much to the wonderment of my neighbors!

  15. carol13 says:

    I live in central Maryland. My yard is also NWF & Bay Friendly certified. I’ve had tons of Cabbage White & Sulphur butterflies, & a veritable swarm of Swallowtails (esp. Black Swallowtails), but – only 3 Monarchs. Scary.

  16. Lorie says:

    This year, in eastern NE, finally a few Monarchs were back…1/2 dozen.. which is a good number. They mostly feasted on the Joe Pye and aesclepius, but there was dill, etc. too. There is a town, a couple of miles west of here, named Papillion, because of the huge numbers of Monarchs that used to migrate through. You could actually drive down the street and see groups of them flying across the road in migration.

  17. Nadia@Loveliveandgarden says:

    I planted milkweed this year and have been giving away the seeds in an effort to help the monarch butterfly. I live in California and I planted it on a neglected hillside I have. I’ve had a sharp increase in monarchs visiting my yard as a result of it. I also have a Himalayan mulberry tree that they visit quite frequently. This is such an important issue to talk about. Thanks for the post.

  18. Linda Porter says:

    We have a monarch waystation (via Monarch Watch) in Central Kentucky. In August the egg laying began on almost every milkweed we have in our way station – swamp, common, tuberosa and, alas, tropical given to us by a friend. We had a total of 42 caterpillars and hand raised half of them. We have released 6 butterflies thus far with several more in chrysalis and spotted four that grew to maturity in our yard. We live near a wooded area and a lake. Completely organic. There may be hope.

    1. margaret says:

      Love this story of personal involvement, Linda; inspirational! I am busily ordering more plants to tuck into my unmown areas this fall…and maybe next year I will join you in the official ranks!

  19. Nancy B says:

    thanks for this post. after 3 years of planting habitat for butterflies–yesterday I happened to be out in the pm and caught a single monarch dancing & drank @ the garden for a full 20 mins–I was mesmerized. YOU are finally here I thought –where’ve you been? where’re YOU going!? and off to south it flew…and I wondered so they speak spanish ?

  20. Nancy B says:

    After 3 years of planting habitat for butterflies in central CT–yesterday I happened to be out in the pm and caught a single monarch dancing & drank @ the garden for a full 20 mins–I was mesmerized. YOU are finally here I thought –where’ve you been? where’re YOU going!? and off to south it flew…and I wondered do they speak spanish ?

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