Monarch Fallout and A Predator Story

Monarch Fallout

It happened again in 2020. The convergence of the peak of the September monarch southerly migration over Southcentral Kansas was met by a strong south wind, causing a “fallout” of monarchs at the Dyck Arboretum. Rather than waste energy fighting the headwind, monarchs find a place of refuge to rest and sip nectar. I would estimate that I’ve seen this phenomenon happen five times in the Arb since 2005 and this year’s was the most memorable for a few different reasons including big numbers, fallout location, and a predator story.

Monarchs in the Hedge Row at Dyck Arboretum, 9/20/2020 – Photo by Gerry Epp

Big Numbers

The monarch numbers I observed on Monday, 9/21/2020 seemed to me to be more stunning than I can ever remember. I estimated conservatively in a report to Journey North, there were at least 500 monarchs resting in the Arboretum that day. But after giving it more consideration and talking to a local monarch tagger, Karen Fulk, I wonder if that number was more accurately in the thousands.

Karen’s many years of efforts to tag monarchs in Hesston has her keenly in touch with monarch phenology and migration patterns. She reports that the peak of migration through south central Kansas is usually between 9/22 and 9/27. This year, however, she started seeing an uptick in numbers when a cold front and north wind jump-started the southerly monarch migration a bit earlier.

Karen usually tags 300 annually during the fall migration. This year, Chip Taylor at Monarch Watch, knowing that migration numbers were higher this year, suggested that taggers order extra tags. Karen increased her number to 500 tags and was able to apply most of those when the fallout began Friday 9/18/2020 through Sunday 9/20/2020. Arboretum member, Gerry Epp, further documented this event by posting photos of the fallout on his Facebook page, 9/20/2020.

Monarchs on Seven Son Flower at Dyck Arboretum, 9/20/2020 – Photo by Gerry Epp

Fallout Location

With some repetition now in seeing these fallouts occur in the same place, I want to give some thought to why they congregate where they do at Dyck Arboretum. Karen usually tags at three places in Hesston based on the ability to catch and tag the maximum number in one place, and Dyck Arboretum is where she does the majority of her work. She estimated that 95% of her tagging this year happened at the Arboretum, based on seeing the greatest number of butterflies here.

I would hypothesize that they repeatedly congregate in the small 1/8th-acre area at the Arboretum amphitheater/pinetum for three reasons. One, they are seeking protection from the elements of wind and heat. This is about energy conservation. By escaping the wind and congregating in large groups on the north side of the dense hedge row of Osage orange trees, they are finding a microclimate that is cooler, more humid, and less turbulent than they would find on the south side.

Monarchs on Seven Son Flower at Dyck Arboretum, 9/20/2020 – Photo by Gerry Epp

Two, this location is next to a number of nectar sources. Why not rest where you can eat/drink too? Nearby native plant beds and a reconstructed prairie had a timely profusion of flowering from many species of the genera Helianthus (sunflower), Solidago (goldenrod), Symphotrichium (aster), Liatris (gayfeather), Eryngium (eryngo), and Heptacodium (seven son flower).

Three, a number of white pines in this location may resemble the trees of the Oyamel fir forests in Mexico. I don’t have any proof of this theory, but it seems plausible to me.

Predator Story

The newest wrinkle of this monarch fallout experience was the side story of five immature Mississippi kites. They were probably migrating with the monarchs and decided also to not fight the strong south wind. For a day and a half that I observed, this hungry bunch of pentomic predators took advantage of an abundant food supply. They hung out in the top of one of the white pines and took turns swooping through the monarch clouds to easily catch a snack.

Mississippi Kite Eating A Monarch at Dyck Arboretum, 9/22/2020 – Photo by Janelle Flory Schrock

Sometimes they missed catching their target, but usually, these agile insect catchers snagged their prey. Typically they would return to their perch to eat their catch, but sometimes they would eat in flight or “on the wing” as I hear experienced birders say. At one point, I counted approximately 120 monarch wings that had fluttered down to form what I’ll call a monarch confetti debris field. At four wings per monarch, that represented the carnage of about 30 monarchs. However, a number of wings had already been collected by onlookers, so it is not unreasonable to think that the number of monarchs preyed upon were double or triple what I saw.

Monarch Wings at Dyck Arboretum, 9/20/2020 – Photo by Brad Guhr

Monarch Toxicity

This predator behavior was a surprising observation. Monarch larvae eat milkweed and sequester in the mature butterfly wings and exoskeleton the milkweed toxins called cardiac glycosides. These heart poisons can seriously affect vertebrate predators, including birds, and often cause them to vomit and subsequently avoid eating them further. However, these young kites not only ate monarchs all day Monday, but they continued their feeding frenzy the next morning. Either their stomachs weren’t too adversely soured, or the calories needed to continue this migratory journey were simply too important.

A Google literature review turned up no articles mentioning this habit of Mississippi kites eating monarchs. However, a follow-up conversation with University of Kansas biology instructor, Brad Williamson, helped me understand that this observation is not so irrational. He explained that the monarch population is not 100% toxic.

“The individual toxicity depends a lot on the particular milkweed species that hosted the larval stage. Asclepias syriaca (common milkweed) and Cynanchum laeve (honeyvine milkweed) are not nearly as toxic as A. verticillata (whorled milkweed). There is an entire range of toxicity and it makes for some great mathematical modeling questions–just how much toxicity (percent toxic) in the population is necessary for protection for the entire population? How much metabolic costs are there for monarchs trying to process highly toxic host plants? Turns out that only 25-40% of the population being toxic confers protection for the remaining population.” (I will include below a bibliography on monarch toxicity that Brad Williamson provided if any of you are interested as I am in learning more about this topic.)

There were a lot of interesting biological and ecological issues at play here with these monarchs and kites. It was just one more interesting natural history story with subplots to be observed by those of us living in the Monarch Flyway. Until I’m able to one day witness the hundreds of millions of monarchs wintering in the the Oyamel forests of central Mexico, I am completely content having a front row seat to this fascinating migration phenomena right here in Kansas.

Monarch butterflies observed at the Monarch Butterfly Biosphere Reserve in Michoacán, Mexico. Video by Beatrix Amstutz, February 7, 2020.

Plant Milkweed

To assist the monarchs and their annual migration, plant milkweed host plants and other native nectar plants for adults. Check out our annual spring and fall Flora Kansas native plant sales.

Articles on Monarch Toxicity

  • Brower, L. P., and C. M. Moffitt. “Palatability Dynamics of Cardenolides in the Monarch Butterfly.” Nature 249, no. 5454 (1974): 280–283.
  • Brower, Lincoln P. “Avian Predation on the Monarch Butterfly and Its Implications for Mimicry Theory.” The American Naturalist 131 (1988): S4–S6.
  • Brower, Lincoln P., and Susan C. Glazier. “Localization of Heart Poisons in the Monarch Butterfly.” Science 188, no. 4183 (1975): 19–25.
  • Brower, Lincoln P., Peter B. McEvoy, Kenneth L. Williamson, and Maureen A. Flannery. “Variation in Cardiac Glycoside Content of Monarch Butterflies from Natural Populations in Eastern North America.” Science 177, no. 4047 (1972): 426–429.
  • Fink, Linda S., and Lincoln P. Brower. “Birds Can Overcome the Cardenolide Defence of Monarch Butterflies in Mexico.” Nature 291, no. 5810 (1981): 67–70.Malcolm, S. B., and L. P. Brower. “Evolutionary and Ecological Implications of Cardenolide Sequestration in the Monarch Butterfly.” Experientia 45, no. 3 (1989): 284–295.
  • Malcolm, Stephen B. “Milkweeds, Monarch Butterflies and the Ecological Significance of Cardenolides.” Chemoecology 5, no. 3–4 (1994): 101–117.
  • Malcolm, Stephen B., Barbara J. Cockrell, and Lincoln P. Brower. “Cardenolide Fingerprint of Monarch Butterflies Reared on Common Milkweed, Asclepias Syriaca L.” Journal of Chemical Ecology 15, no. 3 (1989): 819–853.
  • Nelson, C. J., J. N. Seiber, and L. P. Brower. “Seasonal and Intraplant Variation of Cardenolide Content in the California Milkweed, Asclepias Eriocarpa, and Implications for Plant Defense.” Journal of Chemical Ecology 7, no. 6 (1981): 981–1010.
  • Roeske, C. N., J. N. Seiber, L. P. Brower, and C. M. Moffitt. “Milkweed Cardenolides and Their Comparative Processing by Monarch Butterflies (Danaus Plexippus L.).” In Biochemical Interaction between Plants and Insects, 93–167. Springer, 1976.
  • Zalucki, Myron P., Lincoln P. Brower, and Alfonso Alonso-M. “Detrimental Effects of Latex and Cardiac Glycosides on Survival and Growth of First-Instar Monarch Butterfly Larvae Danaus Plexippus Feeding on the Sandhill Milkweed Asclepias Humistrata.” Ecological Entomology 26, no. 2 (2001): 212–224.

Are you ready for the Monarchs?

Spring is coming.  Nature is not locked down, but continues to come to life.  We notice the buds expanding and the crocus blooming.  Leaves emerging from the depths and plants all around us waking from their winter slumber.  As spring unfolds around us, something extraordinary is about come our way again.  The Monarchs are coming. 

Monarch ovipositing on common milkweed. Photo by Brad Guhr
A monarch caterpillar munching on a milkweed. Photo by Brad Guhr

Providing for pollinators

The monarch’s annual spring migration north from Mexico has begun.  You can track their progress through Monarch Watch and Journey North.  Each year we take note of when this incredible journey passes through our area.  It is amazing to think that these delicate creatures can make this trek north and south every year.        

Statistics show that the monarch butterfly population in North America has declined by over 90% in just the last 20 years.  This is disheartening.  One of the biggest factors in monarch decline is the increasing scarcity of its only caterpillar host plant: milkweeds. Monarchs can’t successfully reproduce, or migrate without milkweeds, resulting in the species decline.

Monarchs also need other blooming native wildflowers, trees, and shrubs that provide nectar for the adult butterflies to feed upon.  This habitat, critical to the survival of the monarchs, continues to disappear at an alarming rate.  This natural habitat decline is taking a steep toll on wildlife of all types.

Monarch on New England Aster in the fall. Photo by Janelle Flory Schrock

Plant more than milkweed

Many of us are planting milkweeds and native nectar plants in our gardens to help monarchs survive.  Here is a list of plants from our Native Plant Guide that monarchs prefer:

Perennials

  • Aster ‘October Skies’
  • Aster ‘Raydon’s Favorite’
  • New England Aster (Aster novae-angliae sp.)
  • Blackeyed Susan (Rudbeckia)
  • Coneflowers (Echinacea sp.)
  • Coreopsis
  • Blazing Star (Liatris sp.)
  • Beebalm (Monarda sp.)
  • Milkweeds (Asclepias sp.)
  • Yarrow (Achillea sp.)
  • Eryngium yuccifolium
  • Goldenrod (Solidago sp.)
  • Zizia aurea
  • Vernonia ‘Iron Butterfly’
  • Veronicastrum virginicum ‘Lavender Towers’
  • Prairie clover (Dalea sp.)
  • Joe Pye Weed (Eupatorium sp.)

Shrubs

  • Chokeberry (Aronia sp.)
  • Leadplant (Amorpha sp.)
  • ServiceBerry (Amelanchier sp.)
  • Buttonbush (Cephalanthus sp.)
  • American plum (Prunus sp.)
  • Elderberry (Sambucus sp.)
  • Viburnum (Viburnum sp.)
Buttonbush bloom

Trees

  • Buckeye (Aesculus sp.)
  • Redbud (Cercis sp.)
  • Persimmon (Diospyros sp.)
  • Linden (Tilia sp.)

Stretch the season

A greater variety of plants will attract a greater variety of wildlife, including monarchs.  Try to plant several species of wildflowers with varying bloom times, providing nectar sources that stretch through the season. Different pollinator populations peak at various times through the warm months, so provide for them by having a long blooming garden. Early spring and late fall flowers can help sustain migrating species in the difficult stages of their journey. Research has shown that a lack of late season nectar sources is as crucial to migration success as milkweed. Help these insects get the energy they need all through the year!

If you plant even a few milkweeds in your own garden, you can help reverse the fortune of these beautiful insects.  Support habitat and other food sources for monarch butterflies and other wildlife by planting native plants.  It is always beneficial to reduce mowing, and limit or eliminate the spraying of herbicides and pesticides.  You can be part of the ultimate solution, which is to provide the plants monarchs need for their life cycle.  Watch for these incredible butterflies.  They are coming. 

One final thought I came across the other day:

“To plant a garden is to believe in tomorrow.” – Audrey Hepburn

Butterfly Hunting 101

Fall is an excellent time of year to go searching for butterflies. The late season flowers like goldenrod, asters, and maximilian sunflowers are all important nectar sources, and are usually swarming with pollinators. If you want to get the most out of your butterfly watching expedition, consider these helpful hints.

Grey hairstreaks (Strymon melinus) are my favorite butterfly, even though they are very small and not overly showy. I caught a picture of this one as it fed on wild quinine flowers.

Look on the Sunny Side

Butterflies are most active on sunny, warm days, because they cannot regulate their own body temperature. This is why you don’t see them fluttering around in deep shade – their flight is dependent upon body temperature, which is dependent upon the sun. Daytime temperatures between 80-100 degrees fahrenheit are optimum. Anything colder and they will start to slow down or quit flying all together. To warm themselves back up to flying form, they ‘bask’ by spreading their wings and sitting very still on a rock or sidewalk to soak up heat from the sun. For a successful butterfly hunting mission, be sure to choose a warm day and look in areas of full sun.

Bordered patches are commonly found throughout the southwest US and Northern Mexico, but I have spotted quite a few in Kansas through early fall.

Keep an Eye on the Weather

Cold fronts and warm fronts can have a big impact on the kind of butterflies you will see. Earlier this week, a strong south wind stalled several hundred monarchs from continuing their journey to Mexico. Choosing not to waste precious energy and fight the wind, they hunkered down in protected areas of the Arboretum and waited it out. When monarchs gather together in groups and rest on tree branches, they are ‘roosting’. They do this at night as well, or to avoid flying in a storm. Additionally, strong winds can blow in butterflies that aren’t usually in our range or cause otherwise active butterflies to be still, giving you a good opportunity to view them in detail.

This video was taken last fall in our butterfly garden. Asters are a great pollinator attractant, as you can see by the monarchs, queens, painted ladies and bees all enjoying their lunch.

Get a Better View

A pair of good binoculars can greatly enhance your butterfly watching experience and allows you to see details that the naked eye might miss. Short range binoculars, meant for backyard birding perhaps, give you a much more detailed view of nearby butterflies without getting too close and startling them. This can be especially useful when you are butterfly watching with children. Often excitable and loud on these kinds of outings, children can be taught how to use binoculars to keep them at a distance and prevent them from scaring away all your winged friends!

This viceroy butterfly is a monarch look-a-like, but is smaller and has a horizontal line on its hindwings that help us tell them apart.

Dyck Arboretum is a great place to come for a butterfly watching experience, and we often have many species feeding at once in our butterfly garden area. But it’s easy to attract these beauties to your own home by planting native and adaptable plants that provide food and shelter. We still have a few plants for sale in and around our greenhouse. I’d would love to help you create a butterfly oasis of your own! Call the office today and ask about our remaining inventory and special sale items – coneflowers, a butterfly favorite, are 25% off through October 5th.






Three Reasons I Am Intrigued by the Monarch Migration

Last week (late September) the Monarchs began to congregate in the arboretum.  There are hundreds of them hanging from the branches in the hedgerow of our amphitheater.  They are pooling here until the next north wind can help push them south.

DyckArboretum.Monarchs.9.23.15

In the last few years, we have only seen a handful in the arboretum during their annual migration.  When I first started working here many years ago, they would cover the trees, turning them orange and black.  We have certainly seen the decline of the population since then, but I am hoping the Monarchs hanging from the trees today signal a turn-around of the decrease encountered since the 1990s.

It is a wonderful and exciting sight to see so many of them.  I could spend hours watching the Monarchs.  They are mesmerizing, thought-provoking and captivating all at the same time.  Here are three reason why they intrigue me so much.

1. They are delicate but strong.

How can something so beautiful and fragile make the nearly 2000 mile journey from Canada to central-Mexico?  Every autumn, millions of monarch butterflies survive this incredible journey.  From start to finish it takes them two months to make the trip.  These delicate monarch butterflies are a marvel of nature.   We admire their beauty and endurance.  If you really think about it, the migration is one the most amazing in the natural world.

 

2. They love milkweeds and find them in the landscape.

I have heard that Monarchs can smell milkweeds from over two miles away.  It may be from even further away if the milkweed population is large.  Wow, do they have good senses, but their survival depends on them finding milkweeds.

Monarchs use receptors on their antennae to “smell” the milkweeds in your landscape.  As they get closer to the plants, sight takes over to land on the actual plant.  They make the final assessment of the plants with receptors on their feet. So more milkweeds in your landscape will only increase the odds of attracting Monarchs to your garden.

IMG_4559

Baby Monarch Caterpillar

 

3. They use the winds to aid their migration.

As they have been resting and waiting at the arboretum this week, the Monarchs have been feasting on the wildflowers in bloom such as asters, goldenrods, and sunflowers.  I anticipate their departure as soon as the next north wind comes sweeping down the plains.

LateSummerFlowers-2008_ 048

They use the updrafts called “thermals” and prevailing winds to their advantage, much like migrating birds, to preserve energy.  Their flapping wings can propel them southward at speeds ranging between 10 to 25 miles an hour.  Monarchs can travel 50-100 miles per day to complete the two months journey.  There will be time to rest when they finally make it to the warm Central Mexican Oyamel fir forests in the Michoacan hills.

The annual Monarch migration is a magical event.  These winged wonders captivate my/our attention every year.  How can something so small go so far?  It is truly extraordinary how they flutter all the way south.  They are worth saving.  Join me in planting milkweeds and establishing the habitat sanctuaries they need.  We can all be part of the solution.