News Brief by Kip Hansen – 21 March 2022
The magical marvelous Monarch Butterfly is surging – they are ramping up – populations numbers are skyrocketing! That is to say, according to Monarch censuses, the numbers of migrating Monarchs overwintering in both the Western Migration and the Eastern Migration have vastly improved over last year.
Monarch butterflies (Danaus plexippus) and their annual North American migration represent one of the mysteries of the animal kingdom, with their so-far inexplicable ability to produce one generation each year capable of traveling up to 2,500 miles and then, even after such a long journey for such a small insect, overwintering, without any eating, until Spring, at which time they fly north again eating and mating along the way.
Monarchs feed on flower nectar, like other butterflies, but in order to breed, they require milkweed plants, on which they lay their eggs. Although milkweed is slightly poisonous, monarch caterpillars will only eat milkweed leaves. It is believed that changing agricultural practices to suppress weeds and the widespread mowing of highway verges has greatly reduced the available milkweed for monarchs and contributed to their declining numbers.
And this last winter?
The Western Migration (and see map above) showed a fabulous comeback. According to the Xerces Society, the western migration for the 2021-2022 season was a great success with upwards of 250,000 monarchs found overwintering known sites along the southern California coast from Monterey south to San Luis Obispo. Xerces says this is “an over 100-fold increase from the previous year’s total of less than 2,000 monarchs and the highest total since 2016.”
How can this be so? No one is really sure. For any closely watched annual natural phenomena to increase by 100 times in a single year is more than a little unusual.
However, it is not strange at all to those who are familiar with real-world population dynamics. It is possible that the Western Monarch population may be acting like an “island species” in which local abundance or scarcity of sources and intra-species competition control species population size. In these conditions, the mathematical formulas of population dynamics show definite chaotic features, including population crashes and booms (see the graphic of May Island Squirrel Population). The actuality of this type of chaotic behavior has been confirmed in the natural world many times.
Monarchs, however, are capable of living year-around in the southern parts of California and the northern parts of Mexico and are found quite commonly living and breeding at all times of the year. This means that not all the monarch west of the Rockies take part in the annual migration. Many just do what humans often do, they move to southern California for the winter and get on with their normal lives. For monarch, that means mating, laying eggs, dying, and the new generation hatches as caterpillars which eat milkweed and pupate to become new monarchs. Tagging efforts have shown that some few Western Monarchs may even migrate to the same sites in Central Mexico as the Eastern Monarchs.
Extinction fears for the Western Monarch are not about a real extinction of Monarch butterflies west of the Rocky Mountains, but rather the fear that the Western Monarch Migration will cease to exist: “…in 1983, the IUCN took the unprecedented step of creating a new category in the Invertebrate Red Data Book, in order to list the monarch migration as a Threatened Phenomenon. This is because the numbers of American migrants are falling sharply. Figures for 1997-2016 show a 74 percent decline in California’s overwintering monarchs.” And last year, the numbers for the western migration were vanishing small….almost nonexistent.
Possibly contributing to the increase has been quite a bit of citizen-group action in the West to plant milkweed both in home gardens and on public lands and to discourage the mowing of roadway verges there. This type of action is popular in the UK as well.
And the Eastern United States Migration?
Here we run into a dearth of data….because of Covid! The usual data sources: butterfly counts along the migration route north to south were curtailed or abandoned entirely due to (unfounded) fears of being either in groups of humans or even in some cases the fear of being outdoors.
Last November, Monarch watchers east of the Rocky Mountains had mixed opinions on how the season would turn out.
“Karen Oberhauser, founder of monarch butterfly citizen science organization Monarch Joint Venture and professor of restoration ecology at the University of Wisconsin-Madison, said she’s cautiously optimistic about summer breeding activity and anecdotal reports of high numbers seen during the fall migration. “I hope … it translates into good numbers in Mexico,” she said.” [ source ] In the same report, “Chip Taylor, founder of Monarch Watch, was less enthusiastic and suggested that the eastern monarch migration population will decline this year. He pointed out that late migrations historically make for smaller overwintering populations.”
The usual sources of census data for the Eastern Monarch Migration have been silent the last 2 years – figures are usually published in February by Mexico’s CONANP – Comisión National de Áreas Naturales Protegidas. Last year there was not official announcement (that I could find). The Monarch Sanctuaries in Mexico were officially closed to visitors because of Covid. I am not sure how this prevented the rangers and researchers from performing their usual census, but either they did not do so, or it is running late.
The latest population data for the eastern migration is from the winter of 2019-2020:
I am attempting to get an official number for the 2020-2021 season – but have had no luck so far. The best I have found is a comment made by Monarch Watch’s Chip Taylor in his post on the 6th January 2022:
“Last year my estimate for the hectare total was almost spot on – 2.0 hectares vs a measured 2.01 hectares. It was more of a guess than a data-based prediction, but I’ll take credit for being close. There are reasons to think I will be close again this year and other reasons to predict that the number will be higher.” (said while predicting another drop in population for 2021-2022).
I have information from local Monarch researchers in Mexico who report that CONANP may release a census soon (it has not as of 20 March 2022).
I can only offer this good news from an eye-witness account:
“But in our estimation, in the Cerro Pelón Sanctuary, there was doubling of the butterflies from last season.” (personal communication — paraphrased for language differences)
Cerro Pelón Santuario (or reserve) is only one of the locations where eastern migrating monarchs roost in huge masses to overwinter. It located in the mountains about 60 miles northeast of Mexico City:
Other major monarch reserves are all located in the same general area. Cerro Pelón is shown in the middle. The major roosts are within the yellow area, with minor roosts scattered around in the buff region shown.
So we have an encouraging but partial and unofficial report from the scene in Mexico, which gives us this general picture:
If our unofficial estimate for this year is correct and verified, eastern monarchs are making a slow but steady comeback. When and if CONANP releases an official number, I will make an updated report.
Bottom Line:
The Western Monarch Migration, which just last year was predicted to vanish completely, has pulled a marvelous “rabbit-out-of-a-hat” trick on all the nay-sayers, doom promoters and all-is-lost-ers. Experts and advocates are entirely thrilled and mystified by the 100-fold increase in roosting monarchs in the 2021-2022 winter. Seeming absolutely impossible to some experts, a mere 2,000 surviving migrating monarchs, only a percentage of whom could have been female, apparently managed to breed the population up to 250,000 in a single season (which is composed of several generations).
The Eastern Monarch Migration is shrouded somewhat in the fog created by the Covid pandemic with official census numbers missing and/or unreliable. Opinions from monarch expert in the United States range from optimistic to pessimistic. Partial information from on-the-scene experts at Cerro Pelón gives us hope that things are at least holding steady.
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Author’s Comment:
The news from California is intriguing and the confusion of the experts terrifically amusing. I think many of the experts were counting on being able to say “We told you so! Now the western monarch migration is extinct and it is your fault.” [ here and here ]. Early on, with the Thanksgiving Monarch Count in California, things were looking good, but experts were still moaning and denying recovery. I hope to find time to write a longer piece detailing the conservation efforts underway, the speculation on the biologically impossible surge in the population and other fascinating aspects of this larger story.
Our on-site reporter is Joel Moreno Rojas who operates the JM Butterfly B&B in Macheros, Mexico, adjacent to the Cerro Pelón reserve. “The business quickly turned Macheros into a popular butterfly tourist destination. …. directly employing more than a dozen people as guides, translators, cooks, servers, drivers and housekeepers in winter, as well as 3-4 construction and maintenance workers year-round”. Maybe next winter, I will go and stay for a week or two.
POST-PUBLICATION NOTE: Joel Moreno Rojas has established a non-profit “Butterflies and Their People”. They approach the problems of protecting the Monarch this way: “Logging causes habitat loss in the Monarch Butterfly Biosphere Reserve. But people continue to log because they have no other economic options. Our project addresses both issues by hiring local people to protect the butterfly forest. The fate of the monarchs and that of the people who live alongside them are intimately interconnected: we cannot safeguard one without safeguarding the other.”
In the meantime, this spring remember to plant a few native milkweeds in your flower garden. If you belong to a local conservation group, get them to advocate for the state and country road maintenance departments to spare roadside milkweed patches. If you have young children (5-15), search out monarch caterpillars, capture and raise them to maturity and let your kids witness the miracle of the caterpillar-to-butterfly transformation. There are instructions online. Once the butterfly has emerged and the wings are fully dry, release the butterfly onto nectar-producing flowers in your garden. Be aware – it will fly away in a day or so – so make sure your kids know this in advance.
Nature is full of surprises!
Thanks for reading.
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Well, Lorenz did keep telling people about butterfly wings!
IanE ==> Yes, and he was quite right — in a tongue-in-cheek way. I wrote a piece at Juith Curry’s site years ago: Lorenz Validated
We have several milkweed plants in our SoCal yard. Both in 2020 and 2021 we had at least 20 or so successful chrysalis hatchings…hatching… I think their “2000” surviving is insanely low…unless we had 1% of the population just in our backyard.
Hatchings hatching??
Guess my inner Kamala Harris came out sorry
Eric ==> Eggs hatch.Butterflies (and other things) emerge from a chrysalis.
Eric ==> It was not the number of monarchs in total, but only those roosting at overwintering sites that was remarkably low. And it is only the Western Migration that all the worry was about. The general population of Monarchs west of the Rockies has never been in any danger or had a worrying low population.
My first guess… last winter when they counted only 100, the butterflies were overwintering in places people were not looking for them. End of story.
In east Toronto there is growing interest in gardens which encourage butterflys. I have even noticed that milkweed has shown up in city flower gardens. Whether that is done by city employees or clandestinely by local citizens is unknown to me.
It’s fun to imagine that such actions could have had such a positive effect
Timo, NTO ==> There are many absolutely beautiful native milkweeds that make great flower garden background plants.
I have planted some at our home.
Thanks for the link. Growing up in Northern Michigan I only knew of one kind of milk weed.
mkelly ==> That’s what most people (except dedicated gardeners) experience — the local weedy milkweed. In most cases, that’s only one of the milkweeds that could grow there and be beneficial for monarchs.
Plants a half dozen different natives and we’ll see more monarchs in the future. Watch for caterpillars. Easy to see — look for leaved with rounded “bites” the size of a human bite out of the edge of leaves (the caterpillars take little bites but they add up to look like a human bite!)
hmm our monarchs have a stage where they look like golden aphids then they go caterpillar then pupate
ozspeak ==> Your swansdown is called “a milkweed” in the literature.
https://bioone.org/journals/The-Journal-of-the-Lepidopterists-Society/volume-73/issue-3/lepi.73i3.a7/Migration-and-Overwintering-in-Australian-Monarch-Butterflies-Danaus-plexippus-L/10.18473/lepi.73i3.a7.short
Monarchs can also survive on Spreading Dogbane.
Bruce ==> Thanks for that. “Spreading dogbane is found in a variety of habitats, from native plant communities to weedy roadsides and waste areas. The flowers produce nectar that is an important food source for insects, most notably the monarch butterfly. In fact, the milkweed family, host plant for monarchs, and the dogbane family are closely related.”
I don;t believe that monarch caterpillars can eat dogbane though. This from another site “Dogbane is a plant that greatly resembles milkweed. It is in the same plant family as milkweed. The problem with dogbane is that Monarch and Queen caterpillars will not eat it.” https://butterfly-fun-facts.com/dogbane/
Kip,
That reminds me of another experience I had worth sharing. When I was in the Army in the late-1960s, I was stationed in Hanover, New Hampshire. My wife and I were driving around observing the Fall colors in the White Mountains in October. We had stopped at a roadside picnic table for a late lunch. It was cold out. I was sitting at the table eating an apple. A butterfly (I don’t remember if it was a monarch or not) flew up and landed on the apple in my hand and proceeded to feed on the juice in the apple. I was surprised at the time because it was my experience that normally butterflies would keep their distance from me. But, at that time of the year I guess it was hungry enough to throw caution to the wind.
Clyde ==> Apple juice is basically nectar…their natural food.
I transplanted a few of the most common east US milkweed (Asclepias syriaca) in front of the house and got this last summer.
beng135 ==> Great! Keep up the good work.
The Painted Lady butterfly also migrates long distances, wintering in central Africa and summering in Europe (somehow making it across the Sahara both ways!).
https://www.sciencedaily.com/releases/2019/09/190904100743.htm
beng => Yes, the European version (sort of) of the North American Monarch migration. The Painted Ladies do not, however, roost in masses in Africa. Their story is not as clear as with the Monarchs, and is still a subject of study:
https://www.britishecologicalsociety.org/painted-ladys-butterfly-migratory-flight/
My wife proved that milkweed is a limited resource. Now I give her credit, the species of milkweeds she selected and planted produced pretty plants. But… Everything we read said to thin the eggs, before they even hatch. We found out why. We seemed to go from a half dozen cute little striped worms to a denuded plant with a couple of dead striped worms fallen to the ground beneath it in just a day or so.
I think if you remove just about every egg you see (except maybe one, just to make sure), the ones you don’t see will be just about the right population to reach chrysalis stage maybe about the time they eat the last leaf.
Red ==> Yes, your wife may have been planting the more decorative tropical milkweeds. And, if she has planted just one or two, and there are no other milkweeds around, then the butterflies will lay too many eggs on the few available plants — and too many caterpillars will eat up all the available leaves.
Solution suggestions: Plant more milkweeds, native milkweeds.
The definition of the word expert – in the 21st century – is someone who doesn’t know their @rse from their elbow; but they do know their politics.
fretslider ==> Generally quite true. In this case, the experts are good people trying to understand a subject that can be discouraging — monarchs have taken a real hit from the shift to widespread conversion of pastureland to cropland — and just the normal chaoticness of population dynamics.
The very fact of the monarch migration itself is a wonderful puzzle to spend a lifetime tying to understand.
I’m not an entomologist, but I know a Monarch butterfly when I see one, and I saw the most that I have even seen this past summer in Colorado, east of the Rockies.
I have been gardening for years and I find a lot of butterflies and caterpillars do things differently than what the experts claim they will. Not a lot differently, but a little.
Skeptic ==> That is certainly true — of all species. Even common descriptions of many species have wild variations — in birds, there are many non-conforming feather color patterns — my wife sees them often at our feeders.
Scissor ==> Yes, that is the general case — monarch watchers last summer and fall reported many more monarchs than the few previous years — breeding success was evident.
However, migration success depends on a lot of additional factors, The Super Generation (the one that undertakes the migration) has to fly all the way to Mexico — through drought areas, hurricane rainfalls, high winds, areas lacking blooming flowers, hail storms, ….you get the idea. So some years, good breeding success does not lead to good numbers arriving in Central Mexico.
Kip,
Many, many thanks for this piece.
You cannot imagine the number of my friends and acquaintances who are certain the Monarchs are halfway to extinction.
I will be sending a link to this piece to every last one of them.
John ==> You are welcome — as was the news of the Western Migration. The monarchs are hampered in their success by dependence on a SINGLE plant for breeding — the milkweeds. They have kind of boxed themselves in with that. Milkweed is perennial and a very successful self-repolanter — spreads seeds everywhere and they like scrappy ground . But, humans don’t like mildweeds– considering them weeds, so we cut them and poison them.
Fight back – plant lovely milkweeds in your garden — there are many fabulously beautiful vaieties.
Is there a particular type of milkweed upon which Monarchs feed?
Retired ==> The basic requirement is that the milkweed be a North American native milkweed. Search on the ‘net for “native milkweeds” and you’ll be surprised about how many there are and how beautiful they are .
Though monarchs can feed on “tropical” milkweeds, natives are better say the entomologists.
Milkweeds were common in northern Illinois when I was a boy. I have yet to see any here in SW Ohio.
Clyde ==> You wuld have them if they quit mowing them. Look on disturbed land — road verges, hiway sloped verges.
So the butterflies are ignoring the climatards, too. Smart bugs!
2hotel9 ==> There are stupid, having brains smaller than pinheads. Despite their stupidity, one generation each year can find its way from Canada to a few acre plot in Central Mexico without the aid of a GPS.
Or a smartphone to call home with.
Ducks Unlimited (DU) started out with the aim of protecting the wetlands needed by migrating waterfowl. link
When I go to the American DU site it looks like the original goal is still operating. ie. there’s useful information on how to train your retriever.
When I go to the Canadian DU site … oh dear … so sad.
There is the Iron Law of Bureaucracy which states that an organization will be taken over by people not dedicated to the original goals of the organization but by those dedicated to the continuation of the organization. ie. the people who actually care about something are replaced by people who want to make a living looking like they actually care.
Environmental groups and professional environmentalists have found that they can make more money by pushing doom and gloom. I just tripped over this dandy analysis of how it works.
That’s a pretty good description of the climate industry. The most recent example is, of course, the wuflu. Any possible treatments were aggressively suppressed because they would get in the way of the chosen solution, vaccines. Follow the money on that one for sure.
commie ==> Yes, National Audubon is another example. Caims every bird is endangered or about to be so. Mostly collects money.
National Audubon however does do BIG conservation with a small portion of that money collected (and they collect BIG money).
Local Audubon chapters are terrific and do good work on a local level.
A universal truth: All movements start out as a legitimate cause/need; then become a business; then become a racket. Think about any movement over 20 years old.
I am a butterfly/caterpillar fan and watch many different species closely I find that many, while they strongly prefer one plant, will sometimes eat a different plant if they favorite is not available. Maybe monarchs are able to sometimes eat a close milkweed relative? I also know many people have been planting milkweed to try to help monarchs, so perhaps their favorite plant is spreading.
Skeptic JR ==> Monarchs will eat the nectar of almost any nectar producing flower. But the caterpillars MUST have milkweed. They tolerate “tropical” milkweeds which are more commonly planted in flower gardens but there is evidence that they don’t thrive on the tropicals because of a common parasite: see https://xerces.org/blog/tropical-milkweed-a-no-grow.
I was reading this a couple of days ago
https://www.dailymail.co.uk/sciencetech/article-10590877/Swallows-no-longer-migrating-6-000-miles-South-Africa-staying-Britain-winter.html
Ben V ==> Well, yeah. A dozen or so swallows stayed in the UK. Interesting though — why travel 6,000 miles if there is enough food and comfortable shelter where on is? Birds are not slaves to their instincts or their instincts are not what we believe.
Some monarchs as well are happy to live in Florida and Georgia and other southern states rather than produce a Super generation that migrates to Mexico. And the same out West. Many monarchs move to Beverly Hills and Thousand Oaks and Palm Springs!
Same thing with Robins in Edmonton, Alberta. Some now hang around all winter favouring relatively warm microclimates and feeding on the freeze-dried fruit on the trees and bushes in gardens and street plantings. I would assume these year-round residents get first dibs on the best territories in the spring, so being tough enough to survive an Edmonton winter (and lazy enough not to migrate) would be selected for.
Place called Lake Nipissing – east side of the great lakes. The city there (North Bay) has a water ‘treatment’ plant in the one area right on the lake, you’ll find ducks and geese there all winter long, they know that that spot always stays open (unfrozen) and people feed them, have been for decades, they’ve adapted to it quite well.
ldd ==> Yes, there is a power plant in Florida where the warm water discharge attracts manatees for the winter.
I see the Graun us getting it hopelessly wrong again. They really are comedy gold.
Andrew ==> The Guardian is a member of the Climate (Bad) News Cabal and intentionally by Editorial Narrative edict exaggerates all news that might be spun into anti-human climate crisis or environmental crisis form.
True dat
The fact that I’ve spelled “is” incorrectly is apt for a comment about the Grauniad
It would be interesting to find out what, if anything, uses Monarchs as food. Maybe a cause and effect link there?
Oldseadog ==> Some birds eat monarchs, but the general understanding is that because of the caterpillar diet of semi-poisonous milkweed, the butterflies are distasteful to most birds. They do have other enemies: https://www.monarchparasites.org/monarch-enemies
But none stand out as answerable for the rise and fall of monarch numbers.
Kip: I was told that the Viceroy butterfly copycat enjoyed the birds attitude to that orange color.
https://butterflywebsite.com/gallery/viceroy-butterfly-pictures.cfm
Gary ==> So we are told — that is what “mimicry” is hypothesized to do. It may well be entirely a beneficial accident.
Kp, you report:
> “…overwintering known sites along the southern California coast from Monterey south to San Luis Obispo.”
I can tell you that the southern extent of regular Monarch overwintering is Montecito or even Carpenteria.
Dawg ==> So you live nearby? I fought flooding in Carpenteria in the winter of 68 (I think, it was the 60s).
Actually, there are roosting sites all the way to San Diego — the the main concentration is Monterey to San Luis Obispo.
My BiL has a few acres on the beach across from the polo grounds. They have a line eucalyptus along the cliff. Sometimes those are so crowded with Monarchs they appear orange. Quite a sight to see 100ft tall trees covered in butterflies.
Rob ==> Ah, those lazy hazy California days….my friends and I came down from UCSB to fight the flooding — and in the end re-routed flood water that had been directed int a Latino neighborhood by the Staties. We sent it down Hwy 101 into the business district by commandeering a truckload of sandbags and doing a little creative adjustment to the raging water coming off the hills. Quietly slipped out of town…..
At least the last mudslide (Jan 2018) was woke enough to be an equal socio-economic destroyer. The loss of life and property is regretable. Hopefully lessons were learned not least of which is preventative wildlands management.
I suspect the range of the Monarch overwintering is limited by the development and micro-climates from Ventura to Malibu especially the frequent winter wind events across the Oxnard Plain. IIRC the area around the Scripps Institute in La Jolla is a winter home these beautiful creatures.
The Dawghaus near Camarillo has the necessary milkweed and is blessed seasonally.
Gawg ==> Guess being in the Dawg-house for you is a good thing,
Not to brag but after the blizzard of April ’83 in New England made the commitment for me. I dropped of my thesis that fall, borrowed $200 from my uncle and traversed every state on the Eastern and southern coasts to end up in Soviet Monika. A short skip west to Ventura County found arguably the best climate on the planet. Never looked back.
Dawg ==> UCSB for me in the late 60s. No time to get an education — too much protesting and dropping out. Ran oiff to se soon after, missed the Santa Barbara Sheriff’s Department raid on Isla Vista (with armored troop carriers….),
Admirable that anyone at UCSB in the late 60s even remembers the time. Good on you. 😉
Rob ==> Onbly vaguely — and I didn’t burn the Bank of America … as far as I can remember.
Sounds like the Winter of ’64.
Clyde ==> The Souhern Californbia coast gets hit by those atmospheric rivers over and over, and the mud and houses slide down to the sea. My experience must have been 67 or 68.
> “But in our estimation, in the Cerro Pelón Sanctuary, there was doubling of the butterflies from last season.”
I’m no Spanish speaker, but I’m curious about the Spanish phraseology of this report. In English the word “to redouble” can mean “to double” but usually means “to augment” in the sense of the Spanish “aumentar” or “incrementar” although, according to https://www.wordreference.com/es/translation.asp?tranword=redouble, “redoblar” exists, too, along with reflexive (non-transitive) forms “redoblarse” and “intensificarse.” These are figurative uses. The English word “to double” is directly translated as “duplicar” or “doblar.” Going the other way, I would expect a Spanish speaker explicitly to use “duplicar” to mean “to double,” not “doblar,” which also means “to bend or fold in two,” but that’s just me.
CRhode ==> Good to find someone who understands the problems of translation. In this particular case, the original language of the writer was Spanish, but the necessity of paraphrase stemmed from his writing in English which produced odd syntax — which I then paraphrased into a more usual English sentence. Joel speaks good English.
According to what I have read the migration from Mexico and back is multigenerational. Three generations required at a minimum for the round trip. So no single butterfly makes the whole rotation.
rah ==> Absolutely right….three or more generations going NORTH, but only ONE generation coming South. No monarch makes a two-way migration.
The multi-generational aspect of the monarch migration is truly one of the most astounding and mind-boggling mysteries of nature.
The single generation (of three or more) that makes the astonishing Southbound trip is obviously hard-wired to perform the navigational and physical feat. The geneticists have yet to figure it out.
It is just amazing.
John ==> Quite agree. Several generations each make part of the northern trip, and then ONE generation makes the entire southern trip plus the winter roosting and heads north in the spring. Incredible!
With so few neurons to code the navigational path!
I have been observing migratory bird movements in Southern Alberta since I was a kid. I’ve noted the number of overwintering ducks, geese, eagles and other bird species steadily increased as Southern Alberta winters became less lethally-cold through the 1980s. It is obvious to this practical engineer that the birds, given the ability to survive winter in Alberta vs. expending energy and risk to birdshot strikes to fly south, have chosen the easier of the options. Comparing this to the butterflies, it makes sense that these animals have also figured out the easiest way to survive is to stay put if they have all they need locally.
It therefore seems absurd that biologists would be so determined to force animal behaviours simply to please themselves. The butterflies will figure things out on their own, as this article clearly indicates.
Now, if people want monarchs in their gardens for their own enjoyment, that’s another, perfectly acceptable desire. But it shouldn’t be tied to the survivability of the species, IMO.
Brent ==> Quite Right !
Monarchs rarely make the flight into central Alberta and can produce one generation over the summer – I had them once in 10 years in Edmonton. I would guess that pretty much most animals that are able migrate are pretty flexible. If you consider the glacial epochs and alternating warmer interglacials that have been present for the last several million years, then you would quickly realise that they must be highly flexible. Unless you are a dyed-in-the-wool Climate doomster that is.
Same w/Canada geese — used to migrate from here in east US at least to coastal areas & often farther south, now many are year-long residents here, staying around ponds, lakes and rivers.
beng ==> Give those geese a hard snowy December and they move further south where they can find open fallow corn fields and grasses uncovered by snow.
A bit off topic, but my only observation about Monarchs is this, after spending a good deal of my life in the boreal forest of Canada. When walking along bush roads or trails, it’s common to see bear droppings, usually positioned precisely in the middle of the trail. And in mid-summer, it’s quite normal to see a pile of bearsh*t covered in up to a dozen Monarchs; I presume they are feeding off it. In a good berry season, bearsh*t is full of undigested blueberries – is that what attracts the butterflies?
Smart ==> The topic is “butterflies” so you’re good.
As the question is indelicate, I’ll just give the link:
https://www.nationalgeographic.com/science/article/butterflies-behaving-badly-what-they-dont-want-you-to-know
Recent study documents loss of habitat for eastern Monarch populations 2008 – 2016. Good to see signs of recovery indicated at the Mexico Monarch Sanctuaries.
Cropland expansion in the United States produces marginal yields at high costs to wildlife
Published: 09 September 2020 in Nature Communications
https://www.nature.com/articles/s41467-020-18045-z
“Here we assess annual land use change 2008–16 and its impacts on crop yields and wildlife habitat. We find that croplands have expanded at a rate of over one million acres per year,”
Monarch habitat loss : “We estimate that ~220 million (SE ± 189) common milkweed stems were lost due to conversion of grasslands, wetlands, and shrublands to corn and soybean production across the Midwest during our study period. This loss represents 8.5% of the estimated regional total in 2008. The largest reductions occurred in the Dakotas, Iowa, and Missouri”
TedL ==> Yes, the monarchs are restrained by the availability of milkweed for caterpillars.
Plant it in your garden!
I’ve seen Monarchs in Hawaii, They don’t migrate.
Gerald ==> Yes, monarchs have established populations in many parts of the world — and live year around in most of them. The two North American migrations are unusual.
There are other butterflies that exhibit migratory behavior. https://www.gardenexperiments.com/monarchs-butterflies-migrate-north-america/
The Monarchs (aka Wanderers) in eastern Australia do migrate, or at least some do, although not as spectacularly as in North America. Where I live in the Sunshine Coast Hinterlands, I see Wanderers year round and it is a rare week I don’t see at least one. Our Monarchs are thought to have blown in with a cyclone from New Caledonia (where they had been introduced) in the 1870’s – and they found a paradise of milkweeds ready to eat.
DaveW ==> Yes, you are right — “but not as spectacularly as in North America”
For readers with interest:
https://australian.museum/learn/animals/insects/wanderer-butterfly/
Oh no.. Monarch butterfly numbers increasing..
This is all because of “Climate change”, you know.
Its a portent of DOOM !!! 😉
A few years ago I contacted a professor at Texas A&M that studies Monarchs. I had what turned out to be unfounded concerns about the height of urban structures. I also commented on my livelong observations around Temple, TX. How what used to be native fields are now subdivisions and how I can still find milkweed along rural roads right next to cropland. No milkweed can be found in what is now manicured green lawns in those new subdivisions. This professor’s main concern about Monarchs wasn’t the use of herbicides on cropland. It was the lack of food and water for Monarchs in cities. He said the real risk was Monarchs having to fly over miles and miles of concrete and asphalt. They fatigue and starve before they get across huge cities.
Myron ==> An odd concern — bet they just fly around those cities. But as a boy in Los Angeles (one huge city for miles and miles and miles…..) we had monarchs.
Quote:”This type of action is popular in the UK as well.
Following the link in there, to the Grauniad, reveals lots of things about UK folks – or certainly the finger wagging guilt inducing domineering know-it-alls. Esp about climate.
They suggest not cutting the roadside verges……
It is entirely obvious that the only roadside verges they *ever* see are urban and suburban roadside verges.
Verges out in the countryside are NOT ‘manicured like lawns‘
Verges in towns and cities are kept as short as they are in a deterrent to folks who throw/drop litter.
It shames them into not doing it – whereas with overgrown verges, packets, cans, papers, bottles etc etc simply disappear instantly and the perpetrators think they can get away with it
Graunidians then assert that the uncut verges will become wildlife havens.
OK, yes they will and they’ll occur as pairs – one down each side of the road.
In peasant farmer vernacular = The Long Meadow.
Cows and sheep love them
But critters on one side of the road will always be tempted to venture across to the other side.
And get splattered in the process.
(The ancient and really crap joke:
Q: What’s the last thing to go thro the mind of a (butterfly) fly on a motorway.
A: Its arse)
Same applies to Bambi, hedgehogs, little birds, cows, sheep, pedestrians etc.
Bees & butterflies not very least.
Certainly some verges out in the countryside are cut BUT, because roadside verges are so lush and verdant, they quickly become hazards ##
….because of overgrowing herbage narrowing the lanes and making it difficult to see round corners and to get out of junctions
Also, verges becomerefuges for noxious and notifiable weeds, such as Creeping Thistle, Spear Thistle and especially Ragwort (aka; Bowens, Tansy, Stinking Willy) so verges will be cut to prevent things like that setting seed thereafter hitching rides nationwide.
(In the UK, if you allow a ‘Notifiable Weed‘ such as those to set seed and spread to a neighbours land – you can find yourself in Some Very Deep Shit)
Thus, Dear Grauniad Readers, where roadside verges have been cut in the UK, it is *always* for good reason.
## Roadside verges, certainly in the UK are a gorgeous example of Global Greening and how the omnipotent NASA, just like the Grauniad, have got it more wrong than a really wrong thing
Because, the observant traveller will notice how massively lush, green and abundant the verges are, especially compared to the fields they might be passing by at the time.
Surely Shirley, what with all the care, love, fertiliser, pesticide and general manicuring the fields get, it *should* be the other way round.
Why *do* the verges grow so much better and stronger than the fields?
Because *all* the things generally regarded as ‘pollution‘, dust, soot/smoke, brake dust (esp metal ‘dust’ off disc brakes) tyre dust, the Oxides of Nitrogen & Sulphur and endless other smut…..
…. all act as fertiliser.
Carbon Dioxide is not any sort of fertiliser (Liebig Limiter) for any plant life out in the wild on this Earth
CO2 only becomes a fertiliser inside the insanely pampered world that exists inside commercial greenhouses
“For any closely watched annual natural phenomena to increase by 100 times in a single year is more than a little unusual. ”
See this out of “Insect population Ecology” Varley Gradwell & Hassel (P137)
[Logarithmic Y axis]:
Chas ==> Great image — great reference.
Not unusual to me — but to most people.
I grew up in San Francisco in the 1950s. As a kid I remember seeing monarch butterflies literally cover the sidewalk, parked cars, and the street as they moved north. Local trees would be filled with them at this time. There were blizzards of butterflies.
goldminor ==> Great memory, thanks for sharing.
Well, good news on the Monarchs, although it isn’t really clear how much of a ‘natura’l phenomenon the massive migrations in North America are. They may be a ‘disclimax’ resulting from human modifications to the landscape in the post-colonial period. Who cares, though, it is a wonderful attraction to nature for people of all ages. Anything you can do to stop your local councils from cutting or spraying all the weedy milkweeds will help and plant them in your garden too – many have very attractive flowers.
Here in southeast Queensland I can report that another magnificent butterfly, the Richmond Birdwing (Ornithoptera richmondia), seems to be responding to conservation efforts – mostly at the local level. The largest of all the local butterflies and once one of the most common, populations were drastically reduced by clearing and removing the vines on which their caterpillars depend (and also the introduced Dutchman’s Pipe Vine – a garden ornamental which attracts the females to lays eggs but does not support the development of the caterpillars).
Now, after decades of school children planting out Richmond Birdwing Vines, the relic populations seem to be responding and recolonising areas from which they had been extirpated. A complicating factor is the weather – this has been a very wet and lush La Niña year and the vines have been responding very well (mine has grown all over the place) – so no guarantee we will see them when the rains move on. Still, the adults have been sailing through gardens and leaving eggs that develop into caterpillars that pupate even on the relatively small vines in the gardens.
DaveW ==> Thanks for the good news on Aussie Richmond Birdwings….next time I’m down there, I’ll look for them.
Kip: Certainly the Great Greening is a factor. Maybe monarchs get something from elevated CO2 besides more productive and luxuriant milkweed. Arid areas are greening making more territory available.
The Bengal tiger is also coming back strongly. It has reversed its decline in the Ganges delta, and in India across the border, conservationists report a 6% annual increase since 2006.
Maple syrup in my area is even cheaper and on sale frequently. The magic molecule is is surely at work here.
Perhaps you might check the honey bees. The recent silence suggests they, too, are liking the Greening.
Gary ==> The Great Greening must be helping milkweeds generally — but the biggest problem they have is that they are perennial weeds and grow in disturbed ground naturally — this means in practicality, edges of fields, road verges, fallow pastures. It seems humans don’t like the weeds and mow them down, poison them in corn fields, etc. At least those that are allowed to grow will grow better under slightly higher CO2.
The Tigers however, are having a comeback for the same reason most large mammals (larger than a cat, say) are coming back — laws have been passed and enforced forbidding the killing of them. Once humans stop killing a species, it recovers.
Maple syrup, as you know, depends heavily on weather — particularly in the Spring. Maple sugaring needs just the right combinations of cold nights and warm days to allow humans to tap the trees and get more sap. My son taps here in the Hudson Valley of NY, and has had a good year as well. Greening obviously helps the maple trees proper and thus put down more sugary sap into the root system in the Fall.
Honey bees have another story. Colony Collapse Disorder “CCD isn’t as common as it once was. Beekeepers still see colonies that collapse, but it’s rare,” says Kim Flottum, a beekeeper, author and cohost of the “Beekeeping Today” podcast. Recently retired, Flottum also edited Bee Culture Magazine for more than 30 years. ” https://www.hobbyfarms.com/colony-collapse-disorder-update-2020/
I do not believe there ever was a real problem with wild honey bees — only among the ~ 3 million human-managed hives in the US.
“<i>agricultural practices to suppress weeds and the widespread mowing of highway verges</i>”
Just a guess, do not Monarch butterflies and their annual North American migration pre-date agricultural practices, weed suppression, highways, and mowing?
John ==> Yes, that is the general understanding. But the massive roosts in Mexico were only discovered in the 1970s.
The mowing and weed suppression reduce the number of milkweed plants available for monarch egg laying which leads to lower reproductive success,
Thus there are fewer millions of monarchs found at roosts in Mexico than two decades ago. Or so the story goes.
Given the similarity of geographically limited breeding grounds, it’s a good thing Monarchs aren’t a human food source like Passenger Pigeons were….
For Monarchs, a virus or other disease that would explain their large population decline and recovery as immunity develops seems to be unresearched.
DMacKenzie ==> Yeah, maybe, but the biologists have been actively working on it for some time and haven’t reported any new virus or disease (there are plenty of parasites, etc already known).
As a kid I went to Memphis to a convention with my parents. I remember looking out th window of the hotel room watching butterflies use the updraft up the side of a. high rise to gain altitude and then fly across the Mississippi towards me. There were 100s if not 1000s of them doing it.
Rah ==> Spring or Fall? Wee they going North or South?
Great image — a butterfly elevator.
weird yours move in spring
aussie ones here are around now and laying as we go into autumn
down here theyre laying on a plant we call swansdown has faux spiky pods that pop n puff what looks like bird down around the seeds
ozspeak ==> Your Swansdown is in the same family as the milkweeds and contains the same poisonous substance as milkweeds. They look the same and have the same seed pods and fluffy seeds.
ozspeaksup – Here in Queensland we call swansdown the balloon cotton bush and there is a narrow and not so narrow-leafed species, Gomphocarpus fruticosus & physocarpus. They used to be placed in the same genus as the North America milkweeds, but botanical nomenclature has marched on. Balloon cotton bush are from Africa originally.
Common names sometimes persist, e.g. Redhead Cotton Bush, Asclepias curassavica, is still a milkweed, and better known as Bloodflower. I let the cotton bush go on my place for the Monarchs and for the native Lesser Wanderer. I’ve been meaning to get some Bloodflower for the garden – it is very attractive – but it needs a wetter site than I have to do well.
Funny, my dad has a billion years of National Geographic lying around, and I believe it wasn’t until 1974 (I think) that they even found where in Mexico monarchs wintered.
Caligula ==> Quite Right, Slim!
Quite a naturalist/detective story that!
I live in an avian migratory path. At this time of year, it is splendid.
I always plant loads of annuals to attract bees and butterflies on my large patio deck. Flowers everywhere.
Throughout the years, I’ve noticed a steep decline in monarchs munching on my flowers. It’s depressing, in a way. Last year, I only saw three. And I live outdoors from early morning to late at night. I once saw six monarchs after one plant some seven years ago, and monarchs non-stop every day. No more.
Those are my observations.
Cool ==> Monarch numbers locally (in any particular place) vary widely year to year. This is well established.
Do you have milkweed — native decoratives?
Thanks for the article!!! I don’t do any kind of census count, but I do shoot lots of photos of butterflies and moths, and teensy-weensy insects that most people don’t know exist.
I will be on the lookout for the eggs, caterpillars, and those emerging from their sleeping bags (chrysalis, if you don’t understand), because there is an enormous acreage of forest, marsh, and prairie in my county that is designated wildlife habitat. This includes the butterflies and moths. I don’t do census counts or anything, but I appreciate the heads-up on this!! I might even send your guys pictures.
Thanks!!!!!
Sara ==> I spent almost ten years in the DR, and did hundreds of photos of tiny tiny flowers and spiders — most;y what I call Shield Spiders (they have multi-colored solid carapaces on their backs.)
Send your best photos to me at my first name at 14.net.
Watch the milkweeds for monarch eggs and caterpillars.
Thanks! Looking forward to Spring – if it EVER gets here!!!! 🙂
My wife and I set about to attract Monarchs here in Virginia, by planting milkweed. It’s their favorite food.
We have every other damned kind of weed growing on our property, but we couldn’t get milkweed to take hold!
Where I am, milkweed seems to prefer dry, sort of “sandy” (loose) soils like praririe habitats, so you could try experimenting with creating a spot that would support the growth of that plant.
Micheal ==> Don’t give up. They need a good start in a large pot to develop a strong root system — then they are unstoppable.
Thanks, Kip and Sara. We will try both of these things.
I’m also trying to get a stand of American Chestnut trees going. I’m so far one for seven, though we just received two live saplings from a nursery in Florida. Wish us luck!
Michael ==> Do you have pure native American Chestnuts or hybrids?
I hoped for years to start to reestablish Amer. Chestnuts here in the Central Hudson Valley of NY, but Cornell has not released their blight immune trees to the general public yet. Now I fear I am too old to get them well established even if I get get a dozen or so.
These are hybrids. I was searching for the same thing you were, but have experienced the same roadblock.
I’ll turn 68 next month, so it will be interesting to see whether I get to sample any of these nuts. My life goal is to see Halley’s Comet next time it shows up (since I caught only a glimpse of it in 1994), and be around to brag about it for at least a year. That’ll put my expiration date at sometime in 2062. It could happen…
My wife and I just today bought 96 acres in Tennessee on which to build our retirement home. I haven’t checked whether American chestnuts can grow there, but I suspect they can. If so, I’ll setting up another stand in the not-to-distant future. With any luck, they will be the blight immune American chestnut, rather than the hybrid.
Oops, I meant 1986, not 1994. Not that anyone would notice…
Michael ==> Don’t give up — contact the breeders at Cornell. Offer your services as a test plot — whatever.
And good luck on that 2062 target…..
Kip,
I remember being on a spring-break geology field trip to Death Valley NM in the 1970s, after a particularly wet Spring. The valley floor was covered with short golden sunflowers with a density of about one flower per square meter; there were one or two large, fat caterpillars on every plant. I don’t know what species they were. They resembled the common striped tomato horn worm.
The point of this is that those bountiful years are infrequent, and if one were to take a census of the butterflies or moths during the off years, one might get quite concerned about their survival. However, when the conditions are right, they take advantage of them.
Clyde ==> yes, nature finds those niche years. Google desert super-blooms….