Beautifully written, as always. Just two things to keep in mind. One, not all Eastern monarchs migrate to Mexico. Some are year-round residents or colonizers northward from the Gulf States and from coastal areas from the Carolinas south. What is at risk is the migration phenomenon, not the species itself, and this is a great departure for classification under the ESA. Two, milkweed is not even close to a critical limiting factor east of the Appalachians. Hundreds of acres go unused every season in MD alone. It's best we treat the Great Plains population as a case unto itself and not generalize nationwide about problems it is (and the West Coast population) is encountering
Thanks, Rick. You're right. I mention those year-rounders lower in the post and the risk -- and listing -- specific to the migratory population. But, yeah, I didn't make it clear enough that some of the easterners don't make it to Mexico. I've tagged tons of Monarchs in the Gulf of Maine (Monhegan Island), with not one recovery. I suspect they're not getting to Mexico. I think there's a paper on this.
The USFWS seems to do well segregating East and West populations in its proposal, especially for conservation measures (critical habitat designations). It doesn't seem to segregate the Eastern from the Great Plains. Could be worthy for comments on the proposal?
Intriguingly, some Monarchs from the Midwest have been known to migrate to Cuba from the US, interbreed with the non-migrating population there, and then not return. Ex-pat Monarchs!
Nicely written as always, Bryan. Most of the monarchs that make it to Mexico come from the midwest. It's true that we have a lot of milkweed here in the northeast, but our monarchs that make to Mexico form only a small part of the overwintering population.
USFWS can designate separate populations of mammals to regulate, but I believe they cannot do so under the ESA with insects. Thus, eastern and western monarchs have to be regulated as a single unit, which is a little awkward given the difference between the two groups.
Thank you for writing about the 'at risk' butterfly most of us have seen. Awareness is a start to caring. For about 12 years, my hubby and I focused our nature studies and travel on butterflies of North America. We didn't spend much time with Monarchs but still came to appreciate the lives and needs of over 1,000 butterfly species we found in their wild habitats. That way I came to appreciate the vulnerability of these insects- the problems they face finding each other to reproduce as adults, the females finding the right plants and places to lay their eggs. And the caterpillars the right foods and safe places to form their chrysalis. Life is hard. We can make it harder or easier for other lives if we know about them and care enough to keep them safe. Thank you for helping stop and think about that.
Thanks, Sue. Yeah, butterflies have been around for 100 million years or so. It hasn't taken us long at all to mess with the trajectory of their lives.
I'll add that the spread and travel of Monarchs to places outside of North America has not always been due to humans. For example in 1870, hundreds of Monarchs were carried to Australia from New Caledonia by cyclone winds. Other weather-dispersals like this have been reported, though not all of them led to permanent populations. Most intriguingly, in the 1870s, Maori elders in New Zealand told European naturalists that they considered the Monarch endemic to their lands, and that the butterfly had been there since long before European arrival. They had their own name for it in their own language: kãkâhû.
The population explosion and following pulse of Monarchs that occurred in the 1800s, during which they traveled across the Pacific as far as China, often with human help, but not always, has never been explained. The mysterious pulse ended before the 20th Century began.
Here's an intriguing paper on the event. This author's findings are a matter of debate, and you can find critiques of this paper, but it's a good starting point.
Thanks for this, Kollibri. Great stuff. I'll have a look at the paper. The USFWS listing proposal is somewhat restrained on Monarch "expansionism." It doesn't go into much detail, other than saying that the Monarchs "dispersed from North America via
human assistance, potentially aided through wind dispersal events."
You're welcome! I did a deep dive into Monarchs as part of research for a book. My subject was actually the different species of Milkweed, but I stumbled across that fascinating bit of history about the 19th century spread. In Monarch-geek circles, I guess this event is well-known but I hadn't heard of it before.
I just emailed you the piece I wrote about Monarchs, in case you're interested. It gets into the pulse story some more, though it's mostly about how Monarchs interact with Eucalyptus and different species of Milkweed.
Thanks, Jenn. I didn't answer it. Very good point. It's something I'll cover in subsequent writing. But, for now, the USFWS proposal is quite specific on the kinds of comments it's seeking. And that might be a turn-off for some folks.
If you head to this link (https://www.govinfo.gov/content/pkg/FR-2024-12-12/pdf/2024-28855.pdf), and scroll to the second page, begin reading under the sub-heading "Information Requested." From that point on, the proposal lists the kind of comments USFWS is soliciting. It's a long list, and a lot of it is designed to solicit more science (and not general support from the public).
It also says, for example: "Please note that submissions merely stating support for, or opposition to, the action under consideration without providing supporting information,
although noted, do not provide substantial information necessary to support a determination." Again, I'll try to illuminate some of this soon.
Nice essay Bryan. I have butterfly weed and milkweed and I've seen newly emerged Monarchs in my yard as well as those nectaring on my flowers. I've also seen them form their beautiful chrysalises the few times I've raised them indoors. But I've never been able to spot the chrysalises in the wild. Any tips for that?
Well, that's a good one, Margie. Some people have sharp eyes for them; most of us don't. Maybe others out there can contribute to this. But I guess I'll mention three things:
1) Start looking when you see big, fat, final-instar larvae, which means others might have already pupated.
2) Get on your knees and crawl around, slowly, looking everywhere.
3) Don't necessarily look on milkweed. They can be other places
Thanks Bryan. My daughter found one dangling from her lawn chair. She doesn't have any butterfly weed or milkweed growing in her yard, so the caterpillar would have to have meandered over from her neighbor's yard that does, right? So that means an extensive area to search for a chrysalis even when you see that final instar caterpillar, I assume.
Well, I don't think they usually go that far. Your best bet is indeed in proximity to milkweed. But, yeah, I've seen plenty of chrysalises on manufactured things like walls and fences.
In my experience, it's entirely possible that the caterpillar came from the neighbors. Where else could it have come from? There is no "usual" place to find them.
I've never had luck finding any when looking for the chrysalises, so I settle for the surprising experience of randomly coming upon them, often when least expecting it.
In the 18 years I've been paying close attention to Monarchs, I have found more chrysalises in our various stove-wood ricks than anywhere else. We also found them fairly regularly when we let our Asparagus spears grow into the huge, feathery shrubs they become (this is also good moth habitat). The foliage is the same color as the chrysalises. Not exactly in the wild, but still fun.
They get restless when it's time for them to leave the Milkweed they've been feeding on, and go up and down the stem until they finally stay on the ground. Then they wander in what appears to be an aimless way that seems like it would waste a lot of energy. Eventually they set off on a non-linear path. I tried to follow one once, but after about 4 hours, I just couldn't anymore. I'm afraid I disagree with Bryan about them staying in close proximity to Milkweed.
Yes, I'm weird that way. I get hyper-focused on something and try to see it through to its conclusion. Following rare turtles was much more engaging. I'm retired, so I have the time to do these things.
I did really enjoy Chittka's book--he summarizes all the amazing findings on bee intelligence and helps you understand how people figured out what's happening in the mind of a bee in a truly scientific way with well conducted experiments. But I'm a science writer currently finishing up my own book about insects so I may have more of a background and interest to appreciate the book than most readers.
Thank you so much. I have heard and read various descriptions of what happens , but this is the clearest explanation I have ever heard. thank you again.
When I read in Notes that you would be discussing Monarchs and the proposal to list them as threatened by the USFWS, I looked forward to your essay. Of course, as always , you did not disappoint. I had already read ; here in VT Phil Scott videoed H706, I do love our governor, but it seems more information needs to become available to weigh the impact of farmer’s crops vs. our pollinators and obviously many other insects. I have attached an article below from the NIH, it is extremely long , in this case, I ended up at ‘Conclusions’ before I finished the data 😊. Really, I did not need anyone to tell me the Monarchs were in danger. I have hiked the same path in every season. This year (NEK) in particular, I wondered were all the Milkweed plants have gone . I did not see any! Since I was a child, I’ve always grabbed a ‘ripe’ one to open and watch the little silk parachutes fly in the wind, carrying off their seed packages . And the Monarchs, not a one .Thank you for including the tagged Monarchs and chrysalis photos, an excellent article!
Thanks, Lor. One of the authors on that paper you offer us here, Andrew Davis, has a new paper out about Monarch loss during the southbound migration. It's really interesting -- and relevant. I'll write about it.
Excellent article Bryan. I have witnessed the decline in my own back yard. In 2020, I had a lot of new marsh milkweed blooming and my yard was alive with fluttering and fighting Monarchs. It was pure joy to look out my window and see so many butterflies flying around in my yard. My neighbors had a Barbecue with friends and family and I came home that day to four women standing at the fence line mesmerized by all of the Monarchs in my tiny yard. This past summer despite having plenty of milkweed, common and swamp, I did not see one caterpillar and logged five sightings of monarchs in my yard. It’s heartbreaking.
Thanks, Lisa. As you no doubt know, numbers can fluctuate a lot from year to year. But, yeah, you're in the core of the Monarch distribution there in east-central part of the continent. It's really a different flight there compared to what we have in the East, and so are the threats Monarchs encounter. As I mentioned in my reply to Lor's comment above, there's a new paper out suggesting that there is increasing Monarch mortality during the southbound migration, owing in large part to lack of nectar sources. I'll be writing more on this!
That is heart-breaking. We had the opposite experience here in southern Maine. We had at least 2 in the yard at any given time between arrival and departure, with up 5 or 6 on many days, despite the drought. We have many wild Common Milkweeds that came up on their own after we stopped mowing. Maybe the wild ones provide more support? Just speculation...
Beautifully written. It is fascinating that after living so many months, the Monarchs get up and commence the Northward Journey before laying eggs. Are the plants they prefer not found where they overwinter in Mexico? Of course with the distances to travel and seasons suitable, time is of the essence.
My son and his girlfriend bought a house in Syracuse, NY, with a big lawn. We visited him in November and went for a walk across fields and into forests. We found milkweed pods and stuffed our pockets with the seeds. In their yard, we let fly the seeds. Hope for Monarchs!
The northward journey is fraught. They start where they have spent the winter in Oyamel fir trees in a mountainous area near Mexico City, then they have to make their way through northeastern Mexico, before they get to any nectar and Milkweed plants (I looked for a reference to put here, but apparently after all these years of study, the route they take is still not known!)
The Wild Seed Project has good instructions on how to grow native plants from seed, if there is no germination from the seed you scattered. Milkweed seed has triple dormancy, so can be a challenge.
as a non-scientific appreciator of monarchs I guess it's not surprising that this essay was particularly interesting to me. It did make me think of the Thoreau's Succession of forest Trees where he described/figured out how it was by using seeds that trees from one place could reappear in subsequent generations in another place, so it seems to be with monarchs who reappear in succession far from where they begin. Or is that stretching the analogy too far?
Here's yet another angle: Monarchs are now far more abundant than in Thoreau's day, when the country (the one that disappointed him so) was largely forested, and lacking as much milkweed as we see today. I'll cover some of this in follow-up writing on Monarchs.
Beautifully written, as always. Just two things to keep in mind. One, not all Eastern monarchs migrate to Mexico. Some are year-round residents or colonizers northward from the Gulf States and from coastal areas from the Carolinas south. What is at risk is the migration phenomenon, not the species itself, and this is a great departure for classification under the ESA. Two, milkweed is not even close to a critical limiting factor east of the Appalachians. Hundreds of acres go unused every season in MD alone. It's best we treat the Great Plains population as a case unto itself and not generalize nationwide about problems it is (and the West Coast population) is encountering
Thanks, Rick. You're right. I mention those year-rounders lower in the post and the risk -- and listing -- specific to the migratory population. But, yeah, I didn't make it clear enough that some of the easterners don't make it to Mexico. I've tagged tons of Monarchs in the Gulf of Maine (Monhegan Island), with not one recovery. I suspect they're not getting to Mexico. I think there's a paper on this.
The USFWS seems to do well segregating East and West populations in its proposal, especially for conservation measures (critical habitat designations). It doesn't seem to segregate the Eastern from the Great Plains. Could be worthy for comments on the proposal?
Intriguingly, some Monarchs from the Midwest have been known to migrate to Cuba from the US, interbreed with the non-migrating population there, and then not return. Ex-pat Monarchs!
https://www.academia.edu/69489230/MIGRATION_OF_THE_NORTH_AMERICAN_MONARCH_DANAUS_PLEXIPPUS_TO_CUBA_By
You've personally tagged 1500 individual monarchs!? What's the tag look like? How is it affixed?
Oh, crap -- I meant to include a photo of a tagged Monarch. Sorry! Here's a bunch of images of tagged Monarchs on iNaturalist!
https://www.inaturalist.org/observations?month=9,10&order_by=votes&q=tag&quality_grade=research&taxon_id=48662&verifiable=any
Lovely narrative. Clearly another issue that will require international cooperation.
Hopeful ... Earth Hopeful!
Nicely written as always, Bryan. Most of the monarchs that make it to Mexico come from the midwest. It's true that we have a lot of milkweed here in the northeast, but our monarchs that make to Mexico form only a small part of the overwintering population.
USFWS can designate separate populations of mammals to regulate, but I believe they cannot do so under the ESA with insects. Thus, eastern and western monarchs have to be regulated as a single unit, which is a little awkward given the difference between the two groups.
Ah, this is informative. Thanks, Ernest. It's something I'll mention in subsequent writing about the proposal.
Thank you for writing about the 'at risk' butterfly most of us have seen. Awareness is a start to caring. For about 12 years, my hubby and I focused our nature studies and travel on butterflies of North America. We didn't spend much time with Monarchs but still came to appreciate the lives and needs of over 1,000 butterfly species we found in their wild habitats. That way I came to appreciate the vulnerability of these insects- the problems they face finding each other to reproduce as adults, the females finding the right plants and places to lay their eggs. And the caterpillars the right foods and safe places to form their chrysalis. Life is hard. We can make it harder or easier for other lives if we know about them and care enough to keep them safe. Thank you for helping stop and think about that.
Thanks, Sue. Yeah, butterflies have been around for 100 million years or so. It hasn't taken us long at all to mess with the trajectory of their lives.
Great article.
I'll add that the spread and travel of Monarchs to places outside of North America has not always been due to humans. For example in 1870, hundreds of Monarchs were carried to Australia from New Caledonia by cyclone winds. Other weather-dispersals like this have been reported, though not all of them led to permanent populations. Most intriguingly, in the 1870s, Maori elders in New Zealand told European naturalists that they considered the Monarch endemic to their lands, and that the butterfly had been there since long before European arrival. They had their own name for it in their own language: kãkâhû.
The population explosion and following pulse of Monarchs that occurred in the 1800s, during which they traveled across the Pacific as far as China, often with human help, but not always, has never been explained. The mysterious pulse ended before the 20th Century began.
Here's an intriguing paper on the event. This author's findings are a matter of debate, and you can find critiques of this paper, but it's a good starting point.
https://www.academia.edu/68141464/The_Columbus_hypothesis_an_explanation_for_the_dramatic_19th_century_range_expansion_of_the_monarch_butterfly
Thanks for this, Kollibri. Great stuff. I'll have a look at the paper. The USFWS listing proposal is somewhat restrained on Monarch "expansionism." It doesn't go into much detail, other than saying that the Monarchs "dispersed from North America via
human assistance, potentially aided through wind dispersal events."
"Wind dispersal events" — classic jargon! :-)
You're welcome! I did a deep dive into Monarchs as part of research for a book. My subject was actually the different species of Milkweed, but I stumbled across that fascinating bit of history about the 19th century spread. In Monarch-geek circles, I guess this event is well-known but I hadn't heard of it before.
I just emailed you the piece I wrote about Monarchs, in case you're interested. It gets into the pulse story some more, though it's mostly about how Monarchs interact with Eucalyptus and different species of Milkweed.
Bryan - I hope I am not asking a question you have already answered but I can’t find out how to comment on the govt’s proposal.
Thanks, Jenn. I didn't answer it. Very good point. It's something I'll cover in subsequent writing. But, for now, the USFWS proposal is quite specific on the kinds of comments it's seeking. And that might be a turn-off for some folks.
If you head to this link (https://www.govinfo.gov/content/pkg/FR-2024-12-12/pdf/2024-28855.pdf), and scroll to the second page, begin reading under the sub-heading "Information Requested." From that point on, the proposal lists the kind of comments USFWS is soliciting. It's a long list, and a lot of it is designed to solicit more science (and not general support from the public).
It also says, for example: "Please note that submissions merely stating support for, or opposition to, the action under consideration without providing supporting information,
although noted, do not provide substantial information necessary to support a determination." Again, I'll try to illuminate some of this soon.
Finally, there's the direct comment federal portal here: https://www.regulations.gov/commenton/FWS-R3-ES-2024-0137-0001
Sorry if this is all a bit complicated. I'll have more on it once I come up for air after writing! But thanks again!
Wow your photo of a Monarch emerging from its chrysalis is just mesmerizing! And I love learning that it weighs less than a paper clip. 🦋
... and it's one of the smaller paper clips (not the big ones)! 😀🦋
Nice essay Bryan. I have butterfly weed and milkweed and I've seen newly emerged Monarchs in my yard as well as those nectaring on my flowers. I've also seen them form their beautiful chrysalises the few times I've raised them indoors. But I've never been able to spot the chrysalises in the wild. Any tips for that?
Well, that's a good one, Margie. Some people have sharp eyes for them; most of us don't. Maybe others out there can contribute to this. But I guess I'll mention three things:
1) Start looking when you see big, fat, final-instar larvae, which means others might have already pupated.
2) Get on your knees and crawl around, slowly, looking everywhere.
3) Don't necessarily look on milkweed. They can be other places
4) Extra credit: get kids to help!
🦋❤️
Thanks Bryan. My daughter found one dangling from her lawn chair. She doesn't have any butterfly weed or milkweed growing in her yard, so the caterpillar would have to have meandered over from her neighbor's yard that does, right? So that means an extensive area to search for a chrysalis even when you see that final instar caterpillar, I assume.
Well, I don't think they usually go that far. Your best bet is indeed in proximity to milkweed. But, yeah, I've seen plenty of chrysalises on manufactured things like walls and fences.
In my experience, it's entirely possible that the caterpillar came from the neighbors. Where else could it have come from? There is no "usual" place to find them.
I've never had luck finding any when looking for the chrysalises, so I settle for the surprising experience of randomly coming upon them, often when least expecting it.
In the 18 years I've been paying close attention to Monarchs, I have found more chrysalises in our various stove-wood ricks than anywhere else. We also found them fairly regularly when we let our Asparagus spears grow into the huge, feathery shrubs they become (this is also good moth habitat). The foliage is the same color as the chrysalises. Not exactly in the wild, but still fun.
They get restless when it's time for them to leave the Milkweed they've been feeding on, and go up and down the stem until they finally stay on the ground. Then they wander in what appears to be an aimless way that seems like it would waste a lot of energy. Eventually they set off on a non-linear path. I tried to follow one once, but after about 4 hours, I just couldn't anymore. I'm afraid I disagree with Bryan about them staying in close proximity to Milkweed.
Thanks for that info and I'm impressed that you followed a caterpillar for as long as 4 hours!
You're welcome!
Yes, I'm weird that way. I get hyper-focused on something and try to see it through to its conclusion. Following rare turtles was much more engaging. I'm retired, so I have the time to do these things.
The animal behaviorist Lars Chittka wrote in his book The Mind of the Bee that he gave up after spending 16 hours following a bee!
Now that's patience! I wonder if he was trying to figure out a bee-line.
Thanks for letting me know about Dr Chittka and his book. I just finished reading an excerpt. Did you enjoy the book?
I did really enjoy Chittka's book--he summarizes all the amazing findings on bee intelligence and helps you understand how people figured out what's happening in the mind of a bee in a truly scientific way with well conducted experiments. But I'm a science writer currently finishing up my own book about insects so I may have more of a background and interest to appreciate the book than most readers.
Thank you so much. I have heard and read various descriptions of what happens , but this is the clearest explanation I have ever heard. thank you again.
Ah, my very intent. You've made my day. Thanks, Leslie!
Thank you (always) Bryan. Just shared on my local Nextdoor page.
Oh, I wish I was there "next door" (eating yummy chocolate and being wistful about the river and the canyon).
When I read in Notes that you would be discussing Monarchs and the proposal to list them as threatened by the USFWS, I looked forward to your essay. Of course, as always , you did not disappoint. I had already read ; here in VT Phil Scott videoed H706, I do love our governor, but it seems more information needs to become available to weigh the impact of farmer’s crops vs. our pollinators and obviously many other insects. I have attached an article below from the NIH, it is extremely long , in this case, I ended up at ‘Conclusions’ before I finished the data 😊. Really, I did not need anyone to tell me the Monarchs were in danger. I have hiked the same path in every season. This year (NEK) in particular, I wondered were all the Milkweed plants have gone . I did not see any! Since I was a child, I’ve always grabbed a ‘ripe’ one to open and watch the little silk parachutes fly in the wind, carrying off their seed packages . And the Monarchs, not a one .Thank you for including the tagged Monarchs and chrysalis photos, an excellent article!
https://pmc.ncbi.nlm.nih.gov/articles/PMC8623494/
Thanks, Lor. One of the authors on that paper you offer us here, Andrew Davis, has a new paper out about Monarch loss during the southbound migration. It's really interesting -- and relevant. I'll write about it.
Excellent article Bryan. I have witnessed the decline in my own back yard. In 2020, I had a lot of new marsh milkweed blooming and my yard was alive with fluttering and fighting Monarchs. It was pure joy to look out my window and see so many butterflies flying around in my yard. My neighbors had a Barbecue with friends and family and I came home that day to four women standing at the fence line mesmerized by all of the Monarchs in my tiny yard. This past summer despite having plenty of milkweed, common and swamp, I did not see one caterpillar and logged five sightings of monarchs in my yard. It’s heartbreaking.
Thanks, Lisa. As you no doubt know, numbers can fluctuate a lot from year to year. But, yeah, you're in the core of the Monarch distribution there in east-central part of the continent. It's really a different flight there compared to what we have in the East, and so are the threats Monarchs encounter. As I mentioned in my reply to Lor's comment above, there's a new paper out suggesting that there is increasing Monarch mortality during the southbound migration, owing in large part to lack of nectar sources. I'll be writing more on this!
Looking forward to it! I’m an island of natives in a sea of turf and non-natives. It’s not enough.
That is heart-breaking. We had the opposite experience here in southern Maine. We had at least 2 in the yard at any given time between arrival and departure, with up 5 or 6 on many days, despite the drought. We have many wild Common Milkweeds that came up on their own after we stopped mowing. Maybe the wild ones provide more support? Just speculation...
Beautifully written. It is fascinating that after living so many months, the Monarchs get up and commence the Northward Journey before laying eggs. Are the plants they prefer not found where they overwinter in Mexico? Of course with the distances to travel and seasons suitable, time is of the essence.
My son and his girlfriend bought a house in Syracuse, NY, with a big lawn. We visited him in November and went for a walk across fields and into forests. We found milkweed pods and stuffed our pockets with the seeds. In their yard, we let fly the seeds. Hope for Monarchs!
The northward journey is fraught. They start where they have spent the winter in Oyamel fir trees in a mountainous area near Mexico City, then they have to make their way through northeastern Mexico, before they get to any nectar and Milkweed plants (I looked for a reference to put here, but apparently after all these years of study, the route they take is still not known!)
The Wild Seed Project has good instructions on how to grow native plants from seed, if there is no germination from the seed you scattered. Milkweed seed has triple dormancy, so can be a challenge.
Brilliant post. I very much enjoyed it.
as a non-scientific appreciator of monarchs I guess it's not surprising that this essay was particularly interesting to me. It did make me think of the Thoreau's Succession of forest Trees where he described/figured out how it was by using seeds that trees from one place could reappear in subsequent generations in another place, so it seems to be with monarchs who reappear in succession far from where they begin. Or is that stretching the analogy too far?
Here's yet another angle: Monarchs are now far more abundant than in Thoreau's day, when the country (the one that disappointed him so) was largely forested, and lacking as much milkweed as we see today. I'll cover some of this in follow-up writing on Monarchs.