Monarch Watch Update May 2022

This newsletter was recently sent via email to those who subscribe to our email updates. If you would like to receive periodic email updates from Monarch Watch, please take a moment to complete and submit the short form at monarchwatch.org/subscribe/

Greetings, Monarch Watchers!

Included in this issue:
1. Monarch Watch Open House & Spring Plant Fundraiser
2. Follow Monarch Watch on LinkedIn
3. Monarch Population Status
4. Monarch Tag Recoveries from Mexico
5. When monarchs are like corn
6. New Project: Monarch Directional Flight
7. About This Monarch Watch List

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1. Monarch Watch Open House & Spring Plant Fundraiser
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Monarch Watch hosted its first in-person Open House and Plant Fundraiser since 2019 on May 7th. An enthusiastic turnout for the presale (online orders and local pickup) and in-person event made it our biggest plant fundraiser ever! In addition, hundreds of visitors enjoyed outdoor family activities and displays, including seed ball making, a kids’ activity guide, butterfly card craft, emergence of monarch butterflies, and lots of caterpillars to see. The Douglas County Extension Master Gardeners were on hand for garden tours and to help visitors choose the right butterfly plants for their gardens and the KU Natural History Museum also participated by hosting a booth.

Thank you to everyone who made this year’s event a success – see you next spring!

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2. Follow Monarch Watch on LinkedIn
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Monarch Watch has established a presence on LinkedIn so if you’d like make a connection and follow us on that platform, head on over to our new page at https://linkedin.com/company/monarchwatch and hit that Follow button!

See you there 🙂

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3. Monarch Population Status
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We are eagerly awaiting the official report from WWF-Mexico with the 2021 overwintering season monarch population numbers and we anticipate we will have that for you in the near future. As soon as the news breaks, it will be reported via our blog and Facebook page so stay tuned!

Monarch Watch Blog: https://monarchwatch.org/blog

Monarch Watch Facebook: https://facebook.com/monarchwatch

In the meantime, be sure to check out the recent “Development of the 2022 monarch population so far” blog post at https://monarchwatch.org/blog/2022/05/18/development-of-the-2022-monarch-population-so-far/

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4. Monarch Tag Recoveries from Mexico
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More than 900 Monarch Watch tags were recovered from monarch overwintering sites in central Mexico during the 2021 tagging season. All of the tags have been examined and the “Tag recoveries from central Mexico” list has been updated. By default, this list is sorted by the report season then by tag code and now includes nearly 21,000 records.

Get out your tag codes and check out the updated list 🙂

Monarch Watch tag recoveries: https://monarchwatch.org/tagrecoveries

As a reminder, it is never too late for data so if you have not yet submitted your records, please do so at your earliest convenience via https://monarchwatch.org/tagging

Thank you to everyone who tagged monarchs in 2021 and also those who assisted with the recovery efforts!

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5. When monarchs are like corn —by Chip Taylor
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I’m going to tell you why and when monarchs are like corn. It’s been on my list to do so for some time. A recent headline gave me the motivation to start this discussion. Let’s start with the obvious, corn doesn’t fly, lay eggs, visit flowers or migrate, but it does grow and every farmer knows that yields are dependent on numerous factors and that two of the most important are timing of planting and temperatures. There’s the similarity – timing and temperature.

The existence of data on both monarchs and corn that can be related to temperatures and weather extremes allows for many comparisons. Similar relationships surely exist for a large number of co-occurring plants and animals.

Explore the complete “When monarchs are like corn” article at https://monarchwatch.org/blog/2022/05/17/when-monarchs-are-like-corn/

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6. New Project: Monarch Directional Flight
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During the spring and mid-summer migrations, there are powered directional flights with no gliding and soaring. Most flight is rapid at speeds of 10-12 mph at 4-10 meters above the ground. Nectaring occurs mostly in the morning and late afternoon. There is some mating and egg laying as these migrations progress. These migrations appear to advance at rates of 30-55 miles per day. In the spring, there are two generations of migrants, the monarchs returning from Mexico have headings that are primarily to the N and NE. This migration generally ends with the death of most of the overwintered monarchs by the end of April. The offspring of the overwintered migrants begin to reach maturity at the end of April and they too tend to move to the N and NE. It is these first-generation monarchs that recolonize the northern breeding area. Curiously, this migration appears to stop at different latitudes as the season progresses northward. This observation gives rise to several questions: do they stop and, if so, when do they stop and why?

Monarch Watch is seeking the immediate assistance of monarch enthusiasts (community scientists) in collecting directional flight observations of monarchs in their area during the spring migration in May and June. Register today to participate!

Complete details are available on the project’s page at https://monarchwatch.org/directional-flight/

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7. About This Monarch Watch List
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Monarch Watch ( https://monarchwatch.org ) is a nonprofit education, conservation, and research program affiliated with the Kansas Biological Survey & Center for Ecological Research at the University of Kansas. The program strives to provide the public with information about the biology of monarch butterflies, their spectacular migration, and how to use monarchs to further science education in primary and secondary schools. Monarch Watch engages in research on monarch migration biology and monarch population dynamics to better understand how to conserve the monarch migration and also promotes the protection of monarch habitats throughout North America.

We rely on private contributions to support the program and we need your help! Please consider making a tax-deductible donation. Complete details are available at https://monarchwatch.org/donate or you can simply call 785-832-7374 (KU Endowment Association) for more information about giving to Monarch Watch.

If you have any questions about this email or any of our programs, please feel free to contact us anytime.

Thank you for your continued interest and support!

Jim Lovett
Monarch Watch
https://monarchwatch.org

You are receiving this mail because you were subscribed to the Monarch Watch list via monarchwatch.org or shop.monarchwatch.org – if you would rather not receive these periodic email updates from Monarch Watch (or would like to remove an old email address) you may UNSUBSCRIBE via https://monarchwatch.org/unsubscribe

If you would like to receive periodic email updates from Monarch Watch, you may SUBSCRIBE via https://monarchwatch.org/subscribe

This e-mail may be reproduced, printed, or otherwise redistributed as long as it is provided in full and without any modification. Requests to do otherwise must be approved in writing by Monarch Watch.

Development of the 2022 monarch population so far

Predicting how the population will develop each year is a challenge. As recently as the 22nd of April, we posted a rather dismal account of the status of the population. This assessment was based on reports to Journey North, iNaturalist and from some emails received from people in Texas. Overall, there wasn’t a lot of reason to be optimistic.

As one who is trying to understand how the population functions, I get into trouble when I rely too much on the available data. There may be another example of such over-reliance in what happened in early May – a dramatic early advance of first-generation monarchs into the summer breeding area north of 40 North. The paragraphs below summarize what I posted to Dplex-L on the 11th of May. That will be followed by a brief account of how this rapid colonization compares with that of other years and what it could mean for the rest of the breeding season.

The big push of 9-10 May 2022

If you follow monarchs closely, you are aware that there have been numerous reports to Journey North of monarchs being sighted north of 40N (roughly the latitude of St Joseph, MO) in the last two days. These sightings are significant for three reasons. First, because this advance represents colonization of the area north of 40N – the primary area that produces the migratory population that reaches Mexico in Oct-Dec. Second, this advance is a bit earlier than usual. And third, this advance was extraordinarily fast.

I have put together some quick notes to provide some context to what happened during 9-10 May.

There were 44 reports to JN in 9-10 May and of those 42 were in the Midwest and N of 40N.

Most sightings were from 41-42N with one at 45.1N

In contrast, there were only 9 reports from 7-8 May with 6 in the Midwest and only 1 >40N

Most sightings (N=13) from 1 May through 8 May in the Midwest were from 38-39N.

There are 69 miles (111 km) per degree of latitude. The calculations are rough, and only provide an estimate, but if we average 38-39N as a starting point (38.5) and 41-42N as the end point (41.5), that means that the population advanced approximately 207 miles (333 km) in two days. That said, 14/44 of the sightings were from >43N indicating that a number of the monarchs may have advanced more than 300 miles in 2 days.

This movement was aided by strong winds mostly from the south and southwest – see below. This rate of advance rivals that seen in early April 2017 when there was a similar wind aided advance that carried monarchs from northern Oklahoma to mid Nebraska, again a distance of approximately 300 miles.

As in 2017, the newly arriving monarchs N of 40N are well ahead of the emergence of milkweeds with few emerged north of mid Iowa except in burned over areas and some gardens. The difference between that advance and this one is that the former involved butterflies returning from Mexico while this one involves first-generation offspring migrating north from Texas. Being young and still maturing, the first-generation migrants should be able to “wait” for the emergence of milkweeds in these northern areas.

Below are graphs of the temperature, wind speed and wind direction data from my weather station in Berryton, Kansas from 8 through 10 May. The pattern for the 8th was typical for this area and date. The records for the 9th and 10th show extremely gusty winds along with temperatures well above the long-term average.

The timing of the colonization of the northern breeding areas varies from year to year. There are both early and late years. Early years are of interest because they have the potential to give a jump start to the development of a large population. The most recent early year was 2018 which was followed by the largest overwintering population (6.05 hectares) since 2006 (6.87 hectares). However, being early can have negative consequences. The 2012 recolonization appears to have been too early, well in advance of the emergence of milkweeds and a recolonization that involved a number of partially reproductively spent monarchs that returned from Mexico rather than a cohort only of newly emerged first-generation monarchs with a substantial reproductive capacity. The overwintering count during the winter of 2012-2013 as only 1.19 hectares. (There were other factors that contributed to the low number at the end of 2012, but the early start was surely a factor).

So, how does the recolonization this year compare to that of 2018 and 2012? There are a couple of ways of summarizing the data on Journey North. First, we can just list all the sightings from 1 May through 15 May exclusive of sightings from west of the Rockies and east of 80W (western PA). Second, we can count only those sightings that occur N of 40N during that period.

Sightings from 1-15 May exclusive of western states and sightings east of 80W.

These are the three years in the record in which the area north of 40N has been colonized the earliest. In 2018, the population grew to 6.05 hectares from 2.48 the previous year while in 2012, it declined from 2.89 hectares to 1.19. Going back through all the years with first sightings, the pattern of the timing of colonization and growth in 2001, an increase from 2.83 hectares in 2000 to 9.35 hectares at the end of 2001, is similar to that of 2018. Given these precedents, it looks like the colonization of early May this year will lead to an increase in numbers through the summer, into the fall and will eventually result in an increase in numbers next winter. Still, it’s early, and we need to watch how the colonization progresses from now through the 14th of June. After that, we need to follow how the population develops during the summer, how the migration progresses in the fall and more. I’m hoping for a good year.

When monarchs are like corn

I received an email this past week (<1May) that referenced an article with an alarming headline. "US corn planting slowest since 2013, yield risks still premature". Why should this be alarming? Well, I’m going to tell you why and when monarchs are like corn. It’s been on my list to do so for some time. This headline gave me the motivation to start this discussion. Let's start with the obvious, corn doesn't fly, lay eggs, visit flowers or migrate, but it does grow and every farmer knows that yields are dependent on numerous factors and that two of the most important are timing of planting and temperatures. There's the similarity – timing and temperature. Do you remember the size of the monarch overwintering population in 2013? It was the lowest ever measured, a mere 0.67 hectares. The number was alarmingly low, a number so shocking that it led to an international agreement between the governments of Canada, the United States and Mexico and a White House invitation to stakeholders to a meeting at the Eisenhower Office Building in D. C. to discuss the issue. This meeting was followed by a Presidential Memorandum on the 20th of June 2014 asking 14 Federal Agencies to actively pursue actions that would benefit monarchs and pollinators. Later, five parties petitioned the Department of Interior to declare monarchs a threatened species. The sharp decline in monarch numbers in 2013 led to an abundance of research directed at trying to understand monarch biology as well as how best to address the loss of habitat which was seen as the major cause for the decline. For my part, I tried to focus on how monarch population growth was affected by seasonal conditions and wrote the following about the decline: Monarch population crash in 2013. Most of this text is still relevant though I know more about monarch population growth now than I did then. Here are the main reasons for the decline.

“The low number of monarchs reported at the overwintering sites in Mexico in the winter of 2013-2014 appears to have been the result of a series of negative weather events that began in the summer of 2011. Excessive temperatures and droughts in 2011 and 2012 followed by low initial colonizing numbers in the spring of 2013 account for the decline. More favorable conditions for population growth allowed the population to increase in 2014 and 2015.” In addition, the timing of the returning monarchs in 2013 was late, in fact, the latest in the record. Which brings me back to corn and timing and temperature.

Both corn and monarchs were affected negatively by these conditions. Corn yields in 2012 were the lowest since the early 90’s – estimated to be -22.2% below the long-term trend. And monarchs were the lowest measured (1.19 hectares) since the start of record keeping in 1994. Corn yields were also below the long-term average in 2013 and monarchs were, as mentioned, were even lower in the winter of 2013.

To get a sense about how the weather this spring compares with that of 2013, I looked up the the deviations from long term mean temperatures for March-May from Texas to Minnesota for both 2013 and 2022.

As you can see, the March temperatures in 2013 were substantially below normal except for Texas. April means were universally low. Though this spring is later than many in recent years, the mean temperatures for March were above average. April temperatures were lower and the first week of May has been colder than predicted from past means. If May temperatures continue to be cooler than normal, the northern movement of first-generation monarchs originating in Texas will be delayed and so will corn planting, resulting in a lower fall population for monarchs and a lower corn yield per acre. At the time of this writing (1 May), it seems likely that the overwintering number next winter will be higher than in 2013. However, the number will certainly be no more than 3 hectares and perhaps much lower.

Monarchs dipped and recovered from 2011-2015 and so did corn. The general pattern is similar. So, in the sense that both responded similarly to the physical conditions, monarchs are like corn and the converse. This response exists in spite of the fact that the areas represented in the measures of monarchs and corn are quite different. Most monarchs that reach the overwintering sites originate from the western part of the Midwest while corn production includes large areas with lower monarch recovery rates in Mexico. Corn recovered from the downturn faster than monarchs and that’s to be expected due to the manner of propagation. Corn starts with similar acreage each year whereas monarchs start with the number and timing of those returning from Mexico which can vary greatly from year to year.

The existence of data on both monarchs and corn that can be related to temperatures and weather extremes allows for these comparisons. Similar relationships surely exist for a large number of co-occurring plants and animals. Soybeans also declined from 2010 through 2012 yet increased again in 2013. However, the overall similarity between crop yields and monarch numbers is compromised in this case by the adoption of new varieties and better production methods through the years. The larger point here is that what happened to monarchs from 2010-2015 was not unique. It’s likely that a large number of species were similarly affected during this interval.

Addendum
As of 13 May, the warmer weather in the Midwest that began on the 8th has changed the outlook for both the corn growers and monarchs. Planting has intensified and the northward migration of first-generation monarchs has been aided in an extraordinary manner by strong winds from the south and southwest. Again, these improvements demonstrate that corn, monarchs and many other species respond in a similar manner to weather conditions.

Tag recovery list updated

More than 900 Monarch Watch tags were recovered from monarch overwintering sites in central Mexico during the 2021 tagging season. All of the tags have been examined and the “Tag recoveries from central Mexico” list has been updated. By default, this list is sorted by the report season then by tag code and now includes nearly 21,000 records.

To view the tag recovery lists, please visit monarchwatch.org/tagrecoveries

Thank you to everyone who tagged monarchs in 2021 and also those who assisted with the recovery efforts!

Monarch Watch Update April 2022

This newsletter was recently sent via email to those who subscribe to our email updates. If you would like to receive periodic email updates from Monarch Watch, please take a moment to complete and submit the short form at monarchwatch.org/subscribe/

Happy Earth Day, Monarch Watchers!

Included in this issue:
1. Monarch Watch Open House & Spring Plant Fundraiser
2. Follow Monarch Watch on LinkedIn
3. Monarch Population Status
4. Monarch Tag Recoveries from Mexico
5. Monarch Puzzle Wrap Up
6. Directional Flight
7. Free Milkweeds for Restoration Projects
8. About This Monarch Watch List

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1. Monarch Watch Open House & Spring Plant Fundraiser
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It’s here! Our annual Spring Plant Fundraiser is now online at https://spring.monarchwatch.org and we have thousands of plants looking for good homes. We are once again offering online ordering and contactless curbside pickup (or limited local delivery) for this event. To place an order you must live in, or be willing to travel to, LAWRENCE, KANSAS (we cannot ship). These plants are ideal for starting butterfly gardens or adding to established gardens and can contribute to the health of monarch and pollinator populations. Don’t miss out!

A complete list of plants and online ordering is available via the link below and pickup/delivery appointments are being scheduled for May 3-7.

Monarch Watch Spring Plant Fundraiser: https://spring.monarchwatch.org

We are also having an in-person component of our Spring Open House & Plant Fundraiser on Saturday, May 7th. This will be an outdoor-only event and there will be tours of our gardens, games, activities, monarch butterflies, caterpillars, and lots of butterfly plants available for your own garden! Complete details at https://monarchwatch.org/openhouse/

If you are not able to participate locally, we invite you to contribute to this annual fundraiser by donating to Monarch Watch via https://monarchwatch.org/donate

Thank you!

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2. Follow Monarch Watch on LinkedIn
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Monarch Watch has established a presence on LinkedIn so if you’d like make a connection and follow us on that platform, head on over to our new page at https://linkedin.com/company/monarchwatch and hit that Follow button!

See you there 🙂

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3. Monarch Population Status —by Chip Taylor
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I have looked at a lot of monarch and weather data over the years in attempts to understand the factors that influence the development of the population. These factors include the number of monarchs returning to Texas from Mexico, whether the migration is early or late, the mean temperatures in March, the timing of the emergence of milkweeds, the abundance of nectar sources and the temporal and spatial distribution of egg laying by returning females. Additional weather-related factors include soil moisture and rainfall.

That’s a lot to track and it gets confusing when trying to sort through the data over decades since the impact of some factors is affected by others. For example, droughts have a greater impact when temperatures are high than when they are low. While it will take months to sort out how the population develops this year, I’ve put together some distribution maps of monarchs and milkweeds based on photos submitted to iNaturalist to see how the conditions this year compare to those in 2021. As you will see, the numbers this year do not compare well with last year. The numbers of returning monarchs were lower this past March and the numbers of photos of milkweeds were also lower. Monarchs seem to be well ahead of emerging milkweed.

Overall, the population doesn’t appear to be off to a good start. However, the numbers could be somewhat misleading. Last year, we had a special project with iNaturalist based on an attempt to determine how severely the massive freeze in Texas in February 2021 affected monarchs and nectar sources. It’s possible that our appeal for help last year generated an unusual number of submissions. Still, as I write (6 April), the first monarch has been reported in southern Kansas well ahead of the milkweeds.

Here are links to the reports generated through the collaboration with iNaturalist last year:

Monarchs and the freeze in Texas
https://monarchwatch.org/blog/2021/06/01/monarchs-and-the-freeze-in-texas/

Nectar plants used by monarchs during March in Texas
https://monarchwatch.org/blog/2021/05/25/nectar-plants-used-by-monarchs-during-march-in-texas/

And if you are interested in the distribution Maps I mentioned above, please see
https://monarchwatch.org/blog/2022/04/22/monarch-population-status-47/

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4. Monarch Tag Recoveries from Mexico
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We are in the process of vetting the tag recoveries from the overwintering sites in Mexico (about 900 of them in total) and we will post the complete list online very soon so stay tuned!

Monarch Watch tag recoveries: https://monarchwatch.org/tagrecoveries

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5. Monarch Puzzle Wrap Up —by Chip Taylor
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I want to thank all of you who participated in the puzzle. I challenged you to come up with the same possible explanation I did for why first-generation monarchs appear to stop directional flight on specific dates in June at different latitudes (cities). I had been thinking about the question for decades and it took me a long time to come up with the answer. I did so the hard way by looking at how a lot of variables changed with the change in the seasons. The answer ultimately was so simple that I couldn’t believe that I hadn’t thought of it. Many of you had difficulties as well. It comes down to conceptualizing what happens to day length in both the spring and early summer and later in the season from late summer through fall. I didn’t ask you to think about the symmetry of the seasonal changes, but it probably would have helped.

There were 22 submissions to the puzzle contest. I had intended to award the Mariposas board game to the first three participants with the correct answer or something close to it. It turned out that the puzzle was harder than I suspected and we had to go through three rounds in which I tried to leave word crumbs that participants could follow with each iteration. I finally had to admit that it’s difficult to conceptualize an increasing function that is progressively decreasing even though those are the seasonal conditions we live with twice a year and that many of us learned as children. So, for those who kept trying, and especially for those who seemed to be on the right track, I coached them by adding a few more word crumbs they could follow. Ultimately, I ended up awarding the Mariposas board game to 5 participants. One of the interesting things for me was the number of times when dealing with the answers I had to go back to suncalc.org to make some more calculations. The puzzle was a learning process for me as well as for many of the participants. From my standpoint, that’s a good outcome.

For a more complete discussion and puzzle wrap up please see
https://monarchwatch.org/blog/2022/04/22/monarch-puzzle-wrap-up/

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6. Directional Flight —by Chip Taylor
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As a follow-up to the puzzle challenge, the next steps involve teaching citizen scientists how to distinguish directional flight from meandering behavior. It’s distinctive, and once learned by volunteers, we can ask “flight spotters” to record whether they are seeing directional flight through May and June. We now have a hypothesis to test based on dates and latitudes. So, for any one site all an observer would have to do is record whether directional flight was observed (weather permitting) over the short period involved. I have already lined up one team in Michigan who will be making these observations. They will also be recording data from the nearest “Tempest” weather station in an effort to closely associate their observations with the behavior of the monarchs. Having a good location where the passing monarchs can be highlighted against the sky will be key. A compass will be needed as well.

I should mention that the shut down of directional flight might not be as abrupt as suggested in the puzzle. Rather, there might be a decline in directional flight over several days rather than an abrupt cutoff. Since we would be looking for a behavior that is declining with fewer individuals showing directional flight each day, it may be difficult to identify the exact date when directional flight ceases at each location.

Oh, almost forgot. There is one more thing that makes me believe that this line of research is worth pursuing – the converse.

What is the rate of change from one day to the next when the monarchs first arrive at the overwintering sites in Mexico at the end of October? Again, the rate of change drops below 1 minute – ranging from -58 to -56 seconds from 29 Oct to 2 Nov at Angangueo. In this case, in contrast to stopping directional flight, the migration toward the overwintering sites continues southward through Mexico until sometime in early December when the change per day is about -20 seconds. That gives us another mystery, doesn’t it? Why would monarchs experiencing increasing daylength that is increasing at a decreasing rate stop directional flight while monarchs that are experiencing decreasing daylength that is decreasing at a decreasing rate keep flying? Every aspect of monarch biology seems to be complicated, doesn’t it?

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7. Free Milkweeds for Restoration Projects
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We are in need of CALIFORNIA applicants!

The Free Milkweeds for Habitat Restoration program focuses on distributing free milkweed plugs for large-scale habitat restoration projects throughout the range of the western monarch butterfly population in California and the eastern population east of the Rocky Mountains. The focus is on the main migration routes.

In California we currently have milkweed seed ecotypes for the Central Valley and Southern California. Only projects in these areas will be eligible for free milkweeds this spring. Projects must be a minimum of one acre.

More info and to apply: https://monarchwatch.org/free-milkweed-restoration

For projects east of the Rockies, the application is still open and there are a few milkweeds still available for 2+ acre projects.

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8. About This Monarch Watch List
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Monarch Watch ( https://monarchwatch.org ) is a nonprofit education, conservation, and research program affiliated with the Kansas Biological Survey & Center for Ecological Research at the University of Kansas. The program strives to provide the public with information about the biology of monarch butterflies, their spectacular migration, and how to use monarchs to further science education in primary and secondary schools. Monarch Watch engages in research on monarch migration biology and monarch population dynamics to better understand how to conserve the monarch migration and also promotes the protection of monarch habitats throughout North America.

We rely on private contributions to support the program and we need your help! Please consider making a tax-deductible donation. Complete details are available at https://monarchwatch.org/donate or you can simply call 785-832-7374 (KU Endowment Association) for more information about giving to Monarch Watch.

If you have any questions about this email or any of our programs, please feel free to contact us anytime.

Thank you for your continued interest and support!

Jim Lovett
Monarch Watch
https://monarchwatch.org

You are receiving this mail because you were subscribed to the Monarch Watch list via monarchwatch.org or shop.monarchwatch.org – if you would rather not receive these periodic email updates from Monarch Watch (or would like to remove an old email address) you may UNSUBSCRIBE via https://monarchwatch.org/unsubscribe

If you would like to receive periodic email updates from Monarch Watch, you may SUBSCRIBE via https://monarchwatch.org/subscribe

This e-mail may be reproduced, printed, or otherwise redistributed as long as it is provided in full and without any modification. Requests to do otherwise must be approved in writing by Monarch Watch.

Monarch Puzzle Wrap Up

I want to thank all of you who participated in the puzzle. I challenged you to come up with the same possible explanation I did for why first-generation monarchs appear to stop directional flight on specific dates in June at different latitudes (cities). I had been thinking about the question for decades and it took me a long time to come up with the answer. I did so the hard way by looking at how a lot of variables changed with the change in the seasons. The answer ultimately was so simple that I couldn’t believe that I hadn’t thought of it. Many of you had difficulties as well. It comes down to conceptualizing what happens to day length in both the spring and early summer and later in the season from late summer through fall. I didn’t ask you to think about the symmetry of the seasonal changes, but it probably would have helped.

So, what does happen to day length through the seasons? We all know that day length increases in the spring, but it is easy to forget that it increases at a decreasing rate. The same, but different, change occurs after the summer solstice (21 June). In this case, the day length decreases, but again, at a decreasing rate.

As you may recall from how the puzzle was framed, I started with a single observation, namely that first generation monarchs “appeared” to stop directional flight in our area sometime after the 5th of June. Then I asked what was the difference between all the variables from one day to the next and then the next. Again, since I knew that the migration stopped sometime in early June at all latitudes, I asked if the rate of change seen from the 5th to the 6th of June followed a similar pattern with increasing latitudes. I chose Ames, St Paul and Winnipeg to see if the pattern matched. I chose the probable day before the migration stopped at each city based on the distance from Lawrence. Then I used suncalc.org to calculate the increase in day length from one day to the next. Eureka! There is a three-day match for the four sites with the rate of increase being similar from one day to the next. When I worked back through earlier dates, I realized that the results represented a point in time for each location at which the rate of change dropped below one minute per day. Specifically, I noted that the difference between the hypothetical last day of flight and the proposed stop day ranged from 50-55 seconds. That was my “Eureka” moment. What those data suggested to me was that the rate of change had become so small from one day to the next that the change could no longer be detected by the monarchs and they stopped directional flight. In other words, it was a loss of signal issue such that without a detectable rate of change per day the monarchs simply stopped migratory flight. That ultimately might not be the correct explanation, but it constitutes a working hypothesis to be tested. I will get into next steps below, but one of the things that happened by raising the issue of stopping directional flight was learning from Carol Clark that monarchs appeared to stop directional flight in the Dallas area in the first days of June. That led me to run the numbers for Dallas starting with 31 May. Bingo! Another match. That’s confirmation of the pattern – a good first step in testing the hypothesis.

There were 22 submissions to the puzzle contest. I had intended to award the Mariposas board game to the first three participants with the correct answer or sometime close to it. It turned out that the puzzle was harder than I suspected and we had to go through three rounds in which I tried to leave word crumbs that participants could follow with each iteration. I finally had to admit that it’s difficult to conceptualize an increasing function that is progressively decreasing even though those are the seasonal conditions we live with twice a year and that many of us learned as children. So, for those who kept trying, and especially for those who seemed to be on the right track, I coached them by adding a few more word crumbs they could follow. Ultimately, I ended up awarding the Mariposas board game to 5 participants. One of the interesting things for me was the number of times when dealing with the answers I had to go back to suncalc.org to make some more calculations. The puzzle was a learning process for me as well as for many of the participants. From my standpoint, that’s a good outcome.

There are three puzzle submissions I have to tell you about, one by Chris Mentrek who created a graphic solution, one by Cammie Machholz who concentrated on sunrise and sunset data and one by Jill Larson who discovered a website that does all the work for you.

To quote from Jill’s email – “I found a better website to use, and you don’t need to calculate! Of course, discovered after I used paper and pen. Try out timeanddate.com. There is a drop down for Sun & Moon, and you enter the location. Then you can see whole months at a time with the difference in duration of daylight listed in the chart. Pretty neat.” This discovery demonstrates that I do things the hard way and asked you to do the same. Sorry about that. No wonder this was difficult. I should mention that the readout for each day at this site shows the time of sunrise and sunset as well as the sun angle at solar noon (SASN).

To show the change from the hypothetical last day of directional flight to the next two days for each location, I have combined screen shots for Lawrence, Ames, St Paul and Winnipeg from the time and date site. There are 1 second differences between the data from this site and suncalc.org.

(For those of you who are curious about how daylength changes through the entire year, enter your location and then track the rates of increase and decrease from December to December. When starting on the 21st of Dec you will notice a slow increase in daylength which will increase and then the positive rate of change will slow as the 20 March equinox is approached. After the 20th of March, daylength keeps increasing but the rate of increase declines to 0 on the 21st of June).

Cammie Machholz focused on the change in the rate of increase in sunset and sunrise. She concluded that the similarities of the differences in sunrise and sunset across the latitudes could be why monarchs stopped directional flight. Indeed, these are components of the 50-55 second increase and show the same pattern as the total increase.

Sunrise
Dallas – May 31 to June 1 – 17 seconds earlier
Lawrence – June 5 to June 6 – 15 seconds earlier
Ames – June 7 to June 8 – 15 seconds earlier
St. Paul – June 8 to June 9 – 16 seconds earlier
Winnipeg – June 11 to June 12 – 14 seconds earlier

Sunset
Dallas – May 31 to June 1 – 35 seconds later
Lawrence – June 5 to June 6 – 36 seconds later
Ames – June 7 to June 8 – 37 seconds later
St. Paul – June 8 to June 9 – 37 seconds later
Winnipeg – June 11 to June 12 – 36 seconds later

Cammie’s data suggests another hypothesis namely that the cue could involve a change perceived or not perceived on the horizon, possibly at the end of the day. There are other possible hypotheses, but we have a good place to start.

Below are Chris Mentrek’s graphical solutions. His graphs nicely show the convergence of dates and locations and easily beat my summary. Chris’s answer was more than I expected from any participant. Other winners simply showed the similarities among sites in the rate of change from one day to the next.

The migration-halt dates for the four cities in question DO follow a nicely-predictable pattern:

Here’s something that’s similar for these cities on the dates in question: the amount of change in daylight.

However, unless the butterflies are carrying this chart in their heads (along with an ability to sense latitude and the date), there’s probably a more-indirect clue in their environment that conditions are right to stop migrating north.

Every day in the spring, a site’s minutes-of-daylight will increase until the summer solstice — June 21st. In May and June, each day gets longer by slightly-less time than the day before. This change in the daylight length varies a lot with both date and latitude. (For example, Winnipeg sees a drop from 167 seconds-per-day to 0 from May 15th to June 21st.)

It’s not a perfect prediction, but the migration-stop dates all seem to occur when a site’s change in daylight reaches about 53 seconds. (For example, Winnipeg’s daylength drops from 55 to 50 seconds on the migration-stop date, while Lawrence’s daylength drops from 54 to 50 seconds.)

To sense this, the butterflies only need to be able to sense how much daylight they’re experiencing, and how it changes day by day. It might be a handy way to infer their latitude!

Directional Flight

As a follow-up to the puzzle challenge, the next steps involve teaching citizen scientists how to distinguish directional flight from meandering behavior. It’s distinctive, and once learned by volunteers, we can ask “flight spotters” to record whether they are seeing directional flight through May and June. We now have a hypothesis to test based on dates and latitudes. So, for any one site all an observer would have to do is record whether directional flight was observed (weather permitting) over the short period involved. I have already lined up one team in Michigan who will be making these observations. They will also be recording data from the nearest “Tempest” weather station in an effort to closely associate their observations with the behavior of the monarchs. Having a good location where the passing monarchs can be highlighted against the sky will be key. A compass will be needed as well.

I should mention that the shut down of directional flight might not be as abrupt as suggested in the puzzle. Rather, there might be a decline in directional flight over several days rather than an abrupt cutoff. Since we would be looking for a behavior that is declining with fewer individuals showing directional flight each day, it may be difficult to identify the exact date when directional flight ceases at each location.

Oh, almost forgot. There is one more thing that makes me believe that this line of research is worth pursuing – the converse.

What is the rate of change from one day to the next when the monarchs first arrive at the overwintering sites in Mexico at the end of October? Again, the rate of change drops below 1 minute – ranging from -58 to -56 seconds from 29 Oct to 2 Nov at Angangueo. In this case, in contrast to stopping directional flight, the migration toward the overwintering sites continues southward through Mexico until sometime in early December when the change per day is about -20 seconds. That gives us another mystery, doesn’t it? Why would monarchs experiencing increasing daylength that is increasing at a decreasing rate stop directional flight while monarchs that are experiencing decreasing daylength that is decreasing at a decreasing rate keep flying? Every aspect of monarch biology seems to be complicated, doesn’t it?

Monarch Population Status

I have looked at a lot of monarch and weather data over the years in attempts to understand the factors that influence the development of the population. These factors include the number of monarchs returning to Texas from Mexico, whether the migration is early or late, the mean temperatures in March, the timing of the emergence of milkweeds, the abundance of nectar sources and the temporal and spatial distribution of egg laying by returning females. Additional weather-related factors include soil moisture and rainfall.

That’s a lot to track and it gets confusing when trying to sort through the data over decades since the impact of some factors is affected by others. For example, droughts have a greater impact when temperatures are high than when they are low. While it will take months to sort out how the population develops this year, I’ve put together some distribution maps of monarchs and milkweeds based on photos submitted to iNaturalist to see how the conditions this year compare to those in 2021. As you will see, the numbers this year do not compare well with last year. The numbers of returning monarchs were lower this past March and the numbers of photos of milkweeds were also lower. Monarchs seem to be well ahead of emerging milkweed.

Overall, the population doesn’t appear to be off to a good start. However, the numbers could be somewhat misleading. Last year, we had a special project with iNaturalist based on an attempt to determine how severely the massive freeze in Texas in February 2021 affected monarchs and nectar sources. It’s possible that our appeal for help last year generated an unusual number of submissions. Still, as I write (6 April), the first monarch has been reported in southern Kansas well ahead of the milkweeds.

Here are links to the reports generated through the collaboration with iNaturalist last year:

Monarchs and the freeze in Texas
https://monarchwatch.org/blog/2021/06/01/monarchs-and-the-freeze-in-texas/

Nectar plants used by monarchs during March in Texas
https://monarchwatch.org/blog/2021/05/25/nectar-plants-used-by-monarchs-during-march-in-texas/

Monarch – Danaus plexippus – 2022 N=392 (below left) and 2021 N=534 (below right)

Antelopehorn – Asclepias asperula – 2022 N=34 (below left) and 2021 N=207 (below right)

Green antelopehorn – Asclepias viridis – 2022 N=6 (below left) and 2021 N=45 (below right)

Zizotes – Asclepias oenotheroides – 2022 N=24 (below left) and 2021 N=68 (below right)

Monarchs, milkweeds and O. e.: It’s time for a more holistic approach

There have been many papers written on the relationship between monarchs and their neogregarine parasite Ophryocystis elektroscirrha, hereafter referred to as O.e. These papers have covered a number of topics including, infection rates, how spores are distributed by infected adults, how the relative attractiveness and overwintering persistence of tropical milkweed appears to contribute to the frequency of O.e., the relationship of sublethal infections on the fitness of monarchs, especially as it determines the ability to migrate, and frequency as it relates to continuous breeding and geographic distributions and others. These studies constitute a useful baseline or foundation for further studies. In this short article, I’m going to argue that to fully understand the relationship between monarchs and O.e. we need a more comprehensive approach, one that accounts for the seasonal and geographic dynamics of the monarch population, the density and frequency dependent interactions in the system, the impacts of other predators and parasites and the effects of weather on the outcomes. While I’m advocating a holistic approach, I’m not attacking the research conducted to date nor am I claiming to have the answers. However, I do feel that a broader understanding of the complexities of the interactions in monarchs’ annual cycle and its interactions with all components in the system will be helpful. There are some obvious relationships that are begging for data.

O.e. has a unique life-history that involves ingestion of spores by larvae but ends with masses of spores on the outside of the adult host. Here is the short version of that process. To become infected, a monarch larva consumes the chorion (egg shell) along with O.e. spores shed on the egg or the surrounding leaf surface during oviposition. A larva can also eat spores deposited on milkweed leaves by infected or contaminated monarchs that have landed on the leaves. The spores consumed by the caterpillar “germinate” in its alkaline gut and a malaria-like stage of O.e. (sporozoite) migrates through the gut wall to the tissues (hypoderm) beneath the caterpillar’s skin. This stage is followed by vegetative reproduction and then a period of quiescence. Late in the pupal stage, variously said to be the 8th day of pupation or three days before emergence, O.e. goes through a process of reproduction that results in a massive production of spores (sporulation) just beneath the cuticle of the pupa and on the outside of the developing monarch. Upon emergence, the adult monarch can carry extremely large numbers of spores, especially on the abdomen. The dust-like spores are lost progressively through the life of an infected adult monarch. O.e frequency is usually determined from sticky taped samples of scales taken from a monarch’s abdomen. Upon inspection with a microscope, high numbers (thousands) of spores indicate infection, low numbers (a hundred or less) indicate contamination through contact with other monarchs or contaminated surfaces. In the wild, an unknown portion of O.e. infected larvae, pupae and adults with crumpled wings die before they are able to take flight to reproduce or migrate, and therefore are not included in the sampling to determine the frequency of O.e. Thus, it’s likely that the mortality and morbidity due to O.e. is greater than measured. This mortality can be seen in badly infected monarch cultures, but we have no idea how common it is in the wild.

I’m going to start with migratory culling and how that relates to the carryover of O.e. spores from one year to the next. While it’s clear that a significant proportion of the infected monarchs are eliminated during the migration due to reduced life span and flight capability, there is no data indicating that infected monarchs return in the spring to establish the O.e. infection rate. If we assume that the culling eliminates nearly all of the highly infected individuals either during the migration, through the winter or during the migration from the overwintering sites to Texas, that means that O.e predominantly starts the next year as incidental spores carried on non-infected individuals (also referred to as contaminated or spore infested) through horizontal transfer due to contact with other individuals or contaminated surfaces. The proportion of returning monarchs that are contaminated with O.e. spores as they reach Texas is unknown. That proportion and how it varies from year to year is critical to our understanding of how O.e. increases each year. On the other hand, if a substantial number of infected females survive the migrations and reach Texas in the spring, the distribution of spores on the eggs they lay, and the milkweeds they contact, would result in a more efficient way to establish O.e.

The next consideration is how those spores are distributed on milkweeds as these returning monarchs move northward. The returning monarchs carrying spores advance at a rate of 30-55miles per day with some mating and with females laying eggs as they move northward. As this population progresses, the spores are dispersed on the milkweed foliage through egg laying and other foliage due to nectaring and resting. In effect, there is a trail of spores which thins out with increasing latitude to the point at the northern limit reached by overwintered monarchs where there are almost no spores to be ingested by monarch larvae. In other words, the loss of spores fits a decay function, i.e., a frequency of spores that declines with distance. In this scenario, relatively few of the first-generation monarch larvae will ingest spores and most of those larvae that do so will originate from the most southern range with milkweeds. However, we need to consider “egg dumping”. This term refers to the tendency of female monarchs, either the same female, or multiple females, to lay multiple eggs on relatively scarce new milkweed shoots. This concentration of egg laying and multiple touches by contaminated females is likely to have the effect of increasing the numbers of infected first-generation adults. Since egg dumping is usually reported only when milkweed shoots, or even mature plants, are scarce, this dynamic illustrates one of the frequency/density relationships in the system. If the abundance of O.e. contaminated females is high relative to the number of available shoots or mature plants, that favors multiple touches and multiple deposits of spores (frequency) along with eggs on relatively small numbers (density) of plants. That will certainly lead to an increase in O.e. What we don’t know is how much egg dumping occurs, how it differs regionally and from year to year. It seems likely that since we know that milkweeds are less abundant in some regions, such as the SE, that egg dumping is more common in that region. On the other hand, there is variation in the phenology of both milkweed growth and monarch occurrence such that, in some years, if milkweeds have emerged in abundance before the arrival of monarchs, the dumping will be less common resulting in lower rates of infection than in years when shoots are scarce. These dynamics could result in significantly different proportions of infected first-generation monarchs moving north from different regions as well as in different years. As monarchs continue to move north in May and early June, egg dumping is less of a factor since milkweeds have typically emerged and are abundant N of 40N at this time.

First generation monarchs begin moving N in the last week of April and they too, as a population, will leave a trail of spores which will also decline due to distance. It follows that relatively few of the monarchs reaching the latitudes N of 40N, but especially above 45N, will carry spores to the most northern and eastern latitudes and longitudes. Given what is known of migratory culling, it is likely that most of the spore-carrying first generation monarchs moving north will be either lightly infected or simply contaminated with spores through horizontal transfer.

How the O.e. numbers build up after the recolonization has occurred will depend on a number of factors starting with the number of recolonizing monarchs and the proportion carrying spore loads. Beyond that, we have to be concerned about the abundance and spatial distribution of milkweeds. These considerations take us back to the density and frequency-dependent relationships that determine the infection rate for the next generation. If there are low numbers of infected and contaminated individuals and milkweeds are exceedingly abundant relative to the monarch numbers, the infection rate for the next generation might increase slightly but will still be low. On the other hand, if the numbers of infected and contaminated females are high relative to the abundance of milkweeds, the frequency of O. e. will increase significantly. In highly fragmented environments where the distances between patches are substantial, there will be hot spots where the incidence of O.e. will be quite high if infected and contaminated females continue to return to the same plants for oviposition. Since there are few regions with an even distribution of milkweeds, it is likely that a fine-grained approach to sampling will find that Oe varies within regions as a function of monarch abundance as well as the spatial distribution and abundance of milkweeds.

The escape hypothesis, which posits that monarchs disperse to escape high frequency infection rates by O.e., doesn’t really fit with the monarchs’ seasonal migrations. In the spring, monarchs returning from Mexico simply migrate – distributing eggs (progeny) as the migration advances. They are not escaping a high incidence of O.e. That can also be said of the first- generation monarchs that migrate north from late April to early June. These monarchs are advancing into areas where milkweed is more abundant and where temperature and moisture conditions are more favorable for reproduction. If anything, monarchs are abandoning the southern latitudes due to the tendency for two of the more common milkweeds to senesce during the summer months and for high temperatures to be less favorable for reproduction. Further, once the migration stops at each latitude in June, monarchs disperse locally in search of milkweeds. Thereafter, the buildup of O. e. is a function of the size of the next generation, number of generations, abundance and distribution of milkweeds, interactions with predators and parasites that eliminate infected larvae and the weather. In effect, once the migration has stopped, the monarchs are stuck in one place irrespective of the buildup of O.e. or predators and parasites. One could argue that, if selection had favored escape from O.e., that the first-generation monarchs would not stop migrating across the latitudes through May and early June (See the puzzle solution –). The escape hypothesis seems to suggest that monarchs are aware of the O.e. infection rate or the buildup of predators and parasites. Cognition in insects? No, I don’t think so. It seems far more likely that dispersal and migration by monarchs is a selective response to changes in habitat quality.

In terms of the seasonal breeding dynamic, there is very little continuous reproduction south of 35N from late May until August. That’s related to the fact that, in much of the south, milkweeds senesce during the summer, and it is simply too hot for sustained reproduction. From that perspective, monarchs have been selected to vacate degrading habitats. That said, there are some exceptions where reproduction is continuous in coastal cities with lots of planted milkweed such as Houston and New Orleans. Based on that observation, and on the behavior of monarchs in areas such as southern Florida where reproduction is continuous, it seems that monarchs respond to the availability of resources rather than O.e., as well as other parasites and predators that are also common in those areas. O.e. infection rates are known to be high in these areas yet there appears to be no “escape”.

There is also the mid-summer migration in which monarchs move south of 40N to recolonize the southern latitudes from late July through the first three weeks of August. Some are probably carrying spores S from the northern latitudes. These monarchs are not “escaping” from areas with high frequencies of O.e. any more than the first gen monarchs are as they move N.

Because we can test for it, and determine its frequency, O. e. inspires concerns about the degree to which this parasite depresses the monarch population. Similar concerns have been voiced about the impact of introduced fire and crazy ants, ladybird beetles, European paper wasps and tachinid flies on monarch numbers. And then there are the periodic increases of resident parasites and predators that also take a toll. All of these species surely have an impact on monarch numbers, but to put these losses into context, we have to know where and when in the season these impacts occur. And in the case of monarchs that migrate, we have to know whether monarchs from all reaches of the eastern population have equal or strongly different probabilities of overwintering in Mexico and contributing to the population the following spring.

Lastly, O.e. appears to be a “self-limiting” disease/infection/organism. That is, a species that is capable of reducing the population of a host to a relatively low level from which, in time, the population will recover. In other words, monarchs and O.e. will cycle because of the spatial and temporal complexity of the environment. That complexity is related to the seasonal and spatial distribution of milkweeds and the presence of other species and weather conditions. There are a large number of parasites and predators that prey on monarch eggs, larvae and pupae such that the percentages reaching the adult stage are estimated to be 1-3%. As these species prey on monarchs, they also eliminate O.e. infected immatures. In some cases, the mortality rate due to these species approaches 100%. By eliminating adult monarchs and therefore reducing the distribution of spores to milkweed leaves and giving time for the O.e. spores that are present to degrade, portions of the larger range become monarch and O.e. free, allowing recovery when these locations are found by females that don’t carry spores. These actions create the complexity and escape in space monarchs need to recover from high levels of infection that reduce the population in other locations. Again, in these cases, the “escape” is simply an artifact of the constant dispersal conducted by monarch females in search of host plants. Fundamentally, there is nothing unique here since this dynamic is common to a large number of interactions between hosts and the species that prey on them. These dynamics are similar to those illustrated by a series of predator/prey and parasite/prey experiments conducted in greenhouses decades ago. In those experiments, predators or parasites could eliminate a host and themselves in the simplest of habitats. Complexity often produced cycles of hosts and parasites since the diversity/complexity of the habitats afforded escape by the hosts in time and space. Most greenhouse managers are well aware of the complexities involved in trying to control greenhouse pests with predators or parasites. Success is often temporary due to the ability of the prey (pest) species to escape in time and space.

Many of the hypothetical deductive scenarios I have outlined can be tested experimentally or, in some cases, through sampling that follows rigid protocols.

Conclusions

To understand the relationship between O.e., monarchs, milkweeds, predators, parasites and weather, we have to lay a foundation for the annual cycle of both monarchs and O.e as well as the seasonal, local and regional dynamics of the other species that interact with monarchs in a manner that modifies the O.e. frequency. In addition, we need to understand the density and frequency dependent interactions between monarchs, milkweeds and O.e. At present, our understanding of passive/horizontal transfer of O.e. spores is limited, and knowledge of the conditions, such as UV and high temperatures, that result in the degradation of O.e. spores is lacking. These conditions could explain the relatively low incidence of O. e. in Arizona in spite of the relatively low and highly fragmented distribution of milkweeds in much of that state.

Looking forward, in coming years, the continuing loss of grasslands, along with land conversion associated with development, will result in a loss of milkweeds, an increase in fragmentation and an increase in O.e. It should be noted that the recent increase in O. e. followed the adoption of herbicide tolerant crop lines in the early 2000s and the later adoption of the renewable fuel standard in late 2007 both of which resulted massive losses of milkweeds. These losses and the resulting increase in fragmentation could well account for the increase in O.e since the early 2000s. References to habitat losses due to these factors can be found in previous posts to this Blog.

Recent publications

Majewska, A. A., Davis,A. K., Altizer, S. and Jacobus C. de Roode. 2022. Parasite dynamics in North American monarchs predicted by host density and seasonal migratory culling. Journal of Animal Ecology.

Dargent, F., Gilmour, S. M., Brown, E. M., Kassen, R., and Heather M. Kharouba. 2021. Low prevalence of the parasite Ophryocystis elektroscirrha at the range edge of the eastern North American monarch (Danaus plexippus) butterfly population. Can. J. Zool. 99: 409–413.

Monarch Watch Update February 2022

This newsletter was recently sent via email to those who subscribe to our email updates. If you would like to receive periodic email updates from Monarch Watch, please take a moment to complete and submit the short Google Form at monarchwatch.org/subscribe/

Greetings Monarch Watchers!

This is a relatively brief update, primarily serving as a follow-up to some items in last month’s email. Thank you for your continued interest and support!

Included in this issue:
1. Monarch Watch One Day Fundraising Event
2. Monarch Watch Tag Recoveries
3. Free Milkweed Programs
4. A Return to the Monarch Puzzle
5. About This Monarch Watch List

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1. Monarch Watch One Day Fundraising Event
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As promised last month, below is the official announcement of this year’s one day fundraising event taking place next week. We will send out a reminder on the day of the event to give you easy access to the link, should you like to participate. Help us continue our mission to restore habitats for monarchs and native pollinators – donations of any amount do help and are greatly appreciated.

On Thursday, February 17th Monarch Watch will again be featured in the University of Kansas’ annual “One Day. One KU.” 24-hour fundraising campaign. This event provides an opportunity for Monarch Watchers all over the globe to come together and show their support of our programs.

This year you will be able to take advantage of FOUR matching opportunities to increase the impact of your gift:

1. Monarch Watch Director Chip Taylor and his wife, Toni, are matching dollar-for-dollar all gifts up to $4,000.

2. Dedicated supporter, Janet Lanza, will match dollar-for-dollar all gifts to Monarch Watch, up to $5,000!

3. KU alumna and Monarch Watch supporter, Susan Lordi Marker, will match dollar-for-dollar all gifts, up to $5,000!

4. An anonymous donor will match dollar-for-dollar all gifts up to $5,000 to Monarch Watch and encourages others to donate.

Additionally, many employers will match employee gifts to Monarch Watch so that is yet another opportunity!

To make a donation online the day of the event, visit https://kansas.scalefunder.com/amb/monarch

To make a gift by phone anytime between now and the day of the event, call KU Endowment at (888) 653-6111 – just be sure to mention that you would like to give in support of Monarch Watch for the one-day event.

Don’t forget to check your email on February 17th for the reminder and link – thank you!

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2. Monarch Watch Tag Recoveries
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Many of you have been asking about when tag recoveries for the 2021 tagging season will be posted online.

Recoveries from the overwintering sites in central Mexico are typically reported to us in February/March and posted online in March/April once everything is received and verified. We will make an announcement via our email updates so stay tuned!

The tag recoveries within the U.S., Canada and northern Mexico are typically posted in January/February once everything has been vetted – a link to the list is now posted online at https://monarchwatch.org/tagrecoveries

As a reminder, if you have not submitted your tagging data to us yet, it is not too late! Complete information (including links to the tag data submission form and recovery lists) is available on our Monarch Tagging Program page at https://monarchwatch.org/tagging

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3. Free Milkweed Programs
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For habitat restoration projects

Monarch Watch will once again be distributing free milkweeds for planting in large-scale habitat restoration projects for Spring 2022. Since this program began in 2015, almost 252,000 milkweeds [edit: more than 650,000 milkweeds] have been planted in restored habitat throughout much of the range of the eastern monarch population.

New this year, we will be able to distribute free milkweeds to many areas of California (in addition to areas east of the Rocky Mountains) – please see the link below for complete details. To qualify, applicants must have a minimum of two acres (one acre in CA) to restore to natural, native habitat, and have a management plan in place. Milkweeds are awarded on a first come, first served basis, so apply early.

Those awarded free milkweeds need only pay shipping/handling, which is modest compared to the value of the plants. Please help us spread the word by sharing widely. For more information and to apply, please visit:

https://monarchwatch.org/free-milkweed-restoration

For Schools and Nonprofits

The Free Milkweeds for Schools and Nonprofits Grant is in its 8th year and we are still distributing free milkweeds to those who qualify. Through the generous support of the Natural Resources Defense Council, this program provides funding for 6000 plants. Each recipient receives one full flat of milkweed plants to be added to a public garden. Schools, libraries, nature centers and museums are examples of past recipients. This program is available to applicants in California and all states east of the Rocky Mountains. The application can be found here:

https://monarchwatch.org/free-milkweed-schools-nonprofits

Sorry, this program is not intended for private yards or free milkweed giveaways.

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4. A Monarch Puzzle – Chip Taylor
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The contest is still on.

“When does the migration northward end – or does it”?

In a monthly update posted in June of 2003 with the above title, I wrote “My guess is that the migration stops at each degree of latitude northward at a particular date, that these dates can be predicted, and that all directional migration stops before the 21st of June at all latitudes.” Over the years I have returned to that question several times and have asked myself repeatedly what might the monarchs be responding to that would stop directional flight. The question is basically – what is changing and how is that change perceived by the monarchs? Further, whatever the cue is, it has to be similar over all latitudes.

So, what could it be? I think I’ve figured it out, and I think you can too. That was the basis for the puzzle in the last email update (see original text below). The challenge was to identify a factor common to all locations that could explain why monarchs would stop directional flight on a certain date.

Fourteen people submitted answers to the puzzle by the end of January. None of them arrived at the answer I was seeking and that’s not surprising. It’s a difficult question, and it took me a long time to arrive at the pattern that I think explains when monarchs stop directional flight in late May to early June from Dallas to Winnipeg.

All of the respondents mentioned seasonal changes, and these ranged from temperatures and winds to changes in vegetation, daylength and sun angle. However, none of them pointed to a specific change that was common to all four sites – specifically a change that the monarchs might respond to.

I’m confident that many of you can get to the answer I did, and to get you there, I’m are going review a few things and direct you to a website. (In the original puzzle, the dates for St. Paul and Winnipeg were incorrect, being 9 and 12 respectively. They are corrected in the table below).

Table 1. Seasonal metrics for specific locations.

It’s clear from this table that daylength, sun angle at solar noon and at the solstice (21 June) all change with date and latitude. So, none of these changes per se can explain why monarchs might stop migrating on the dates suggested. Yet, there is change. So, the question becomes is there a feature of the changes that are occurring that is common to all locations? There are a number of sources on the internet that are useful in this context. My favorite is SunCalc ( https://suncalc.org )

For a short tutorial on how to use SunCalc please visit https://monarchwatch.org/blog/2021/08/17/some-notes-on-the-sun-angle-at-solar-noon-sasn-and-the-passage-of-the-migration/

Table 1 was assembled using SunCalc, but there is more that can be learned using this site. To get to where I did, think about what the monarchs may or may not be responding to as the season changes. You can get to the answer using suncalc.org, and if you get there, you may react the way I did. It was kind of a eureka moment – except I didn’t say eureka!

If you think you have figured out what these four locations have in common on the dates indicated and have an explanation for why migratory flight probably stops on these dates, send your answer to Monarch Watch at monarch@ku.edu (with “Puzzle Submission” in the Subject line) by the 28th of February 2022. We will reward the three best answers with a copy of the new migration board game “Mariposas”.

A Monarch Puzzle – original text

Get out your pencils!

We know that directional flight (migration) by first generation monarchs that have moved northward stops sometime in June, but we aren’t sure when it stops, where it stops or why. I have an idea based on one data point that may explain the when and why for a series of latitudes. I’m going to explain the observation and tell you when I expect directional flight ends at the latitudes of Ames, IA, St Paul, MN and Winnipeg, Manitoba.

Many years ago, I asked an undergraduate to pay special attention to directional flight by monarchs in late May and June. We knew that first generation monarchs from the South Region (Texas and Oklahoma) were moving through the area at that time on the way north to the summer breeding grounds north of 40N. We also knew that that migration stopped suddenly but we didn’t know when or why. She went to a location with lots of common milkweed patches at which the passing monarchs would stop briefly but then continue flying N/NE. The last day she spotted monarchs moving to the N/NE was the 5th of June. That got me thinking, if I know when they stopped in Lawrence, could I extrapolate from the conditions on the 5th of June to those in other latitudes? Well, I’ve done so, and the prediction is that directional flight should stop in Ames on the 7th, in St Paul on the 9th and Winnipeg on the 12th.

So here is the puzzle: what do the dates at the latitudes represented by these cities have in common with the conditions that occur on the 5th of June in Lawrence, Kansas?

——————————————————
5. About This Monarch Watch List
——————————————————
Monarch Watch ( https://monarchwatch.org ) is a nonprofit education, conservation, and research program affiliated with the Kansas Biological Survey & Center for Ecological Research at the University of Kansas. The program strives to provide the public with information about the biology of monarch butterflies, their spectacular migration, and how to use monarchs to further science education in primary and secondary schools. Monarch Watch engages in research on monarch migration biology and monarch population dynamics to better understand how to conserve the monarch migration and also promotes the protection of monarch habitats throughout North America.

We rely on private contributions to support the program and we need your help! Please consider making a tax-deductible donation. Complete details are available at https://monarchwatch.org/donate or you can simply call 785-832-7374 (KU Endowment Association) for more information about giving to Monarch Watch.

If you have any questions about this email or any of our programs, please feel free to contact us anytime.

Thank you for your continued interest and support!

Jim Lovett
Monarch Watch
https://monarchwatch.org

You are receiving this mail because you were subscribed to the Monarch Watch list via monarchwatch.org or shop.monarchwatch.org – if you would rather not receive these periodic email updates from Monarch Watch (or would like to remove an old email address) you may UNSUBSCRIBE via https://monarchwatch.org/unsubscribe

If you would like to receive periodic email updates from Monarch Watch, you may SUBSCRIBE via https://monarchwatch.org/subscribe

This e-mail may be reproduced, printed, or otherwise redistributed as long as it is provided in full and without any modification. Requests to do otherwise must be approved in writing by Monarch Watch.

Monarch Watch Update January 2022

This newsletter was recently sent via email to those who subscribe to our email updates. If you would like to receive periodic email updates from Monarch Watch, please take a moment to complete and submit the short Google Form at monarchwatch.org/subscribe/

Greetings Monarch Watchers and Happy New Year to all!

As many of you already know, Monarch Watch will be celebrating 30 years of education, conservation, and research in 2022 – WOW! We are not yet sure how we will mark this milestone, but there will certainly be a retrospective component and maybe an event or two. We will keep you informed via our blog, email updates, and social media. Thank you for your continued interest and support!

Included in this issue:
1. How Many Hectares in 2021-2022?
2. Western Monarchs
3. Monarch Watch One Day Fundraising Event
4. Monarch Watch Tagging Kits for 2022
5. Submitting Tag Data
6. Monarch Watch Mobile App
7. Free Milkweed Programs
8. A Monarch Puzzle
9. About This Monarch Watch List

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1. How Many Hectares in 2021-2022? – Chip Taylor
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Each year, at about this time, I administer a test – to myself. I have one question. How big, in term of hectares*, will the overwintering population be this year?

Technically, I fail the test every time and expect to. Realistically, it would be virtually impossible to correctly predict the overwintering numbers given the number of variables involved in each migration.

I look at many factors and draw on the historical record to arrive at a prediction. The conditions during the spring in Texas, the recolonization of the northern breeding areas in May, the summer temperatures, the weather during the migration and the availability of nectar sources in Texas all differ from year to year and all factor into the number of monarchs that reach the overwintering sites. The challenge for me is to assess each of these conditions for a given year and to compare these outcomes with the record that goes back to 1994.

After considering all of these factors for this past season, I came up with the following estimate: 0.8-1.2 hectares. Ouch! That’s low and lower than the 2.01 hectares measured last year. In fact, if 1.2 hectares this year, that would be the lowest number since the winter of 2014-2015. I know that that is not what anyone wants to hear, and I don’t want to accept those numbers myself, but that is what my assessment tells me. My history with these estimates is fair, but I usually underestimate the size of the population which means that I’m overestimating the negative impact of one or more factors. These over and under estimates speak to my goal which is to develop a deep understanding of all the factors that determine the size of the population. Being wrong goes along with learning how to refine my estimates. 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.

For a detailed discussion of this season’s prediction please see the expanded “How many hectares in 2021-2022?” article posted today via the Monarch Watch blog.

*One hectare is equal to 2.47 acres. One acre is approximately the area of a football field exclusive of the end zones.

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2. Western Monarchs – Chip Taylor
——————————————————
My father was a Certified Public Accountant, and had I demonstrated a facility for numbers, I might have become a CPA as well. Instead, I became a biologist which I naively assumed would mean that I wouldn’t have to work with numbers – at least not a lot. As it turns out, understanding monarchs, or more accurately, attempting to understand monarchs, requires a lot of number crunching. But that only works if we have some numbers to work with, and if the numbers are reasonably accurate.

This brings me to a monarch puzzle. Namely, how did the Western monarch population grow from an overwintering number of 1,914 in 2020 to over 200,000 in 2021? Both numbers are based on Xerces-sponsored Thanksgiving Day Counts. Each count involves an examination and estimation of the number of monarchs at 261 known overwintering locations and the search for new sites which are often on private land. At many sites, the number of monarchs is so low, the count is an actual count rather than an estimate. That was mostly the case last year and the Thanksgiving number was followed by an end of the year accounting that produced only 1,049 monarchs. The decline from 1,914 to 1,049 was not unexpected. From the end of a breeding season in September and October (depending on location), the population declines until the end of the first reproductive period in April.

There seem to be three possibilities, 1) monarchs originating from Mexico recolonized the breeding areas in the West in March and April, 2) there were thousands of overwintering monarchs that clustered at sites that have never been discovered or 3) that some monarchs that breed along the coast during the winter months responded to seasonal cues in March and moved inland where they gave rise to a first generation of monarchs that colonized the summer breeding ranges in the West, particularly those areas to the east and north of California.

I’ve attempted to determine if there is support for any of these possibilities and those interested in a deep dive into the numbers should read the expanded “Western Monarchs” article posted today via the Monarch Watch blog.

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3. Monarch Watch One Day Fundraising Event
——————————————————
Monarch Watch will again be featured in the University of Kansas’ annual “One Day. One KU.” 24-hour fundraising campaign which will take place in mid-February. The event will provide an opportunity for Monarch Watchers all over the globe to come together and show their support of our program.

Last year many of you commented that you would’ve liked more notice of this event so this is just a quick heads up before an official announcement that will be made in the coming weeks. Stay tuned!

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4. Monarch Watch Tagging Kits for 2022
——————————————————
Monarch tagging continues to be an important tool to help us understand the monarch migration and annual cycle. We are now accepting PREORDERS for the 2022 fall tagging season and kits will be sent out in the fall, ahead of the migration in your area. If you would like to tag monarchs this year, please order your tags as early as possible!

Monarch Watch Tagging Kits are only shipped to areas east of the Rocky Mountains. Each tagging kit includes a set of specially manufactured monarch butterfly tags (you specify quantity), a data sheet, tagging instructions, and additional monarch / migration information. Tagging Kits for the 2022 season start at only $15 and include your choice of 25, 50, 100, 200, or 500 tags.

Monarch Watch Tagging Kits and other materials (don’t forget a net!) are available via the Monarch Watch Shop online at https://shop.monarchwatch.org – where each purchase helps support Monarch Watch.

Complete information including datasheets and instructions are available on the Monarch Tagging Program page at https://monarchwatch.org/tagging

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5. Submitting Tag Data
——————————————————
Thousands of you have submitted your recent tag data to us by mail or via our online submission form – thank you! We are still receiving data sheets and if you haven’t submitted your data yet (for 2021 or even previous years) it is not too late. Please review the “Submitting Your Tagging Data” information on the tagging program page then send us your data via the Tagging Data Submission Form.

Complete information is available at https://monarchwatch.org/tagging if you have questions about submitting your data to us and we have conveniently placed a large “Submit Your Tagging Data” button on our homepage at https://monarchwatch.org that will take you directly to the online form.

There you can upload your data sheets as an Excel or other spreadsheet file (PREFERRED; download a template file from https://monarchwatch.org/tagging ) or a PDF/image file (scan or photo).

If you have any questions about getting your data to us, please feel free to drop Jim a line anytime via JLOVETT@KU.EDU

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6. Monarch Watch Mobile App
——————————————————
A newly developed Monarch Watch mobile app (for iOS and Android) will make it easier for many taggers to record butterflies as they are tagged and submit data electronically. The beta testing of the app in the last few months has gone well, and we hope to launch it for general use during the 2022 tagging season. We will have much more to say about this in the coming months.

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7. Free Milkweed Programs
——————————————————

For habitat restoration projects

New for Spring 2022 — Free Milkweeds for California restoration!

Monarch Watch will once again be distributing free milkweeds for planting in large-scale habitat restoration projects for Spring 2022. Since this program began in 2015, almost 252,000 milkweeds [edit: more than 650,000 milkweeds] have been planted in restored habitat throughout much of the range of the eastern monarch population. New this year: Help the Western monarch population with FREE MILKWEEDS FOR MOST AREAS OF CALIFORNIA! To qualify, applicants must have a minimum of two acres (one acre in CA) to restore to natural, native habitat, and have a management plan in place. Milkweeds are awarded on a first come, first served basis, so apply early.

Those awarded free milkweeds need only pay shipping/handling, which is modest compared to the value of the plants. Please help us spread the word by sharing widely. For more information and to apply, please visit:

https://monarchwatch.org/free-milkweed-restoration

For Schools and Nonprofits

The Free Milkweeds for Schools and Nonprofits Grant is in its 8th year and we are still distributing free milkweeds to those who qualify. Through the generous support of the Natural Resources Defense Council, this program provides funding for 6000 plants. Each recipient receives one full flat of milkweed plants to be added to a public garden. Schools, libraries, nature centers and museums are examples of past recipients. This program is available to applicants in California and all states east of the Rocky Mountains. The application can be found here:

https://monarchwatch.org/free-milkweed-schools-nonprofits

Sorry, this program is not intended for private yards or free milkweed giveaways.

——————————————————
8. A Monarch Puzzle – Chip Taylor
——————————————————
Get out your pencils!

We know that directional flight (migration) by first generation monarchs that have moved northward stops sometime in June, but we aren’t sure when it stops, where it stops or why. I have an idea based on one data point that may explain the when and why for a series of latitudes. I’m going to explain the observation and tell you when I expect directional flight ends at the latitudes of Ames, IA, St Paul, MN and Winnipeg, Manitoba.

Many years ago, I asked an undergraduate to pay special attention to directional flight by monarchs in late May and June. We knew that first generation monarchs from the South Region (Texas and Oklahoma) were moving through the area at that time on the way north to the summer breeding grounds north of 40N. We also knew that that migration stopped suddenly but we didn’t know when or why. She went to a location with lots of common milkweed patches at which the passing monarchs would stop briefly but then continue flying N/NE. The last day she spotted monarchs moving to the N/NE was the 5th of June. That got me thinking, if I know when they stopped in Lawrence, could I extrapolate from the conditions on the 5th of June to those in other latitudes? Well, I’ve done so, and the prediction is that directional flight should stop in Ames on the 7th, in St Paul on the 9th and Winnipeg on the 12th.

So here is the puzzle: what do the dates at the latitudes represented by these cities have in common with the conditions that occur on the 5th of June in Lawrence, Kansas?

If you think you have figured out what these four locations have in common on the dates indicated and have an explanation for why migratory flight probably stops on these dates, send your answer to Monarch Watch at monarch@ku.edu (with “Puzzle Submission” in the Subject line) by the 31st of January 2022. We will reward the three best answers with a copy of the new migration board game “Mariposas”.

——————————————————
9. About This Monarch Watch List
——————————————————
Monarch Watch ( https://monarchwatch.org ) is a nonprofit education, conservation, and research program affiliated with the Kansas Biological Survey & Center for Ecological Research at the University of Kansas. The program strives to provide the public with information about the biology of monarch butterflies, their spectacular migration, and how to use monarchs to further science education in primary and secondary schools. Monarch Watch engages in research on monarch migration biology and monarch population dynamics to better understand how to conserve the monarch migration and also promotes the protection of monarch habitats throughout North America.

We rely on private contributions to support the program and we need your help! Please consider making a tax-deductible donation. Complete details are available at https://monarchwatch.org/donate or you can simply call 785-832-7374 (KU Endowment Association) for more information about giving to Monarch Watch.

If you have any questions about this email or any of our programs, please feel free to contact us anytime.

Thank you for your continued interest and support!

Jim Lovett
Monarch Watch
https://monarchwatch.org

You are receiving this mail because you were subscribed to the Monarch Watch list via monarchwatch.org or shop.monarchwatch.org – if you would rather not receive these periodic email updates from Monarch Watch (or would like to remove an old email address) you may UNSUBSCRIBE via https://monarchwatch.org/unsubscribe

If you would like to receive periodic email updates from Monarch Watch, you may SUBSCRIBE via https://monarchwatch.org/subscribe

This e-mail may be reproduced, printed, or otherwise redistributed as long as it is provided in full and without any modification. Requests to do otherwise must be approved in writing by Monarch Watch.