Monarch Watch Blog

Monarch Population Status

4 January 2023 | Author: Chip Taylor

Status of the eastern monarch population (as of December 2022)

I’ve said it before, but it bears repeating. Monarch numbers each season are largely due to the timing and numbers from one stage in the annual cycle to the next. Habitat availability, which comes down to the abundance and distribution of milkweeds as well as the nearby sources of nectar, sets the upper limit for monarch numbers. More habitat means more monarchs if the temperatures and rainfall throughout the year are close to the long-term averages. However, the conditions are seldom, if ever, optimal. So, the task, for those of us developing stage specific models for wildlife, is to determine how birth rates and death rates are affected within each stage that determines the number entering the next stage.

The monarch annual cycle can be broken down into six stages: overwintering from November to April, migrating back to the US late February to April, breeding from March to May by returning monarchs, first generation recolonization of the summer breeding areas north of 40N, summer breeding from May to September and migration from August to December.

The area of the forests with monarchs this winter is going to be low – probably one of the all-time low numbers – close to, if not below, 1 hectare (2.47 acres). I could see that the numbers would be down this year as early as late May and nothing happened through the rest of the season to change that assessment.

So, what happened from stage to stage this year? I’ll give you my interpretations with the caveat that the information available on what happened during several stages is either non-existent or inadequate.

Overwintering – November-April.
While the number of hectares of trees with monarchs at the overwintering sites has been recorded every year since 1994, there is no comprehensive understanding of the mortality that occurs each winter. It is known that colonies decline in size through the winter, but whether these declines are associated with offsite mortality or the movement of overwintering colonies is not clear. The only times mortality has been estimated for the majorities of colonies is following major catastrophic events after winter storms (2002, 2004, 2010, 2016). One might think that tag recovery rate would be a good measure of winter mortality. That is surely the case for years with strong winter storms and may apply to other years as well, but overall winter mortality does not appear to be a major determinant of population size from one year to the next.

Migrating North – February-April.
The mortality during the traverse from the overwintering sites to Texas could vary substantially from one year to another due to droughts, excessively high temperatures or a lack of nectar. Monarchs utilize two routes to reach Texas, Figure 1. One, a coastal route of about 600 miles used early in March when temperatures are moderate. This route appears to shut down when the temperatures in Tamaulipas are in the 90s and higher, which is often the case by mid-March. The second, and cooler, route follows the mountains to the north toward Ciudad Victoria and then NW toward Monterrey with a crossing into Texas that takes the monarchs through the Edwards Plateau into central Texas. This route is about 800 miles and essentially duplicates the route of most of the fall migrants. Unfortunately, there is no systematic monitoring of the conditions along these routes. So, what happens from year to year along these pathways and how those conditions impact the proportions of the returning monarchs that reach Texas is unknown.

Figure 1. Spring first sightings reported for Mexico to Journey North. These records suggest monarchs use two pathways to reach the breeding grounds in Texas and beyond.

Fortunately, there is a record of first sightings for the last 23 years thanks to the reporting to Journey North and the leadership of Elizabeth Howard and Nancy Sheehan who have managed that project. To determine if the first sightings tell us something about the timing and number of monarchs arriving from Mexico in the spring, we have compiled all the first sightings from 1March through 30 April for each year. The medians range from 13 March to 2 April and both high and low overwintering numbers followed these early and late median arrivals. The overall, mean is 22 March and the median for 2022 was 25 March.

The numbers recorded each year are also hard to interpret since the number of first sightings reported in Texas has increased over the years from 37 in 2000 to 343 in 2021. Again, there are years when low and high numbers of arrivals are followed by increases and decreases in monarch numbers. Although more digging in the data is warranted, the results suggest that the timing and number of monarchs arriving from Mexico is not a major factor in determining the numbers in most overwintering periods.

Reproduction by returning migrants – March-April.
So, if the timing and numbers of monarchs from Mexico is seldom a factor, that suggests several things. First and second, overwintering mortality is also not a driver in most years nor is the traverse from the overwintering sites to Texas. There are probably years (e.g., 2004) when one or the other or both are important, but that appears to be uncommon relative to other factors that determine end of year numbers.

The temperatures in Texas in March and April have significant impact in determining the size of the population at the end of the cycle. Of the 22 years in the record, the population increased in 10 years and decreased in 12. In 9/10 years with increases, the mean temperatures for Texas were less than +2.5F above the long-term average. The exception to this trend was 2006, a year with a mean temperature for March and April of +5.3F. The number of hectares the following winter increased from 5.92 to 6.87. The explanation for the increase appears to be due to two things: the earliest arriving cohort from Mexico (median = 13 March) and the highest temperatures for April (+5.8F above average) in the entire record from 1895 to the present. The Journey North map of first sightings for the spring of 2006 suggests that early arrival combined with egg laying concentrated in Texas and southern Oklahoma, followed by high April temperatures, led to the rapid development of the larvae and a large cohort of first-generation offspring. These offspring effectively colonized the summer breeding range north of 40N with >75% of the sightings recorded from 21 to 30 May. In contrast to the increases, the population decreased in 6/7 years in which the mean temperatures were in excess of 2.5F. The exception being 2006. For the other 6 years, other factors account for the decreases. For example, decreases followed the two coldest June-August periods (2004, 2009) and late recolonizations north of 40N account for low numbers in 2013 and 2019. The declines of 2002 and 2007, which should have been increases based on March/April temperatures, remain unexplained.

First generation colonization of the summer breeding range north of 40 North

First generation monarchs, mostly originating from eggs laid by monarchs returning from Mexico in Texas and Oklahoma, begin migrating north in the last week of April. This migration appears to continue until the difference in daylength from one day to the next drops below one minute per day at each latitude (https://monarchwatch.org/blog/2022/04/22/monarch-puzzle-wrap-up/). This result indicates that the migration northward stops progressively from south to north with the last of the migration stopping on or about 12 June at 50N.

Applying the dictum that it is timing, numbers and weather that mostly determines the number of monarchs transitioning from one stage to another produced some interesting results. We summarized all the first sighting for longitudes north of 40N latitude. I’m going to refer to the areas defined by 100-90W and 90-80W bounded by latitudes 50 to 40N. These two areas account for about 90% of the recoveries of tagged butterflies in Mexico. The interval for these first sighting is from 1 May to 9 June, a 40-day period divided into 10-day intervals. When we tallied the first sightings for the 23-year interval, two years stood out: 2012 and 2013. In 2012, 92% of the first sightings occurred from 1-20 May while in 2013 only 5% of the first sightings occurred during that interval. The numbers of sightings in 2012 was >2x the number in 2013. The expectation therefore was that the population in 2012 would increase, but it declined. The starting numbers in 2013 also resulted in a decline leading to the conclusion that arriving in the northern breeding areas too soon (2012), perhaps before milkweed is available, or too late (2013), resulting in a delay in starting the summer breeding, can both result in a decline in the size of the migration and the overwintering population. Looking at these two extremes, it seemed appropriate to ask whether there is an optimal time of arrival in the northern breeding areas. Perhaps there is, but that is not evident in the data. There are at least two complications: the phenology of the milkweeds and nectar sources varies from year to year, and the weather after arrival can have a strong impact on the outcome. That’s what happened this year. Fifty-four percent of the first sightings were recorded from 1-20 May, and the numbers were good. Most of the monarchs were sighted during a warm period from 8-20 May. Cold weather followed for 4-7 days over a broad area during which the temperatures were too low most days for egg laying, mating or foraging for nectar. Once I became aware of that, I knew the population would be lower at the end of the season. Populations grow best when egg laying is not interrupted. Delays result in attrition of adults and the ability to continue producing eggs declines with age.

In putting this summary together, I looked for other factors that could explain why the numbers in the migration were low. Although there were a number of complaints of high temperatures and drought conditions from a number of places in the Midwest, scans of the temperatures and rainfall amounts failed to confirm either were extreme. Nor were there other explanations for the low numbers. So, the best I can offer is the likelihood that the interrupted reproduction in the 4th week of May accounts for the low migration and what seems certain to be a low overwintering population.

The Fall Migration – a traverse from 50N to 19.5N beginning in early August and ending in early December.

To assess the success of each migration, I try to determine the lateness of the migration, the numbers tagged, the number and sizes of the roosts reported to Journey North and whether there are drought conditions along the route. I also monitor weather conditions since extremes determine migratory success.

Monarchs tagged late in the season have a much lower chance of reaching the overwintering sites than those tagged early. The same applies to entire migrations. Migrations can be delayed by extremely high or low temperatures, strong headwinds and delayed development of the last generation due to late arrival of monarchs colonizing the breeding areas in May and June.

We also know that the numbers tagged is correlated with the size of the overwintering population. The number of roosting sites and estimates of the numbers per roost can also be useful. Extreme high or low numbers are informative, but intermediate numbers may or may not predict overwintering numbers. We also know that droughts contribute significantly to monarch mortality.

We will have to wait until the tagging data is analyzed to determine if there was more late tagging than usual this year, but that seems unlikely given how the season progressed during June through August. Also, although the temperatures were higher than the long-term averages during September in the Midwest Region and October in the South Region, there are no indications the migration was substantially delayed by the weather.

The temperatures in the vicinity of the overwintering colonies for the last 4 days of Oct, a period during which monarchs are usually spotted in the area, were quite cold and evidently delayed the arrival of the leading monarchs. However, some monarchs appeared near El Rosario on the first of November just in time for the Day of the Dead on the following day. Monarchs were slow to form clusters through November and remained quite scattered in the El Rosario area until late in the month. Whether this scattering will affect the measurements of colonies in early December remains to be seen.

The numbers tagged from 1 August to the end of the season and submitted by 30 November 2022 were only 64% of the number tagged in 2021 (54K/91K), Table 1. This figure could change as more data are received, but since numbers tagged are correlated with overwintering numbers, this result suggests that overwintering numbers will be substantially lower than those of the previous 4 years.

Table 1. A summary of the number of monarchs tagged from 1 August to the end of the season for records submitted by 30 November.

The number of temporary roosts reported to Journey North was also the lowest of the last 5 years, again suggesting lower numbers this winter, Table 2. Although roost numbers and colony numbers appear to be correlated p=0.01, a deeper dive into these data that eliminates roosts west of the continental divide and Mexico, as well as the roosts with single butterflies, or an analysis of roosts by latitude and longitude could produce different results. The numbers per roost could also affect the interpretation.

Table 2. Fall roosts as reported to Journey North, (maps.journeynorth.org/map/?map=monarch-roost-fall&year=2022).

Droughts, such as those of 2000 and 2011 that limit the amount of flowering and therefore nectar available to migrating monarchs, can have a significant impact on the number reaching the overwintering sites. There were areas of exceptional drought in portions of southern Kansas, Oklahoma and Texas and severe drought much of the migratory route in northern Mexico, Figure 1. How successful monarchs were in locating nectar under these conditions has yet to be determined, but all past measures of greenness suggest that the conditions this fall probably limited the number of monarchs reaching the overwintering sites.

The above is my rationale for saying at the outset that the area occupied by overwintering monarchs would be close to, if not below, 1 hectare (2.47 acres). As always, these predictions are a test of the value of the metrics and/or how they are applied to the question. This stage-specific approach reveals massive data gaps and shows us how little we know about monarch demography. This approach also allows us to see that not everything is linear. There are many optima to consider (see Why monarchs are an enzyme). For example, populations decline if the growing season temperatures are too high or too low and grow substantially when the temperatures are close to the long-term average. Arriving early in breeding grounds can get the population off to a good start (2006) or a bad start (2012) depending on the availability of milkweeds and nectar sources and the weather conditions that follow (2022). Lastly, a comprehensive demographic approach to the entire annual cycle will help us avoid interpretative leaps that are misleading or just flat-out wrong.

Figure 1. North American Drought Monitor 30 September 22

Acknowledgements

Much of this analysis is based on the use of the first sightings data assembled by Journey North. These data help define the timing of the stages and the variations from year-to-year help define how weather and the conditions from one stage to another determine population growth. Janis Lentz worked up the data on the first sighting for both Texas and the monarchs colonizing the summer breeding range. She also assisted with my grammar, punctuation and sentence structure. (She doesn’t like long sentences). Jim Lovett provided technical assistance.

Suggested Reading

Taylor, O.R., Lovett, J.P, Gibo, D.L., Weiser, E.L., Thogmartin, W.E., Semmens, D.J., Diffendorfer, J.E., Pleasants, J.M., Pecoraro, S.D., and Grundel, R. (2019). Is the timing, pace and success of the monarch migration associated with sun angle? Frontiers Ecology Evolution. published: 10 December 2019 doi: 10.3389/fevo.2019.00442

Taylor, O.R., Pleasants, J.M., Grundel, R., Pecorraro, S.D, Lovett, J.P, and Ryan, A. (2020) Evaluating the migration mortality hypothesis using monarch tagging data. Front. Ecol. Evol. | doi: 10.3389/fevo.2020.00264

Taylor, O. R. (2020). Why monarchs are an enzyme – Part 1
monarchwatch.org/blog/2020/02/10/why-monarchs-are-an-enzyme-part-1/

Filed under Monarch Population Status | Comments Off on Monarch Population Status

Migrating with Monarchs

28 November 2022 | Author: Jim Lovett

by Denise Gibbs

Currently, I am a Monarch Conservation Specialist for Monarch Watch. Before that, I had a career as an interpretive naturalist, native plant nursery owner specializing in nectar and host species for butterflies, and teacher of a graduate course focused on butterfly conservation. But by far, my most satisfying endeavor (at the late Dr. Lincoln Brower’s urging) was researching Monarch migration and roosting behavior for the Chincoteague Monarch Monitoring Project at Chincoteague National Wildlife Refuge and Assateague Island National Seashore on Assateague Island, Virginia. For 23 fall seasons (mid-Sept to late Oct) I collected quantitative data from a 3X daily Pollard transect (driving census) on refuge roads, a daily point count on the primary dune, and 3X weekly count from the top of a hawk watch tower. In between, I netted and tagged Monarchs. I also conducted impromptu Monarch interpretation and tagging demonstrations for visitors on the beach and on the refuge’s tram tour. The data and my recommendations were included in a Monarch management plan for the refuge which was implemented and continues to benefit migratory Monarchs utilizing the refuge’s resources. But there was just one thing missing. I wanted to know where the Monarchs went after they left the island. I wanted to witness and experience the next phase of their journey…

From mid-Sept to late October 2022, my husband Rob and I journeyed along with Monarchs as they migrated along the Atlantic and Gulf coasts.

The day we left our home in the Verde Valley of central Arizona, our yard was nurturing all life stages of Monarchs. I wished them well and we headed north on I-17, which was lined in fields of gold — sunflowers, goldenrod, golden crownbeard, and goldeneye. AZ had an abundant and extended monsoon season this year — wildflowers and butterflies (including Monarchs) flourished. From Flagstaff, we drove on I-40 toward the East coast. As we traveled, high winds from the south were so strong we feared that Swan (our tall campervan) might be blown into other lanes on overpasses and bridges. Rob drove and I watched for migrating monarchs, but saw none; the wind was not favorable for Monarch flight southward. We drove through 9 states, but I didn’t see a migrating Monarch until a week later in downtown Norfolk, Virginia.

After that, we saw Monarchs every day at every place we stopped. We had several good Monarch migration days on the Delmarva peninsula and its barrier islands — at Assateague Island State Park in MD and Chincoteague National Wildlife Refuge (CNWR) in VA, before we got slammed with Hurricane Ian’s gale-force winds and coastal flooding. The rain was needed. monarch on vanPast years’ wet fields and ditches of Bur-marigold (Bidens laevis) were dry and barren this year. The rains came too late for them, but boosted the blooms of Seaside goldenrod (Solidago sempervirens), which were already late in opening their flowers. The first big wave of migrating Monarchs had to fly further inland from their migratory path along the beach to find the other two species of goldenrod that were in bloom: Slender and Grass-leaved. Groundsel-tree (Baccharis halimifolia) was beginning its bloom and was utilized by migrating Monarchs as well. As usual at CNWR, the wind was variable, and on most days the Monarchs flew (constantly flapping) in less-than-ideal winds. They stopped often to rest in places protected from the wind. Beach parking was limited after the hurricane removed all the public parking lots, so we had to park Swan along the narrow, exposed causeway. This proved to be fortunate for the Monarchs, because they used the vehicle as a wind block and as a place to rest (see photo).

When Bayberry/Groundsel-tree thickets were available, Monarchs would take refuge from the wind in the dense vegetation. But if they rode the wind to the over-washed beach area, they had to find other ways to avoid being blown out over the ocean. On a day with a 20-30 mph NW wind, a Monarch wedged itself in a crack in a wooden board along the saltmarsh boardwalk trail, while others clung to short plant stems on the beach (see photos below).

We left Virginia’s barrier islands and headed south, stopping to camp the first night at Kiptopeke State Park, which is at the southern tip of the Delmarva. With south winds, Monarchs were bottled-up, waiting for a north wind that would carry them safely and swiftly across the Chesapeake Bay to Virginia Beach. (We learned from a friend that their departure en mass actually occurred 5 days after we had left). In the photos below, Monarchs were hunkered down in the Bayberry thickets along the Eastern shore of the Chesapeake Bay when they were not nectaring on the abundant patches of Seaside goldenrod.

We headed south toward Florida, following coastal routes. We stopped at nature centers, welcome centers, and visitor centers. It was encouraging to see that every one of them had a pollinator garden. Some were simply wild patches they had allowed to grow; others were intentionally planted small token gardens, and a few had extensive professionally-designed beds. I did not see any Monarch Waystation signs, but I did see plenty of Monarchs in every garden. Nectar sources included native asters, goldenrods, and Blue mistflower. Only a few gardens contained milkweed— Butterfly weed and/or Tropical milkweed.

We also stopped frequently at every town that had available RV parking (with easy access to the ocean or a bay) to look for Monarchs. We saw them at EVERY place we stopped in VA, NC, SC, and GA. Back Bay NWR in VA was particularly good. Most often, the Monarchs we saw were refueling in patches of goldenrod instead of migrating. We hit the Monarch jackpot on a N wind day at Huntington Beach State Park in SC — a continuous stream of Monarchs flying low (10-20′ high) over the dry sand portion of the beach on a perfect N wind. There easily could have been 10,000 Monarchs by the end of the day (see photo).

Our final stop on the Atlantic coast was the beach at Tybee Island GA, but saw only a few Monarchs in a town-square pollinator garden with Lantana and Tropical milkweed. We turned inland, avoided the interstate, and took alternate routes to St Mark’s National Wildlife Refuge in FL. Roadside nectar sources were abundant but we saw only a few monarchs en route. We spent 2 days at the refuge. Winds were SW or S, so we saw no migrating monarchs — just those that were bottled-up at Lighthouse Point, nectaring on goldenrod, and waiting for the wind direction to shift in their favor. Gulf fritillaries by the hundreds kept the nectaring Monarchs company (see photos below).

The gulf coast from Florida to Texas was surprisingly good. We saw Monarchs everywhere we stopped to look for them. At Point Park Pascagoula, MS (near the birthplace of Jimmy Buffett), we hit another Monarch jackpot. In the 30 minutes that I walked down Buffett Beach, I counted over 1000 monarchs as they flew past me at eye level on a 10-20 mph N wind. Once they reached the point, they stopped to nectar in a dense thicket of Groundsel-tree. There were thousands still nectaring in those thickets when we left at dusk.

Our last stop on the gulf coast was at Sea Rim State Park, TX (NE of Galveston). We arrived at 3:30 PM and made a beeline for the beach. Low tide revealed a wide flat beach where Monarchs were migrating. I counted 52 from 4-4:30. (That was close to the number that Harlen had counted on his driving census along Lavaca Bay the same day). Then at 4:30, Monarchs started dropping down into a wide flat dune area full of goldenrod and other wildflowers. I counted a few hundred nectaring, but the area was so extensive (about 100 x 300 yards) that there were likely many more I couldn’t see. While searching, I found this pair mating (see photos).

Reluctantly, we left the Gulf coast and drove west on I-10 across Texas. We continued to see monarchs crossing the highway from north to south, particularly in the Texas Hill Country. In Kerrville, Monarchs were migrating along the Guadalupe River, stopping to nectar on Bidens and Blue mistflower (see photos below). The last migrating Monarch we saw in TX was in Ozona.

We crossed the state line into New Mexico on Oct 21. I continued to watch for those orange beauties as we drove west toward AZ. We saw no Monarchs in NM. There had already been below-freezing night temperatures and the roadside wildflowers were dead. Another cold front the next day caused the temperature to plummet, and snow was in the forecast for AZ’s White Mountains (our intended route home). Instead we stayed on I-10 to avoid the snow. We stopped in Wilcox to watch the arrival of thousands of Sandhill Cranes. Fleabane and Tansyaster were still blooming around the playa and were luring in Variegated fritillaries, Checkered whites, Queens, Checkered and Fiery skippers — but no Monarchs. Our final campsite of the trip was in the Sonoran Desert near Tucson. There were plenty of Monarchs present, so I felt like we had come full circle.

Final thoughts:
From 23 Fall seasons of watching migratory behaviors of Monarchs on Assateague Island, I already had a deep respect and appreciation for their ability to endure hardships and survive hurricanes, nor’easters, and flooded roosting sites. But all along this trip route, I was in awe of their continued resilience. Their ability to keep migrating despite obstacles was astonishing. They flapped directly into SW and S winds, endured long distances with a scarcity of nectar sources, and hunkered down on days with torrential rain, cold temperatures, gale-force winds, and coastal flooding. Along the Gulf coast they flew over developed beaches with no habitat, through the hazy polluted stench of paper mill exhaust, and over shipyards blasting ear-shattering horns and sirens. They took shelter in the most unlikely and inhospitable places. They got blown backwards or out over the ocean on extremely unfavorable winds, but kept flapping to stay true to their directional flight. The migratory urge (compulsion, drive, stimulus — however you want to describe it) keeps them going — against all odds. There’s a lesson in that for all of us.

map of monarch sightings

Monarch icons indicate locations with significant numbers of Monarchs — either migrating, nectaring, roosting, or all three.

Filed under Monarch Migration | Comments Off on Migrating with Monarchs

Share photos, videos, stories and more with Monarch Watch

8 August 2022 | Author: Jim Lovett

We are always looking for monarch photos, videos, stories and more for use on our website, on our social media accounts, in our publications, and as a part of other promotional and educational items we distribute online and offline to promote monarch conservation and Monarch Watch.

To help us celebrate 30 years of Monarch Watch, we’d like you to send us your favorites! We will display some of them at the events and share them via our social media accounts and on our website as well. For photos, we prefer the original image resolution and file size to give us the greatest flexibility in using them. Please only submit your own materials.

There are several ways you can send us your favorite files and all of the methods below are accessible via monarchwatch.org/share

1. Main submission form at monarchwatch.org/share/submit
This is the form we prefer you use as it is the most comprehensive and allows you to provide complete information.

2. Quick uploader for photos and videos at monarchwatch.org/share/photos
Note that this method does not allow you to include contact or other information.

3. If you have issues using either of the tools above you may also email your submission to us at share@monarchwatch.org but please include everything we ask for on the main form by copying/pasting the information below into your email message (or use it as a guide).

Name:
Email address:
Do you want to be credited when we use your materials, when feasible?
Name as you would like it to appear in credit:
Description of materials or other comments (for photos and videos this should include an approximate date of capture and location):

Please note that by sharing materials with Monarch Watch you agree to the statements provided at monarchwatch.org/share regarding their origin and use.

Thank you for your interest in sharing with us!

Filed under General | Comments Off on Share photos, videos, stories and more with Monarch Watch

Invitation to Monarch Watch 30-year events

5 August 2022 | Author: Jim Lovett

Come celebrate 30 years of Monarch Watch with us in Lawrence, Kansas! We are planning special events for September 15-17, 2022 and hope you will join us. Space is limited, so please reserve your place as soon as possible. Event registration will close when capacity is reached or at the latest, August 24th. Complete event, location, hotel, travel, ticketing and RSVP details (everything you need to know to plan your visit) are now available online at the link below.

Monarch Watch 30-year events: monarchwatch.org/events

Here is a quick overview of what we have planned:

Thursday, September 15 – Banquet
Join us for a banquet and program highlighting 30 years of Monarch Watch. There will be ample opportunity to socialize with Chip, fellow monarch enthusiasts and Monarch Watch staff. $60/person

Friday, September 16 – Symposium & Evening in the Garden
Attend a monarch update symposium, enjoy a boxed lunch with participants and engage in discussion. $15/person

Later, have a relaxing stroll through Monarch Waystation #1 where Monarch Watch staff and Douglas Co. Extension Master Gardeners will be available to answer questions. Free event.

Saturday, September 17 – Monarch Tagging
We will provide tags, nets, and instruction then send you out into the wetlands to tag some wild monarchs as they migrate through the area. The Baker Wetlands encompasses 927 acres of rich, natural wildlife and is one of the most diverse habitats in Kansas. Free event.

There are also a number of monarch-related activities going on in Lawrence throughout September and we will post details at monarchwatch.org/events once we have them.

We hope you can join us for one or all of the events but if you can’t, we plan to share them with you through photos, video, and maybe even some livestreaming so be sure to check the event page in the coming weeks!

Filed under Events | Comments Off on Invitation to Monarch Watch 30-year events

Monarch Watch Update July 2022

28 July 2022 | Author: Jim Lovett

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.

It is with heavy hearts that we start this month’s communication by sharing this tragic news with the Monarch Watch community:

Three family members, formerly of Lawrence, killed in ‘senseless’ shooting in Iowa
https://lawrencekstimes.com/2022/07/23/schmidt-family-killed-iowa-shooting

Sarah worked for Monarch Watch in the early 2000s and she and Tyler both contributed greatly to Monarch Watch’s development and continuation. We are absolutely shocked by this horrific act of violence. Our thoughts are with all of Sarah’s family members as they try to move forward during this unimaginably difficult time. A GoFundMe campaign has been set up for her 9-year-old son who survived the attack.

Included in this issue:
1. Monarch Population Status
2. Monarch Watch Tagging Kits for 2022
3. Submitting Tag Data
4. Tagging Wild and Reared Monarchs
5. Monarch Waystations
6. Monarch Calendar Project
7. Upcoming Monarch Watch Events
8. IUCN Red Listing of Monarchs
9. About This Monarch Watch List

——————————————————
1. Monarch Population Status
——————————————————

Each year at this time I summarize what I know about how the monarch population is developing. The idea is to give taggers a heads-up about what to expect during the migration. The trouble with this exercise is that the available data are often contradictory (like this year) and there never seem to be a sufficient number of observations. Also, there is often a lull in monarch activity in early July which can be misleading and critical weather information, particularly temperature summaries, needed to assess population growth can also be lagging. Ok, that sums up my excuses. Here is what I do know, based on first sightings reported to Journey North and temperatures from 8 Tempest weather stations scattered from eastern North Dakota to central Ohio.

The monarchs returning from the overwintering sites in Mexico arrived in Texas in noticeable numbers between 11-15 March which fits with the long-term pattern of arrivals. The numbers reported were somewhat lower than last year but average for the last 5 years. I was a bit concerned about the returning numbers at the time, but the overall timing and numbers reported suggested the population was off to a fairly good start.

I next focused on the timing and number of first-generation monarchs moving north out of Texas in May. The first two weeks of May can be a low period for first sightings, but there was a surge of these in the central part of the Midwest from about 10-20 May. That was something to cheer about since that push northward, aided by strong SW winds, was a sign that the population in the Upper Midwest would be off to an early start. But that was not to be. A week of cooler, less favorable, weather followed in many areas. In fact, there were large areas in the eastern Midwest where the cooler weather lasted for three weeks, substantially slowing population development. Added to these conditions, the total number of first sightings in the Upper Midwest was the lowest since 2019 and strikingly low for the area from Madison, WI to the central Dakotas (90-100W longitudes). It is this region that is best represented by tag recoveries in Mexico. Together, delayed development and lower-than-average numbers suggest that the migration in the Midwest will be lower than average in late August and September. It will also be later, which will enable taggers to in many areas to tag monarchs well into September in the north and October in the south.

While the peak colonization of the area from the mid Dakotas (100W) to western Pennsylvania (80W) occurred from 11-20 May, colonization to the east (80-60W) peaked from 21-30 May. The difference in timing between the Midwest and East was unlike any record in the past for May. In addition, the numbers reported in the east were the highest in the 22-year record. These reports amounted to 38% of all sightings. The numbers included 30 sightings in the Maritime provinces – almost double the previous high (17) for that region. The record of colonization in the east may or may not signal a larger than average migration in the east; it is simply too early to tell. But, like the Midwest, it seems likely that the migration will be late and offer an opportunity for tagging well into September and early October along the eastern monarch flyways.

——————————————————
2. Monarch Watch Tagging Kits for 2022
——————————————————

Monarch tagging continues to be an important tool to help us understand the monarch migration and annual cycle – a long-term record is crucial to understand the dynamics of such complex natural phenomena. Tags for the 2022 fall tagging season are available and we have started shipping preorders out this week, ahead of the migration in your area. If you would like to tag monarchs this year, please order your tags soon! Tagging Kits ordered now should arrive within 10–14 days but priority will be given to preorders and areas that will experience the migration first.

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 shop.monarchwatch.org – where each purchase helps support Monarch Watch.

2022 datasheets and instructions are available online via the Monarch Tagging Program page at monarchwatch.org/tagging

Tagging should begin in early to mid-August north of 45N latitude (e.g. Minneapolis), late August at other locations north of 35N (e.g., Oklahoma City, Fort Smith, Memphis, Charlotte) and in September and early October in areas south of 35N latitude. See a map and tables with expected peak migration dates and suggested dates to begin tagging on the Monarch Tagging Program page at the link above.

——————————————————
3. Submitting Tag Data
——————————————————

Thousands of you have submitted your 2021 season 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 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 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 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

Coming Soon: we plan to have the Monarch Watch mobile app available in the App Store (Apple iOS) and Google Play (Android) in August which will allow you to record and submit your tag data, report recoveries of tagged monarchs, participate in the Monarch Calendar program, and more! We will announce the app via social media and you can keep checking our site for updates at monarchwatch.org/app

——————————————————
4. Tagging Wild and Reared Monarchs
——————————————————

As a reminder, the following is an abbreviated version of our “Tagging wild and reared monarchs: Best practices” article posted to our Blog in 2019. The complete text of the article is available via the link below.

Diving into the tagging data has revealed a number of surprises such as the difference between the probability that a reared monarch will reach Mexico and the probability that a wild–tagged monarch will do so. The recovery rate is higher for wild–caught monarchs (0.9% vs 0.5%) and it is the data from the wild–caught butterflies that tell us the most about the migration. Frankly, for some analyses, we have to set the reared monarch data aside. That doesn’t mean it is not valuable, but its uses are limited.

It should be noted that for tagging data purposes, monarchs captured as adult butterflies should be reported as WILD and adult monarchs reared from the egg, larva, or pupa stage should be considered REARED.

TAGGING WILD-CAUGHT MONARCHS
For wild-caught monarchs we need to:
1. increase the number of taggers from western Minnesota and Iowa westward into Nebraska and the Dakotas to give us a more complete understanding of dynamics of the migration;

2. increase the number of wild monarchs that are tagged since these provide the most valuable data; and

3. increase the number of taggers who tag from the beginning of the tagging season in early August until the migration ends. Tagging records for the entire season will help us establish the proportion of the late–season monarchs that reach the overwintering sites. When tagging wild–caught monarchs, many taggers run out of tags well before the season ends. That’s great, but it would help us to know when all tags had been used by indicating this via the online tagging data submission form.

TAGGING REARED MONARCHS
Reared butterflies tend to average smaller than wild migrants. That difference can be reduced significantly if careful attention is given to rearing larvae under the best possible conditions. Large monarchs have the best chance of reaching Mexico, surviving the winter and reproducing in Texas. There are several reasons for this: better glide ratio, better lift with cross or quartering winds, larger fat bodies, more resistance to stress, etc. There are very few small monarchs among those that return in the spring. For those of you who prefer to rear, tag and release, we have a few suggestions:

1. Rear larvae under the most natural conditions possible.

2. Provide an abundance of living or fresh-picked and sanitized foliage to larvae.

3. Provide clean rearing conditions.

4. Plan the rearing so that the newly-emerged monarchs can be tagged early in the migratory season (10 days before to 10 days after the expected date of arrival of the leading edge of the migration in your area).

5. Tag the butterflies once the wings have hardened and release them the day after emergence if possible.

6. When it comes to tagging, tag only the largest and most-fit monarchs (see complete article for some guidelines). Records of tags applied to monarchs that have little chance of reaching Mexico add to the mass of tagging data, but do not help us learn which monarchs reach Mexico – unless the measurements, weight and condition of every monarch tagged and released is recorded. There are a few taggers who keep such detailed records and those data can be very informative. If you collect such data and are willing to share it please contact us; do not add this information to the standard tagging data sheet.

As a final note, this text is not a directive. We are not telling you what to do; rather, we are simply providing suggestions that may lead to more successful rearing and tagging efforts. The expanded version of this article is available at

Tagging wild and reared monarchs: Best practicesmonarchwatch.org/blog/tagging-best-practices

——————————————————
5. Monarch Waystations
——————————————————

To offset the loss of milkweeds and nectar sources we need to create, conserve, and protect monarch butterfly habitats. You can help by creating “Monarch Waystations” in home gardens, at schools, businesses, parks, zoos, nature centers, along roadsides, and on other unused plots of land. Creating a Monarch Waystation can be as simple as adding milkweeds and nectar sources to existing gardens or maintaining natural habitats with milkweeds. No effort is too small to have a positive impact.

Have you created a habitat for monarchs and other wildlife? If so, help support our conservation efforts by registering your habitat as an official Monarch Waystation today!

monarchwatch.org/waystations

A quick online application will register your site and your habitat will be added to the online registry. You will receive a certificate bearing your name and your habitat’s ID that can be used to look up its record. You may also choose to purchase a metal sign to display in your habitat to encourage others to get involved in monarch conservation.

As of 5 July 2022, there have been 39,570 Monarch Waystation habitats registered with Monarch Watch! Texas holds the #1 spot with 3,338 habitats and Illinois (3,046), Michigan (2,901), California (2,516), Ohio (2,073), Florida (2,010), Virginia (1,754), Wisconsin (1,712), Pennsylvania (1,705) and Ontario (1,281) round out the top ten.

You can view the complete listing and a map of approximate locations via monarchwatch.org/waystations/registry

——————————————————
6. Monarch Calendar Project
——————————————————

For those of you participating in our Monarch Calendar project for 2022 (complete details and short registration form at monarchwatch.org/calendar), observation Period 1 has ended (the final date being June 20th, for those of you north of 35N). Once you have logged all of your observations using whatever format works for you (spreadsheet, notebook, calendar, etc.), please use the appropriate online form to submit your data to us:

2022 Period 1 Submission Forms:

—————————————-
SOUTH (latitude less than 35N)
—————————————-
Form for Period 1 (15 March – 30 April): forms.gle/fp7P1QM38CyCWWWa8

—————————————-
NORTH (latitude greater than 35N)
—————————————-
Form for Period 1 (1 April – 20 June): forms.gle/7FfUaywratxLbG7u5

The second observation period runs from 15 July–20 August in the North and 1 August–25 September in the South. As soon as the fall period ends for all locations we will send out links for submission of that data to all who have registered.

Again, complete details and a link to the short registration form are available at monarchwatch.org/calendar

——————————————————
7. Upcoming Monarch Watch Events
——————————————————

Monarch Watch Tagging Event (Free event)
Saturday, September 17, 2022
Baker Wetlands Discovery Center
Lawrence, Kansas
monarchwatch.org/tag-event

We have other events we are planning for the fall and will announce soon. Stay tuned!

——————————————————
8. IUCN Red Listing of Monarchs
——————————————————

The recent news about the IUCN’s Red List does not change the status of monarchs in the U.S.

In a December 15, 2020 press release, the U.S. Fish and Wildlife Service announced its decision with respect to the petition to declare the monarch a “threatened” species under the Endangered Species Act:

“After a thorough assessment of the monarch butterfly’s status, the U.S. Fish and Wildlife Service (Service) has found that adding the monarch butterfly to the list of threatened and endangered species is warranted but precluded by work on higher-priority listing actions. With this decision, the monarch becomes a candidate for listing under the Endangered Species Act (ESA), and its status will be reviewed each year until it is no longer a candidate.”

Upon that announcement, we wrote that the “warranted but precluded” decision for monarchs is the right one at this time. It acknowledges the need for continued vigilance due to the numerous threats to the population while emphasizing the need to continue support for programs that create and sustain habitats for monarchs. It also should be clear that it is the North American monarch migration that is threatened and not the species, which is widely distributed in the Americas and elsewhere.

Please see our full response to this posted via our blog in 2020 at monarchwatch.org/blog/2020/12/15/esa-listing-decision-for-the-monarch/

Thank you for your interest and concern!

——————————————————
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.

Filed under Email Updates | Comments Off on Monarch Watch Update July 2022

IUCN Red List and the status of monarchs

21 July 2022 | Author: Jim Lovett

The recent news about the IUCN’s Red List does not change the status of monarchs in the U.S. In a December 15, 2020 press release, the U.S. Fish and Wildlife Service announced its decision with respect to the petition to declare the monarch a “threatened” species under the Endangered Species Act:

“After a thorough assessment of the monarch butterfly’s status, the U.S. Fish and Wildlife Service (Service) has found that adding the monarch butterfly to the list of threatened and endangered species is warranted but precluded by work on higher-priority listing actions. With this decision, the monarch becomes a candidate for listing under the Endangered Species Act (ESA), and its status will be reviewed each year until it is no longer a candidate.”

Upon that announcement, we wrote that the “warranted but precluded” decision for monarchs is the right one at this time. It acknowledges the need for continued vigilance due to the numerous threats to the population while emphasizing the need to continue support for programs that create and sustain habitats for monarchs. It also should be clear that it is the North American monarch migration that is threatened and not the species, which is widely distributed in the Americas and elsewhere.

Please see our full response to this posted via our blog at monarchwatch.org/blog/2020/12/15/esa-listing-decision-for-the-monarch/

Thank you for your interest and concern!

Filed under Monarch Conservation | Comments Off on IUCN Red List and the status of monarchs

Monarch numbers in Mexico: predictions and reality

24 May 2022 | Author: Chip Taylor

I was wrong, really, really wrong, and I’m happy about it. The numbers are in and they are much greater – 2.84 hectares – than I predicted. In my January 6 post “How many hectares in 2021-2022?“, I went to great lengths to explain why I expected the overwintering monarch numbers to be somewhere close to 0.80-1.2 hectares. I based my expectations on the anticipated impact of the drought in much of the Upper Midwest last summer, the extreme temperatures in July and August in that region, the later than average migration, the lower number of roosts reported to Journey North and the lack of emails declaring that large numbers of monarchs had been seen. None of those metrics hinted at a population larger than the 2.1 hectares recorded in 2020. Everything tended lower.

So, how did these metrics fail me or how did I fail to grasp their meaning? I’m not sure. I’ll try to reassess my approach. Alternatively, are there better metrics? The answer is yes. In the future, I will be using a different set of measures, ones that appear to be better at predicting how the population develops each year. Or, maybe I should follow John Pleasant’s lead and work out a way to count “eggs per stem” at a specific time each year. That’s what John does near Ames, Iowa and his predictions are often better than mine. This year, John wrote “My estimate was 2.1 with a margin that topped out at about 3”. Not bad – 2.84 vs “about 3”. Beats me!

Filed under Monarch Population Status | Comments Off on Monarch numbers in Mexico: predictions and reality

Monarch Population Status

24 May 2022 | Author: Jim Lovett

The WWF-Telmex Telcel Foundation Alliance, in collaboration with the National Commission of Natural Protected Areas (CONANP), the National Autonomous University of Mexico (UNAM), and the Monarch Butterfly Biosphere Reserve (MBBR), announced the total forest area occupied by overwintering monarch colonies today. Ten (10) colonies were located this winter season with a total area of 2.84 hectares, a 35% increase from the previous season (2.10 ha):

monarch-population-figure-monarchwatch-2022
Figure 1. Total Area Occupied by Monarch Colonies at Overwintering Sites in Mexico.

WWF notice: Aumenta 35% la presencia de mariposas Monarca en los bosques de hibernación de Michoacán y el Estado de México

Report (spanish): Monitoreo de la colonias de hibernación de la mariposa monarca en México

WWF story: Eastern monarch butterfly population shows signs of recovery

Report (english): Areas of forest occupied by the colonies of monarch butterflies in Mexico during the 2021-2022 overwintering period

The WWF-TELMEX Telcel Foundation Alliance collaborates with CONANP to systematically monitor the hibernation of the Monarch since 2004, and they join the Institute of Biology of the National Autonomous University of Mexico (UNAM) to analyze changes in forest cover in the area core of the Monarch Butterfly Biosphere Reserve in order to have scientific bases that support the implementation of conservation strategies for the benefit of the species, ecosystems and human beings.

Filed under Monarch Population Status | Comments Off on Monarch Population Status

Monarch Watch Update May 2022

21 May 2022 | Author: Jim Lovett

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

——————————————————
1. Monarch Watch Open House & Spring Plant Fundraiser
——————————————————

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!

——————————————————
2. Follow Monarch Watch on LinkedIn
——————————————————

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 🙂

——————————————————
3. Monarch Population Status
——————————————————

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/

——————————————————
4. Monarch Tag Recoveries from Mexico
——————————————————

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!

——————————————————
5. When monarchs are like corn —by Chip Taylor
——————————————————

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/

——————————————————
6. New Project: Monarch Directional Flight
——————————————————

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/

——————————————————
7. 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.

Filed under Email Updates | Comments Off on Monarch Watch Update May 2022

Development of the 2022 monarch population so far

18 May 2022 | Author: Chip Taylor

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.

May 8, 2022

May 9, 2022

May 10, 2022

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.

YearTotalRevised Total>40N%
202230426519272.5
201826522612153.5
201243536333492.0

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.

Filed under Monarch Population Status | Comments Off on Development of the 2022 monarch population so far