“Monarch River” at Cerro Pelon

Monday, January 21st, 2008 at 8:26 pm by Monarch Watch
Filed under Mexico, Monarch Migration | 8 Comments »

Last October, our tagging program was featured in an ABC World News segment (”A Nation on Monarch Watch“). This segment utilized some of my footage (shot in March, 2007) of streaming monarchs at Cerro Pelon in central Mexico. To stand in the “river” of tens of thousands of monarchs as they race down the ravines from the colony at Cerro Pelon on their daily quest for water is one of the most amazing natural phenomena I’ve ever had the privilege to experience.

Monarchs “streaming” at Cerro Pelon. Photo by Chip Taylor.

Movement of monarchs from the colonies to sources of moisture occurs on most warm days during the overwintering period from November through late March. Relative to the total population, the proportion of monarchs engaged in this activity is modest until mid February when the search for water intensifies. From that point onward monarchs “streaming” down from the colonies to moisture sources becomes a common sight. At Cerro Pelon, the butterflies, in what I call the “Monarch River,” are so abundant that you can hear the light clatter of the wings as they rush past at 10-12 miles per hour. If you are standing in the right place (or the wrong one from the butterflies’ point of view) they bump into you frequently as they are going so fast that they can’t always avoid obstructions. The “streaming” starts at 9am on warm clear days, lasting until early afternoon. Once the butterflies have acquired the water they’ve sought, they begin to “stream” uphill at a more leisurely pace, usually taking a different route back to the colonies. The quest for water is frenetic and energetically demanding and seems to take priority over visiting flowers for a source of moisture. The streaming precedes the migration northward and it could help prepare the monarchs for the return migration. Although streaming can last for weeks, it is not clear how long individual butterflies participate in the daily traverses down and back up the mountain.

Video: Monarchs “streaming” at Cerro Pelon, 2007; 30 seconds.

Streaming could serve several functions. The overwintering butterflies are in reproductive diapause and have a low metabolism. This low metabolic rate is under hormonal control, a control that is broken when ambient temperatures increase causing the butterflies to become sexually active. The water seeking activity, with its rapid flight, certainly raises body temperature and could accelerate this process by activating the hormonal cascade that breaks diapause. Further, the water acquired is probably used to metabolize lipids into sugars for flight and to facilitate the development of the latent reproductive organs. At the time these changes are occurring, environmental information is acquired and processed by the monarchs - in a manner as yet unknown. It may be that a genetic cascade is initiated that up-regulates the expression of some genes while down-regulating other genes with the overall effect that the butterflies reacquire the behaviors, five months dormant, needed to migrate northward to reproduce and start the annual cycle once again. We have a lot to learn about this process.

How do the monarchs find water? We don’t really know, but if monarchs are like other insects whose water seeking has been studied, they probably have special receptors for water known as hygroreceptors. Whatever they use, it certainly works. On a Sunday in March near Macheros, the village that leads to Cerro Pelon monarch colony, while filming streaming and water seeking monarchs I noticed a man watering his front “lawn” (mostly dirt with a sparse head of grass). He watered for quite some time and, as each portion of the front yard was watered, monarchs began to settle. By the time he finished watering there were thousands of monarchs in the front yard. Shortly thereafter the first guests arrived for an afternoon party. As each guest walked across the yard to the front door hundreds and hundreds of monarchs took flight around them. It was a delightful sight and I’m sure the rising monarchs were the host’s gifts to his guests and that the water was an intentional gift to the monarchs.

Monarchs watering on moist grass. Photo by Chip Taylor.

Monarchs “streaming” down a ravine at Cerro Pelon. Photo by Chip Taylor.

Map showing the location of streaming monarchs. View Larger Map

Revised 06 Feb 2008.

2007: Unusual Migration & Hotter Than Normal Fall

Friday, January 18th, 2008 at 8:54 am by Monarch Watch
Filed under Monarch Migration | 3 Comments »

Tagging has shown that the timing and pace of the migration is generally quite predictable (see “Peak Migration Dates“). The pace of the migration was normal this year as the butterflies advanced from 50 degrees latitude in the north to about 40 degrees in the middle of the country – then the migration appeared to slow. The slowdown corresponded to a prolonged high-pressure system, with hot temperatures over the central portion of the country from late September through most of October.

As you know I’ve given myself the responsibility of trying to interpret monarch numbers on a year-round basis. This task is not difficult and most of the time I can articulate at least a general description of the relative size of the population and can usually explain why the numbers might be up or down. It’s pretty general stuff and subsequent events usually show that I’m not too far off the mark. There are challenges however, and this fall presented one such challenge. Monarch numbers appeared to be above normal once again in the east, although not as numerous as in 2006. Further, it was clear that the numbers of butterflies originating from the upper Midwest were greater than in 2006. Yet there were signs that the population coming through the central portion of the country was below the long-term average for this region.

The progression of the migration through both the central portion of the country and along the coast was unusual. In addition to a slowed migration as mentioned above, relatively low numbers of monarchs were reported from southern Minnesota through Oklahoma, with few exceptions. As this was happening, I was speculating that the monarchs were there but just weren’t being seen or reported. Due to the numbers of observers, much of the migration moves through the Midwest unreported in most years so this speculation seemed reasonable. The number of observers in Texas is much greater and I was expecting large numbers of monarchs to be reported as they moved through that state. It didn’t happen. In addition, the number of monarchs moving along the Gulf Coast from east Texas to Corpus Christi was one of the largest seen in decades.

Our understanding of what happened this fall was greatly enhanced by the efforts of Mike Quinn. Mike is an Invertebrate Biologist at Texas Parks & Wildlife and he has established a substantial network of professional and amateur naturalists that report monarch sightings during both the fall and spring migrations. Mike also marveled at the unusual nature of the monarch migration through Texas and the numerous observations and reports led him to post a summary of the sightings to Dplex-L, a Monarch Watch discussion list. Mike’s summary and analysis is represented below. The only note to add is that Monarch Watch received reports that large numbers of dead monarchs had washed ashore at Galveston and other locations along the coast or were seen flying over the Gulf, emphasizing the hazards of coastal travel.

Texas Fall Monarch Flyway Analysis
Texas Monarch Watch - Compiled by Mike Quinn

Each fall, the majority of Texas monarch sightings consistently fall into what we call the Central and Coastal Flyways.Central (and larger) Flyway is generally most active from early to late October.

Conversely, the Coastal Flyway is generally active from mid October to mid November.
Question, are these flyways “real” and if so, why are they not synchronized?

Recapping the fall 2007 monarch migration.
Monarchs start heading south in late August.

By the first week in October, monarchs start crossing the Red River
The monarch front appears somewhat asynchronous at this time.

By mid October, monarchs pour through the Central Flyway.
This major monarch migration corridor generally extends from I-35 to Midland.

During the third week of October, the monarch flow appears to shift to the southeast.
At this time, monarchs occupy portions of the Central and Coastal Flyways.

By the last week of October, monarchs are primarily restricted to the Coastal Flyway.
The Coastal Flyway is more variable that the Central Flyway and is generally active from mid October to mid November.

The relative lack of monarch watchers across the southeastern U.S. contributes to the mystery of the origin of the coastal monarchs, but they likely started in the northeast.

If so, then the greater distance traveled from the northeast might account for the asynchronous timing of the Coastal Flyway, versus monarchs traveling a shorter distance from the Midwest and using the Central Flyway.

If the Coastal Flyway is populated by monarchs originating from the northeast, a potentially significant contributing factor to the delayed flight along this flyway may be the fact that winds rarely blow from the NE to the SW. Therefore, butterflies traveling such a route would encounter more cross winds than monarchs flying through the central flyway.

Some monarchs overwinter along the Gulf Coast. Is it possible that the impetus to continue migrating is lost due to the lateness of their arrival?

Concentrations of monarchs (shown in blue) seen along the Gulf Coast of Texas in late October 2007:

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Monarch Roost map graphics created using Journey North’s Fall 2007 Monarch Roost Maps

Roundup-Ready Crops and Resistant Weeds

Thursday, January 17th, 2008 at 2:31 pm by Monarch Watch
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One of our justifications for the Monarch Waystation program has been the loss of milkweeds in 100 million acres of row crops* that followed the adoption of Roundup Ready soybeans and corn. In June of 2004 I wrote “Effects of Transgenic Crops on Milkweeds” where I drew attention to this issue and to the rapid development of weeds resistant to Roundup (glyphosate) in Argentina and concluded “Roundup resistant weeds seem to be in our future.” They are here and are spreading rapidly.

Weeds resistant to Roundup are showing up in many areas of the United States. On the 20th of August 2007 National Public Radio aired a report on this topic by Dan Charles (“Farmers Switch Course in Battle Against Weeds”).

When I wrote the June 2004 article, 15 weed species in Argentina were notably resistant to Roundup. According to Dan Charles’s report there are already 13 Roundup resistant species in the United States. We are catching up fast.

Curiously, the use of Roundup is changing the composition of weed communities due to selection that favors species that are naturally resistant to Roundup such as lambsquarters, velvetleaf, giant ragweed, and Asiatic dayflower. Other species, with genetic variants that are resistant to Roundup, are increasing as well. This scenario may apply to wild parsnip, pokeweed, evening primrose, and horseweed - species that are showing up in row crops, a habitat in which they had previously been relatively uncommon.

*Note: Genetically modified seeds for major crops are now the rule, not the exception. In 2007, 92 million acres of corn were planted and of these 61% had been genetically engineered to express Bt toxins to kill or inhibit several types of insects, to resist Roundup, or both. Of the 64 million acres of soybeans planted in 2007, 91% were Roundup Ready. Due to the soy/corn rotation, my interpretation is that we’ve lost at least 100 million acres of milkweeds in these row crops since the first Roundup Ready plants were brought into production in 1996. This is an increase from my earlier estimate of a loss of milkweeds in 80 million acres of row crops. If you find milkweeds in corn or soybean fields, take a picture - it’s now a rare sight.

1,800 Monarch Waystations and Counting

Thursday, January 17th, 2008 at 2:01 pm by Monarch Watch
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The number of certified Monarch Waystations continues to grow. In 2007, we added nearly 800 habitats to the registry and the total number of registered Monarch Waystations to date is 1,835. We hope to add another 1,000 (or more!) habitats to the Monarch Waystation Registry in 2008 but we need your help!

The growth of the Monarch Waystation Program is clearly dependent on publicity but the publicity has to be at the right time and right place. One year we placed an advertisement promoting Monarch Waystations in a magazine for birders. The cost was not insignificant. Although the publication has a good circulation, the response was very weak. Given this experience and our extremely limited budget, advertising is out of the question and we have to rely on articles about our program in newspapers and magazines to get our message to the public. Last February an article on our program and Monarch Waystations appeared the gardening section of the San Francisco Chronicle:

“Gardeners save the day as butterfly habitats disappear”

The response to this article was overwhelming and in a matter of a few days we had orders for over 1,000 California Monarch Waystation Seed Kits. Articles in Midwest Living, Mother Earth News (”Relief for Weary Monarch Butterflies“) and the Chicago Tribune also generated good responses. However, we can’t count on the media to inform the public of this program every year so we are asking all of you to help spread the word. A number of people with Monarch Waystations have helped promote the program through contributions to online forums and through blogs. Others hand out literature at public events and during educational programs. Bob Morton (Monarch Waystation #613) has a sidewalk garden where he displays the Monarch Waystation sign to which he has attached a “take” box containing brochures describing the value of creating habitats for monarchs. All of these methods are great ways to get the public’s attention. Please help us spread the word!

Our special thanks to all who have participated in this program. We appreciate your continued support of Monarch Watch and monarch conservation.

New Website for Western Monarchs

Thursday, January 17th, 2008 at 1:32 pm by Monarch Watch
Filed under Western Monarchs | 4 Comments »

The Ventana Wildlife Society, under the leadership of Jessica Griffith and with the support of Helen Johnson, has created a website for Western Monarchs:

ventanaws.org/conservation/monarchs.htm

Much of the content of the website focuses on the efforts by the society, with the help of volunteers, to monitor the monarch overwintering locations in Monterey County, California.

2007 Monarch Tagging

Thursday, January 10th, 2008 at 10:30 am by Monarch Watch
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The number of orders for monarch tagging kits this past fall (1,800+) suggests that more people participated in tagging in 2007 than in any previous year. Moreover, the returned datasheets indicate that the tagging was quite successful overall. Most taggers returned their datasheets and unused tags by the 1st of December as we requested; if you still have your datasheet(s), please make copies and send us the originals as soon as possible so the data can be entered into our tagging database. Thank you for your cooperation!

Monarch Degree Days

Wednesday, January 9th, 2008 at 11:03 pm by Monarch Watch
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For the last four years we have been using the accumulated monarch degree days during the breeding season to show how the temperatures relate to the numbers of monarchs each fall. These records were particularly useful in explaining the low numbers of monarchs at the overwintering sites in the winter of 2004-2005. Although cooler in Texas and about average in the most northern portion of the breeding area, the summer of 2007 was the hottest among the last 5 years in the Midwest.

The total monarch degree days and potential number of generations for each of the last 5 years are summarized in the following table.

Table. Monarch degree day totals and potential number of generations through 23 September for 2003 - 2007.

Year	Dallas, TX	Lawrence, KS	Des Moines, IA	St. Paul, MN	Winnipeg, MB
2003	4511.0 (6.3)	3003.9 (4.2)	2626.3 (3.6)	2160.6 (3.0)	1508.1 (2.1)
2004	4458.3 (6.2)	2863.9 (4.0)	2391.5 (3.3)	1856.2 (2.6)	996.8 (1.4)
2005	4783.8 (6.6)	3180.3 (4.4)	2866.0 (4.0)	2250.7 (3.1)	1351.0 (1.9)
2006	4854.5 (6.7)	3007.8 (4.2)	2797.3 (3.9)	2394.9 (3.3)	1700.9 (2.4)
2007	4476.1 (6.2)	3417.8 (4.7)	2841.9 (3.9)	2450.7 (3.4)	1464.8 (2.0)

The methods used to calculate monarch degree days can be found in the “Monarchs, Cold Summers, Jet Streams, Volcanoes, and More” article from the Monarch Watch January 2005 Update. The breeding seasons of 2006 and 2007 have been the hottest, with the greatest number of potential monarch generations, of this period. Higher temperatures can favor monarch population growth but they can also be detrimental if they co-occur with drought conditions. The summer of 2004 was the coldest during this period and the coldest since the Mount Pinatubo summer of 1992. The low temperatures during the 2004 breeding season, one that followed massive mortality at the overwintering sites in January and February 2004 and high temperatures in March in Texas, contributed to the lowest overwintering population (2.2 hectares) observed or measured at the overwintering sites. The January 2005 Update article (referenced above) contains an extensive discussion of the factors that contribute to summer temperatures.

Monarch Population Status

Monday, January 7th, 2008 at 3:00 pm by Monarch Watch
Filed under Monarch Population Status | 2 Comments »

The monarch population in the eastern part of the breeding range was higher than normal for the second year in a row. Although the 2007 fall migration was smaller than normal in the upper mid-west, perhaps due to a mid to late season drought, the region was more productive than 2006. My expectation is that the overwintering population in Mexico will be 5-6 hectares* or a bit below the 5.9 and 6.9 hectares recorded the last two years, respectively.

Each year I predict the size of the overwintering monarch population in Mexico. My predictions are based on 15 years of experience, reports generated throughout the country, evidence of the success of our taggers, and a bit of intuition. In late September, in response to inquiries from the press, I estimated that the overwintering population in Mexico would be 7.5-8 hectares. I made this prediction before monarchs reached Texas and without consulting the population models I’ve been working on from time to time over the last several years. By mid October it became clear that this estimate was too high and I reduced the expectation to 5-6 hectares. The lower prediction is based on the sparse number of reports of large clusters of monarchs along the migration, a lower number of monarchs than expected (based on reports from observers) from the northeast as reflected in the Cape May counts and the apparent lateness of the migration from Kansas to the Mexican border.

In October I analyzed climatic data and overwintering numbers of monarchs for the last 14 years. This analysis showed that lower than expected numbers were measured at the overwintering sites following fall weather patterns similar to those seen this year. The population model I’ve developed is quite crude at the moment but it still may have some utility. The summer portion of the model predicts a winter population of 6 hectares for the winter of 2007-2008. However, the portion of the model that includes the fall conditions suggest a lower number will be measured when all the counting is done, perhaps around 5 hectares. The overall model is conservative and tends to not give the butterflies much credit for adapting to local conditions. So, while the fall data predicts a population of about 5 hectares, I’m expecting a number closer to 6 hectares. Let’s hope that both predictions are wrong and that my earlier seat of the pants estimate of 7.5-8 hectares was correct.

Last year, without using the model, I predicted that the overwintering population would be 6.5 hectares. The final tally, as measured by Eduardo Rendon and his crew from World Wildlife Fund Mexico (WWFMX), was 6.67 hectares. The total is a bit larger (6.9) if we include a small colony on Cerro Pelon (not measured by WWFMX) that was killed by a winter storm.

*NOTE: Monarchs are measured in hectares. Prior to 2002 we used estimates of 10-12 million monarchs per hectare based on earlier studies by Calvert and Brower. Surveys of the numbers of dead butterflies in two colonies following the winter storm that occurred in January of 2002, in which an estimated 80% of the monarch population died, produced strikingly different results (Brower, et al. 2004). Twenty-nine 0.05 square meter plots were sampled at each site, yielding an estimate of 2,680 monarchs per square meter at Zapatero (Sierra Chincua) and 7,253 monarchs per square meter at Conejos (El Rosario). This translates to 26,280,000 and 72,530,000 monarchs per hectare respectively. If we assume that these data represent only 80% of the monarchs that occupied each site, both numbers would be even higher. But, what can we do with these data? Technically, there are only two data points and they differ widely. We could use an average of the two, 49,400,000 or 61,750,000 if we assume 20% survived. However, we don’t know how evenly monarchs are distributed in the forests among all the overwintering sites. Are the high or low densities, as represented by theses two sites, the exception or the norm? We don’t know. Although it is clear that the number of monarchs is greater than 10-12 million per hectare, until we have more information on the tree and monarch densities at all sites, my preference is to measure monarch populations in hectares. Whatever the mean density, I’m able to make reasonably good predictions of the numbers of hectares of monarchs prior to the measures of the overwintering colonies.

Brower, L. P., Kust, D. R., Rendon-Salinas, E., Garcia-Serrano, E., Kust, K.R., Miller, J., Fernandez del Rey, C., and K. Pape. 2004. Catastrophic winter storm mortality of monarch butterflies in Mexico during January 2002. In The Monarch Butterfly: Biology and Conservation. Eds. Oberhauser, K. S. and M. J. Solensky. Cornell, Ithaca. pp151-166.

Maybe it DOES grow on trees after all…

Wednesday, January 2nd, 2008 at 6:44 am by Jim
Filed under General | 6 Comments »

A big THANK YOU goes out to the anonymous donor that delivered a wonderful end-of-year surprise to us here at Monarch Watch last week:

Yep, our very own money tree (no, not Pachira aquatica). We’ve harvested the 2007 crop (a whopping twenty “Grants” in all!) and hope our green thumbs can encourage this little plant to continue to produce its fortunate fruit…

We’ll do our best, but if you’d like to help us out with a donation of your own you’ll find all of the information you need here:

Give in Support of Monarch Watch

We appreciate donations of any amount - they are fully tax-deductible and 100% of your gift will help support Monarch Watch’s education, conservation, and research efforts.

Thank You!

Happy New Year!

Tuesday, January 1st, 2008 at 12:01 am by Jim
Filed under General | 3 Comments »

Greetings and salutations Monarch Watchers! A new year is underway and we are planning some big changes for Monarch Watch in 2008. To kick things off, we’re launching this blog which will allow us to distribute up-to-date information in an efficient, flexible, and timely manner. Here you’ll find all of the information previously reserved for our “monthly” email updates plus a whole lot more!

We’ll have lots more to say about this as we tweak the blog in the weeks and months ahead. As always, we welcome your comments and suggestions along the way - if you’d like to provide feedback please do so via our online community forums (there’s a “suggestions and comments” forum set up for just this type of communication).

Here’s to a GREAT 2008 for us all and thank you for your continued support!