New Website for Western Monarchs

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

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

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.

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

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…

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!

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!

Blog on the Launch Pad

We’re counting down to the launch of the official Monarch Watch Blog – blastoff is scheduled for 12:01am on January 1, 2008. Stay tuned!

PHOTO CREDIT: National Aeronautics and Space Administration (KSC-07PD-2923)

Updates From Mexico

Earlier I projected that there could be as many as 80-100 million monarchs at the overwintering sites this winter, up from the all-time low of 28.3 million of last winter. We won’t know how this estimate compares with the actual number of overwintering butterflies until mid-winter after Eligio Garcia completes his survey of the sizes of the overwintering colonies. For more information see “Mexicans predict banner year for monarchs” [dead link]

Here is another positive story: In a recent speech, Mexican President Vincente Fox devoted his attentions to the broad-based efforts to support preservation of the monarch overwintering sites. The text indicates a strong awareness of the issues and a concerted plan by the Mexican government to address monarch conservation. For a full text of this in Spanish please see

dailynews.yahoo.com/h/ap/20011128/wl/mexico_butterflies_1.html [dead link]

We will try to obtain an English translation of this text which we will post to Dplex-L and add to our website.

Where Are They Now/Late Monarchs

We have been told over the years that the last of the monarchs that overwinter in Mexico arrive at the colony sites during the first week of December. This may in fact be the case. However, as I sat down to write this we received a call from Kentucky with a report of a sighting today. Last week there were a least 5 reports of late monarchs and there was one report from the Dallas area of large numbers of monarch larvae being found on milkweeds in butterfly gardens.

The exceptional number of late sightings appears to be due to the northern position of the jet stream which has resulted in an unusually warm fall for most of the central and eastern United States. The first two weeks in November were the warmest ever recorded for eastern Kansas. We are not certain whether any of these late monarchs are still migratory or have any chance of reaching the overwintering sites in Mexico. These observations seem to indicate that there may be a number of late monarchs each year which are usually killed as the jet stream dips southward east of the Rockies in October.

Adopt-a-Classroom

As part of our Adopt-a-Classroom program, Monarch Watch delivers school supplies and textbooks annually to students in rural schools near the monarch reserves. We will leave for Mexico in early January with a van-load of supplies and will spend a week delivering the much-needed supplies to at least thirty schools in the area. Thank you to everyone who contributed financially or by mailing in school supplies!

We have textbooks!

At the end of each school year, certain textbooks are no longer part of the curriculum. Some of these books have never been used. These out-of-adoption textbooks are then returned to the publisher or the state textbook depository where they are either recycled or destroyed!

Thanks to the help of a few school districts in southern Texas, we have collected hundreds of new Spanish edition math consumables for grades K-2. We also have Spanish editions of science and health textbooks. We met with several textbook coordinators at these schools to learn about the textbook adoption process. Everyone we met was eager to help the students in Mexico; we all agreed that it is better to put these materials to good use rather than recycle them!