Monarch Watch Blog

Commentary: Recent Petition to Protect the Monarch Butterfly

2 September 2014 | Author: Chip Taylor

On August 26th 2014, The Center for Biological Diversity, Center for Food Safety, The Xerces Society, and Dr. Lincoln Brower submitted a petition to the Secretary of the Interior and the Fish and Wildlife Service requesting that the monarch butterfly be granted threatened status under the provisions of the Endangered Species Act. The petition is quite thorough (159 pages) and details evidence of the decline in monarch numbers, the numerous causes for the decline and the large number of threats to the population due to natural (parasites and predators) and human related causes ranging from pesticides to climate change. It’s an excellent summary of information those of us interested in monarchs should be familiar with. The full petition can be found at xerces.org/wp-content/uploads/2014/08/monarch-esa-petition.pdf

The petition has generated a great deal of discussion via social media, our discussion list (Dplex-L) and among groups as diverse as collectors, amateur butterfly enthusiasts and commercial butterfly breeders. There is a great deal of concern as to how threatened status would affect how we all interact with monarchs whether it would be through collecting, rearing, tagging or various forms of monitoring. These concerns are heightened by the presumption that a decision on this petition could happen soon. Further, there is some confusion about the terminology and process involved in designating a species as endangered or threatened.

The following paragraphs are intended to help clarify some of the issues associated with the petition.

Terminology
We need to be clear on the terminology.

“An ‘endangered species’ is one that is in danger of extinction throughout all or a significant portion of its range. A ‘threatened species’ is one that is likely to become endangered in the foreseeable future throughout all or a significant portion of its range.” (fws.gov/endangered/esa-library/pdf/listing.pdf).

Monarchs clearly aren’t endangered. This petition requests threatened status for the monarch based on the presumption that the monarch migration is threatened due to the loss of a significant portion of its breeding range in the upper Midwest, i.e. the corn belt. But, is it? That’s a matter of evidence and interpretation. As this discussion proceeds, we need to make it clear in all communications that it’s about the migration and not the species per se.

Process
The Fish and Wildlife Service has 90 days to respond to the petition. It’s likely they will accept the petition for further evaluation and will set a date for a public comment period that will start in about 15 months. This will be followed by further evaluation, perhaps requests for additional data, etc. Most of these petitions require lengthy reviews and revisions. Due to the large number of petitions for threatened and endangered status for a wide range of plants and animals, the significant number of high priority cases under consideration and personnel limitations at Fish and Wildlife, it could be many years, 5 at a minimum, possibly 10 or more, unless the monarch decline accelerates, before a determination is made as to whether monarchs are deserving of threatened status.

A schematic of the process can be found at fws.gov/endangered/what-we-do/listing-petition-process.html

petition process

A key statement is the following:
“A positive one-year finding can be incorporated into a proposed listing or, if a prompt proposal is precluded by other listing activities, the proposal may be deferred. These ‘warranted but precluded’ proposals require subsequent one-year findings on each succeeding anniversary of the petition until either a proposal is undertaken or a ‘not warranted’ finding is made.”

My understanding is that most proposals of this type are repeatedly deferred – some for as long as 20 years.

Outcomes
Petitions of this sort can have both positive and negative consequences. On the positive side, they tend to rally the advocates, draw broader attention to real conservation problems and attract funding that can help mitigate the problem. On the other hand, private landowners and other groups that have an interest in the status quo often challenge such proposed conservation measures. The fear of regulation, or the possibility of the government telling landowners what they can and can’t do with their land, rallies the opposition. This polarization can become political. There are a number of ongoing battles along these lines. Monarch conservation needs to remain apolitical and will be best served if we engage landowners rather than drive them away. The petition ends with a request for critical habitat designation (p 113). With statements such as “Of equal or more importance is the determination of the habitat necessary for that species’ continued existence… If the protection of endangered and threatened species depends in large measure on the preservation of the species’ habitat, then the ultimate effectiveness of the Endangered Species Act will depend on the designation of critical habitat.” H. Rep. No. 94-887 at 3 (1976).” But nowhere in this section, or elsewhere, is it clear what critical habitat means in the case of monarch butterflies or how it might be designated and protected. Designations of critical habitat in this case will have to be carefully crafted to avoid a backlash from landowners.

Habitat restoration
It is clear, as we have pointed out many times, that the monarch population is in decline due to loss of habitat. The petition is all about protection and covers habitat loss in great detail. However, protection alone will not stop the decline in monarch numbers. Unless we collectively address the annual loss of habitat with a significant recovery plan that restores at least 1-1.5 million acres of milkweed/monarch habitat per year – the eastern monarch migration will dwindle further to the point where it will be truly threatened. It’s been evident for some time that, petition or not, we have to restore habitats for monarchs. (monarchwatch.org/blog/2014/03/monarch-butterfly-recovery-plan/).

Monarch Watch is engaged with a large number of colleagues in discussions about how to provide more habitat for monarchs. The White House supports these initiatives through the Presidential Memorandum of 20 June. We are making progress with these discussions, and the goal is to implement broader conservation measures by next spring. If we (the monarch community in general) can create the needed partnerships and collaborations and obtain significant funding, the monarch migration can be saved. Saving the monarch migration is one of the easier conservation challenges we face. Let’s do it!

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Monarch Population Status

29 July 2014 | Author: Chip Taylor

Those of you who follow monarchs closely are aware that the monarch population has been declining for the last 10 years with significant drops in the population each of the last three years. The number of trees and total area occupied by monarchs in the oyamel fir forests in Mexico was at an all time low last winter – a mere 0.67 hectares. This decline has given rise to a great deal of concern about the future of the monarch migration. These concerns have resulted in many meetings and plans, and even a Presidential Memorandum directing federal agencies to devote resources to offset the decline in monarchs and pollinators. We have addressed this issue through our Monarch Waystation, Bring Back the Monarchs and Milkweed Market programs. These programs are growing but they need to become much, much larger to sustain the monarch migration. Large-scale habitat restoration, particularly in the upper Midwest, also needs to become a priority. In the meantime, we need to keep tagging monarchs as a way of monitoring their numbers and tracking any shifts in the origins of monarchs that reach Mexico. If you are a long-term tagger, you know it has been increasingly difficult to find enough monarchs to tag, especially during the last two years. The totals tagged each year roughly parallel the numbers recorded in Mexico each winter, giving us an independent assessment of the numbers in the migration. Regional tagging success also helps in that it demonstrates how monarchs respond to the physical conditions and quality of the habitats in these areas. Thus, tagging is an important tool to help us understand the overall dynamics of the monarch population.

So what should we expect this year? I usually like to wait until August to make predictions about the numbers in the migration and avoid bold assertions about the size of the overwintering population until well into the migration. However, this year I’m on record as early as the 3rd of May on our discussion list Dplex-L as predicting that there will be a modest increase in the number of monarchs in the migration and at the overwintering sites this winter. “Modest increase” is a vague term and I can’t put a number to it; however, all of the factors I’ve researched indicate that there will be more monarchs migrating this fall and at the overwintering locations by mid December when the colonies are measured. All in all things are looking up for monarchs this year.

Here is a brief overview of factors supporting my prediction of a modest increase in the number of monarchs this fall:

1. I looked at reports from those visiting the overwintering sites about the mortality seen at the colony locations. I also watched the weather in Mexico to be sure that there were no unusual weather events at the overwintering sites that would contribute to mortality. Fortunately, though the population was low, it seemed to winter well.

2. I followed the first sightings reported to Journey North and monitored, as closely as I could, the conditions of the milkweed and flowering of nectar sources in Texas. Since lower than normal temperatures in Texas in March and early April are also associated with an increase in the population, I monitored the temperatures in the region as well. Again, all the signs pointed to a slight growth in the population.

3. The temperatures during May and early June are another key to population growth. These temperatures largely determine when the first generation monarchs coming out of Texas and Oklahoma will reach the northern breeding area. Past records have shown that the timing of arrival of these monarchs in the north (i.e., >40N) is also critical. First sightings suggested fair numbers arrived during the critical period in the upper Midwest, smaller numbers arrived later in MI, OH and ONT and, still later, even fewer reaching the New England area. All of which suggested that most of the increase would come from the upper Midwest assuming that summer temperatures were normal or above normal.

4. A look at the longer-term temperatures suggested that normal temperatures could be expected over most of the northern breeding area, further supporting my optimistic outlook through May and early June.

5. The reports so far this July have not been disappointing. The 4th of July butterfly counts supported by the North American Butterfly Association, and other counts, have generally reported better numbers of monarchs in their surveys than last year.

Good luck with your tagging and thanks to everyone that participates in our programs!

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Milkweed inventory – plants remaining

27 May 2014 | Author: Monarch Watch

Although we have been shipping milkweeds like crazy – about 30K so far – we still have a few – actually quite a few (22K)- plugs left that are well rooted and ready to ship. We need to find homes for these plants. The attached spread sheet shows the ecoregions from which the seeds originated and to which we will send the plants. We use the Bailey Ecoregions as a guide. We have been advised to use these ecoregions to return plants to the zones to which they are best adapted. When we can, we return the plants to the same state as the seeds originated from though the ecoregion may span several states – e.g. 251.

ecoregions

R. G. Bailey, Ecoregions of the United States, USDA Forest Service, revised 1994.

Please pass this around. Due to a number of miscalculations and just the shear confusion of trying to keep track of the successful production from 112 different seed lots – which in most cases was higher than anticipated, we ended up with more plugs than we expected.

Thanks for any help you can provide. The flats with plugs (N=32) are available for $60.80 each through the Milkweed Market. Shipping is included for most locations but we are finding it necsssary to expedite the shipping (with associated higher costs) to areas where the temperatures are above 90F at this time of year. (Heat damaged plants aren’t pretty).

If you are interested in plants from California, A fascicularis is still available. Again, please send an email to milkweed@monarchwatch.org indicating your interest in these plants.

For additional information please visit our Milkweed Market

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Monarch Butterfly Recovery Plan

25 March 2014 | Author: Chip Taylor

The following is a memo outlining a recovery plan for monarch butterflies. On 1 March I received an email from a person well connected with monarchs asking me to prepare a document, a prospectus or memo, for business leaders by the end of the day. I was told that these persons needed background information about the monarch population along with a rough idea of what would be required to address the loss of milkweed/monarch habitat. The memo was prepared in haste and is not inclusive of all the components needed to successfully stabilize and then increase the milkweed habitats that support the monarch population. Nevertheless, this document outlines some of the basic issues. Hopefully these ideas will be useful in shaping the conversations needed to create a vision and plan as to how best to restore the monarch population. The original memo has been rewritten to improve clarity. An explanation of the estimated annual loss of habitat has been added as well.

MONARCH BUTTERFLY RECOVERY PLAN*

ORLEY R. “CHIP” TAYLOR
DIRECTOR
MONARCH WATCH
UNIVERSITY OF KANSAS
LAWRENCE, KANSAS
chip@ku.edu
1 March 2014

Introduction
The following text is a brief summary of the status of the monarch butterfly population. The reasons for the rapid decline in monarch numbers are discussed along with a proposed recovery plan. Recovery will be possible if 1) plans can be implemented to offset the annual losses of milkweed due to development and the expansion of croplands and 2) significant efforts are made to maintain the milkweed corridor that sustains the vast majority of monarchs that reach the overwintering sites in Mexico.

A declining population
The number of hectares of forest occupied by overwintering monarch populations in the Monarch Butterfly Biosphere Reserve (and neighboring sites) in Mexico is shown in Figure 1 below. The forest area occupied by monarchs for 2013-2014 is the lowest recorded to date and continues the progression toward smaller winter numbers seen over the last decade. The decline has been attributed to three main factors: 1) the widespread adoption of herbicide tolerant corn and soybean varieties by North American farmers which has had the effect of eliminating milkweeds (the host plants for monarchs) within the crop fields; 2) the ethanol mandate passed by Congress in 2007 that increased the price of corn and soybeans which in turn led to the conversion of grasslands to crops thus elimination of the milkweeds that occurred in these areas; and 3) three consecutive years during which the reproductive success of the summer breeding population was limited by unfavorable weather conditions. The loss of habitat, i.e. milkweed and nectar plants that sustain the monarch population, is massive yet can be mitigated. In the paragraphs below I will briefly outline a vision and goals for monarch recovery and will describe the infrastructure, resources and partnerships needed to implement this recovery plan.

monarch-population-figure-2014-monarchwatch
Figure 1. Total area occupied by monarch colonies at overwintering sites in Mexico.

Spring and summer breeding
Although monarchs can be found throughout the United States and southern Canada in the summer months, the main part of the population utilizes two critical areas with milkweeds: 1) the spring breeding area shown in Figure 2 below which encompasses most of Texas, Oklahoma, and part of Arkansas and Kansas; and 2) the upper Midwest (the eastern Dakotas, Minnesota, Wisconsin, Iowa, Illinois, Michigan and parts of Indiana). Monarchs arriving in the southern area from Mexico (in March) lay eggs on milkweeds, and the adults that develop as a result of this reproduction move northward into the summer breeding range in May and early June. This northward moving first generation spreads out over the north from the Dakotas to the Maritime Provinces in Canada. However, it is the production of the monarchs in the center of the “corn belt” that is critical. Our tagging data over the last 20 years and an earlier study using isotopes (Hobson and Wassenaar 1998, Wassenaar, et al. 1999) have shown that most of the monarchs reaching the overwintering locations in Mexico originate from this region.

monarch-population-figure-2014-monarchwatch
Figure 2. Spring and summer breeding areas in the milkweed/monarch corridor in relation to corn acreage planted in 2011.

The milkweed/monarch corridor
These two important areas of reproduction constitute what I call the milkweed/monarch corridor. Unfortunately, it is within this corridor that a large portion of the milkweed-containing habitat has been eliminated (Figure 3). Loss of habitat in this region is likely to continue which will lead to a further decline in monarch numbers.

monarch-population-figure-2014-monarchwatch
Figure 3. Areas of grasslands, shrub lands and wetlands converted to croplands 2008-2011. Increases in acreage by crop type are shown at the bottom of the figure. From Faber, et al. 2012.

Premise
The monarch population will continue to decline unless 1) the annual loss of habitat (.5 to 1.5 million acres**), due to conversion of landscapes to crops and development, is addressed and 2) large-scale restoration of milkweeds is initiated to offset the losses of habitat that have occurred over the last 15 years.

Vision and goals
The monarch migration can be saved if there is commitment to the two propositions outlined in the premise to 1) offset annual losses of habitat by planting milkweeds and nectar plants in areas from which they have been extirpated and 2) develop the capacity to plant milkweeds over large landscapes. Both projects require the development of greater capacity to restore milkweeds than exists at present.

Implementation
Implementation of this recovery plan will depend upon the development of many different components. The program will require: 1) marketing and outreach so as to engage citizens, agencies, corporations, institutions and farmers; 2) a means of identifying landscapes on which milkweeds can be restored such as Conservation Reserve Program (CRP) lands, private lands, roadsides, federal lands, state and local parks, marginal landscapes, corporate landscapes and buffer strips; 3) a program to develop partners who can contribute to the success of the program such as nurseries, seed growers and native plant societies; 4) participants who can help with the seed collecting and plantings such as children in 4H programs, Future Farmers of America (FFA), Scouts, schools and other environmental organizations; and 5) communications with Federal, State and Local authorities to facilitate these efforts.

Capacity building and time frame and costs
In my view, the capacity to offset annual losses of milkweed/monarch habitat doesn’t exist at this time. The production of milkweed seeds and plugs (small plants) needs to increase rapidly. In addition, outreach needs to be developed and partnerships formed to get the seeds and plugs planted. By moving rapidly to implement this plan, the means to offset annual habitat losses can be developed in three years, and by the fourth year it should be possible to address the habitat losses that have accumulated over the last 15 years. Offsetting the annual habitat loss will require the establishment of at least 5-15 million milkweeds via the planting of seeds and plugs. Given the need to develop the infrastructure – seed production, etc., mentioned above, my estimate is that the yearly budget for this program should be $xxxxx million***. If more funds are available, the project could be expedited.


*This memo details what might be done to restore the monarch population that breeds east of the Rocky Mountains.

**Annual loss of habitat. One result of the ethanol mandate of 2007 has been the conversion of 24 million acres of grassland, rangeland, wetlands and shrub lands to crops. The loss by county for 2008-2011, 23,681 million acres, is shown in Figure 2. An additional 400,000 acres were converted to crops in 2012 bringing the total to more than 24 million acres. Figures for the conversion of grasslands (much of it retired CRP land) to croplands for 2013 are not yet available. Although the rate of conversion to croplands may be slowing down, Congress has mandated a further reduction in the CRP program with a cap at 24 million acres by 2017. The bottom line is that milkweed-containing habitats within the farming sector will continue to decline but – by how much? Annual losses of .5-1.5 million acres are likely but these estimates are based on a number of assumptions as follows:
1) Conversion of grassland and retired CRP lands to croplands will continue at rates of 350-450 thousand acres per year.
2) Loss of habitat due to development will continue. The annual conversion of landscapes in the United States to building sites and the expansion of cities is in excess of 2 million acres per year. Much of this development, perhaps 500,000 acres, occurs in the monarch summer breeding range. Other losses, perhaps 100,000 acres per year, are occurring in monarchs’ spring breeding range.
3) Losses outside the corridor will continue and these losses will also have a negative impact on monarch numbers.
4) There are additional losses of milkweed/monarch habitats that are not easily accounted for such as land management decisions that eliminate milkweeds and other forbs from pasturelands, roadsides and other land parcels.
5) Lastly, this interpretation assumes that the price of corn will remain in the $4-$5/bu range. Higher prices are likely to result in the conversion of more milkweed containing habitats to croplands.

It should be clear that, although the figures for the annual loss of milkweed/monarch habitat are not firm, it is likely that these losses will be close to a million acres per year for the foreseeable future.

***I have not prepared budget for this project. As you can see from the above, capacity building and implementation are both complicated and will require a major effort from many participants. Suffice to say, the annual cost of this program will be many millions. The project needs to be refined more precisely before dollar figures can be assigned to the different cost centers.

References

Cropland conversion. 2014.
http://www.fsa.usda.gov/FSA/webapp?area=newsroom&subject=landing&topic=foi-er-fri-dtc (accessed 28 January 2014).

Faber, Scott, Soren Rundquist and Tim Male. 2012. Plowed Under: How Crop Subsidies Contribute to Massive Habitat Losses. Environmental Working Group http://static.ewg.org/pdf/plowed_under.pdf (accessed 28 January 2014).

Hobson, Keith A., Leonard I. Wassenaar and Orley R. Taylor. 1999.
Stable isotopes (dD and d13C) are geographic indicators of natal origins of monarch butterflies in eastern North America.
Oecologia (1999) 120:397±404.

Wassenaar LI, Hobson KA. 1998. Natal origins of migratory monarch butterflies at wintering colonies in Mexico: new iso- topic evidence. Proc Natl Acad Sci 95:15436±15439.

For further information about monarchs, milkweeds and Monarch Watch, please visit MonarchWatch.org.

Further commentary

Obviously, mitigating the decline in the monarch population will require a great deal of discussion. In the above I’ve only addressed what it might take to mitigate the annual losses of milkweed monarch habitat. The larger issue is how to restore sufficient habitat so that the overwintering monarch population will be large enough, and will survive in sufficient numbers to repopulate the milkweed/monarch corridor each year. There is a history of catastrophic mortality at the overwintering sites (70-80% losses due to winter storm in 2002 and 2004). The large overwintering populations of 2001-2002 (9.35ha) and 2003-2004 (11.12ha) survived in sufficient numbers to recover from these losses in two years. Overwintering populations of a hectare or less will not fare as well should they experience such mortality. The recovery would take much longer. How can the latter scenario be avoided? My interpretation is that – at a minimum – our larger target should be to provide sufficient milkweed/monarch habitat to sustain populations of 4 hectares or more from year to year. Even with high winter losses such populations should be robust enough to repopulate the United States in the spring.

There are more questions of course. What are the near and long term goals? How much will the project cost and where will the funds come from? Will public funds be available? Will corporations, foundations, environmental organizations and private individuals support this effort? How will the funds be administrated? Who are going to be the partners in this enterprise and who will take the lead in coordinating the implementation of this program?

There are lots of questions; monarchs need the answers.

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Monarch Population Status

29 January 2014 | Author: Chip Taylor

The overwintering numbers are in from Mexico and once again it’s bad news. The numbers are not a surprise; as early as May, we predicted that the population would be lower this winter. I’ll discuss our reasons for this expectation and the overall decline seen throughout the last decade, but first, let’s look at the numbers reported by World Wildlife Fund, Mexico.

monarch-population-figure-2014-monarchwatch
Figure 1. Total Area Occupied by Monarch Colonies at Overwintering Sites in Mexico

Habitat Loss

In previous postings to this Blog I’ve mentioned three factors that have contributed significantly to the loss of monarch and pollinator habitats: the adoption of herbicide tolerant (HT) crops, the ethanol mandate, and development. In my lectures I’ve presented figures in which I try to quantify the loss of habitat attributable to each of these factors. The expected low numbers of monarchs in Mexico this winter have caused me to reevaluate and clarify these losses. My interpretation is summarized in the two tables below. The loss of monarch habitat due to the adoption of HT crops and the ethanol mandate is summarized in Table 1. The overall loss of monarch habitat is shown in Table 2.

Let’s deal with the HT crops first.

Year Corn & Soy Acreage Event
1996 143.5 million First HT Crops
2006 153 million Before Ethanol
2007 158 million Ethanol Mandate
2012 169 million Conversion Continues
2013 174.4 million Conversion Continues
Bottom Line: 29.5 million more acres of C&S in 2013 than 1996. Of this acreage >24 million represent former CRP, grassland, rangeland, and wetland habitats.

Table 1. Loss of Monarch Habitat due to HT Crops and Biofuel Initiative

If you have been following postings to this Blog, you know that row crops (e.g., corn and soybeans) contained relatively small quantities of common milkweed when tillage was used to control weeds in these fields. Some milkweed survived and a survey conducted in 2000 (Oberhauser, et al 2000) showed this habitat to produce more monarchs per acre than other milkweed/monarch habitats. With the adoption of HT crop lines, the use of glyphosate has all but eliminated milkweeds from these habitats (Brower et al 2011, Brower et al 2012, Pleasants and Oberhauser 2012 and personal observations).

One of the startling aspects of the corn and soy dynamics is the increase in acreage over the last 17 years. In 1996 the total acreage for corn and soy was 143.5 million acres while in 2013 was 174.4 million acres – an increase of 29.5 million acres. Note that while the acreage increased by 9.5 million acres from 1996 to 2006, the acreage increased by 20 million over the last 7 years. This increase is largely due to the ethanol mandate. Early in 2007 congress passed the Clean Energy Act of 2007, frequently referred to as the ethanol mandate. It was apparent to many growers in the spring of 2007 that this act was going to increase the demand for and price of corn. Corn planting has been increasing ever since with the result that farmers have removed hedgerows and narrowed field margins. In much of the corn-belt, farming is from road to road with little habitat for any form of wildlife remaining. Grasslands – including some of the last remaining native prairies, rangelands, wetlands, and 11.2 million acres of Conservation Reserve Program (CRP) land – have been plowed under to produce more corn and soybeans. Most of these acres formerly contained milkweeds, monarchs, pollinators and other forms of wildlife. They are gone and the total loss of these habitats since 2008 exceeds 24 million acres (an area about equal to the state of Indiana).

Development consumes about a million acres of farmland a year and the conversion of woodlands and other landscapes to shopping malls, housing and roadways consumes another million acres a year. Overall, the loss of various habitats due to development probably exceeded 34 million acres since 1996. Some of this habitat was in the West and since we are just considering the eastern monarch population, I’m estimating the total loss due to development to be 17 million acres. Not all of these landscapes contained milkweeds but much of it did at one time. There are also habitat losses due to excessive mowing and use of herbicides along roadsides. In an earlier study (Taylor and Shields 2000) we showed that the area from the edge of the road to the edge of the field was about 1% of the total land area in most eastern states. These were significant milkweed and monarch habitats in the past but it appears that much of this habitat has been lost as well due to these practices. Unfortunately, there is no way to estimate this loss.

I’ve summarized the total loss of habitat in Table 2.

Factor Acres
HT corn & soybeans >150 million
Development +/- 17 million
Total >167 million*
*Represents >30% summer breeding area

Table 2. Habitat Loss

My conclusion is that at least 167 million acres of monarch habitat has been lost since 1996. Not all of the corn and soybean acreage occurs within the summer breeding range for monarchs so the total loss of monarch habitat due to HT crops is lower (150 million) than the total area (174.5 million) planted in 2013. The 24 million acres of grasslands, etc. converted to croplands since 2008 have been included in the estimated loss to HT crops. Add to this number the estimated loss due to development and the total is 167 million acres lost but this could easily be an underestimate since there are losses such as roadside management that we can’t account for. To give you some perspective on the area that is represented by this figure, consider the following: 167 million acres =261 thousand square miles – an area just below the total acreage of MN, WI, IA and Il (266 thousand square miles) and Texas (266 thousand square miles).

The total summer breeding range for monarchs is probably 800-900 thousand square miles. If it is true that 261 thousand square miles of this range no longer contains milkweeds and nectar plants for monarchs, it would mean that 29-33% of the monarch breeding range has been lost. This loss is calculated based on the entire summer breeding range. A more refined approach confined to the states and the region of southern Ontario that produce most of the monarchs that reach Mexico is likely to show that the loss in these areas is much higher. Have I overestimated these losses? Maybe – but probably not. In any case, due to the economic forces involving crop production and human population growth, these losses will continue. It is clear that if our goal is to save the monarch migration, we must find a way to mitigate the loss of monarch habitat.

Reproductive Success

In a long article posted to the Blog on the 29th of May 2013 (“Population Status“), I discussed the prospects for the development of the monarch population over the coming months. The article started as follows:

“Monarchs are off to a slow start this year, with the number moving north in May at an all time low (as indicated by first sightings reported to Journey North). In the following paragraphs I’ll explain why this will be a lean year for monarchs and why the overwintering population in Mexico could be even lower this coming winter than it was in 2012-2013. Predicting whether monarch populations will increase or decrease would seem to be risky or even foolish but, as you will see, there are patterns that support these predictions based on: 1) overwintering numbers; 2) first sightings in the spring (1997-2013); and 3) the impact of temperature on the development of the first generation immature stages and the ability of adult monarchs to move northward to recolonize the breeding areas in the northern states and Canada.”

The above was followed by a long explanation of the patterns of first sightings and comparisons of the numbers of first sightings and temperatures during the breeding season for other low years. I concluded with the following summary:

“So, what does this tell us about what to expect in the fall and winter of 2013? Let’s deal with the number of observations first. Although, the number of first sightings reported in 2013 is similar to those of 2004 and 2005, the number of people reporting first sightings has increased significantly since reporting of first sighting began in 1997 (Howard and Davis 2004). In other words, fewer monarchs have been seen this year by a larger group of observers – suggesting that the number of returning monarchs was lower in 2013 than in 2004 and 2005 (both low returning populations) or even 2010, which saw the lowest overwintering population (1.92 hectares) prior to that of this past winter.

There is a similarity between 2013 and 2004 – the monarchs will arrive late in the northern breeding areas. The mean temperatures for March (-2.0F) and April (-2.7F) were the lowest for these months since 1996 and the April temperatures in particular slowed development of immature stages. May temperatures – which in most of the South Region are near or just below normal – have not appreciably aided northward movement of first generation monarchs. The result of all of these factors is that the arriving number of first generation monarchs will be low and they will arrive late. Even if this projection is true, is there a chance that the population can rebound as it did in 2005? Yes, but the temperatures in nearly all of the northern breeding range will have to be above normal by 2-3F throughout the summer for the population to increase. If the temperatures are normal (and normal summer temperatures are projected by NOAA for the upper Midwest (see the National Weather Service’s Climate Prediction Center), the overwintering population is likely to be in the range of 1 hectare again this coming winter and could be much lower.”

As it turned out – all of the above came true. The monarchs did arrive late in the summer breeding areas. The number of arriving butterflies was also low. In the northeast temperatures favored nearly on time arrival of the colonizing butterflies but extensive periods of cool, rainy days limited reproductive success. The conditions were so poor for reproduction in the northeast that it became clear in August that the number of monarchs that would be recorded at Cape May, New Jersey, during the migration would be quite low and it was (third lowest recorded since 1992). NOAA was right on target with the temperature predictions too. Normal temperatures were experienced throughout the northern areas – not the higher than normal temperatures that were needed to increase the population. The delayed arrivals apparently resulted in a late migration at the end of the season. Throughout the fall we kept hearing how late the migration was. In Lawrence, KS we had some on time arrivals, a rather small number, followed by a bit of a delay and then a flush of late migrants. In a year with an early onset of freezing weather many of these migrants would not have survived. But it was a warm fall and they kept moving, arriving later than usual in the vicinity of the overwintering sites in Mexico.

Every year is unique but some years deviate more than others from the norm. 2012 and 2013 both deviated from normal with 2012 being too hot and 2013 being too cold at critical times, and both resulted in low overwintering numbers. We break the breeding season into three intervals: March-April, May- 9 June, and June-August. The temperatures in 2012 were higher in each of these intervals than for any of the last 18 years. In 2013 the temperatures were lower than normal for the first two periods. However, it was the lower than normal temperatures in April that slowed development of immatures, and somewhat cooler May and early June that delayed the recolonization of the summer breeding areas.

Monarch numbers will rebound but only if the weather allows AND there is enough milkweed to increase the population. While we will never get back to the large populations of the 1990s, there is still enough milkweed to produce monarchs in sufficient numbers to colonize 3-4 hectares of the forests in Mexico. However, given the current size of the overwintering population it is likely that it will take 2-3 years with relatively favorable breeding conditions for the population to attain such numbers.

Looking ahead, NOAA is predicting higher than normal temperatures for Texas in March and April – which wouldn’t be good. On the other hand, some of the weather services are projecting normal temperatures through mid-March. That sounds better to me. Let’s hope there are favorable conditions for monarchs over the next several years. While waiting for conditions to improve, let’s plant milkweed – lots and lots of it.

I wish to thank Vijay Barve, Janis Lentz, Elizabeth Howard for help determining the patterns described above and to Jim Lovett for his assistance on the figures and formatting of this Blog entry.

References

Brower, L.P., Taylor, O.R., Williams, E.H., Slayback, D.A., Zubieta, R.R. & Ramirez, M.I. (2011) Decline of monarch butterflies overwintering in Mexico: is the migratory phenomenon at risk? Insect Conservation and Diversity, 5(2): 95-100.

BROWER, L. P., TAYLOR, O. R., WILLIAMS, E. H. (2012) Response to Davis: choosing relevant evidence to assess monarch population trends. Insect Conservation and Diversity (2012) 5, 327–329.

Pleasants, J.M, Oberhauser K. S. (2012) Milkweed loss in agricultural fields due to herbicide use: Effect on the Monarch Butterfly population. Insect Conservation and Diversity (March 12, doi: 10.1111/j.1752-4598.2012.00196x)

Oberhauser, K.S., Prysby, M.D., Mattila, H.R., Stanley-Horn, D.E., Sears, M.K., Dively, G., Olson, E., Pleasants, J.M., Lam, W.F. & Hellmich, R. (2001) Temporal and spatial overlap between monarch larvae and corn pollen. Proceedings of the National Academy of Sciences USA, 98, 11913– 11918.

Taylor O R, Shields J. The Summer Breeding Habitat of Monarch Butterflies in Eastern North America. (2000) Washington, DC: Environ. Protection Agency.

Notes: The figure (24 million acres) for the conversion of grassland, rangeland, wetlands and former CRP lands to cropland was obtained from two sources: Faber, Rundquist and Male (2012) data obtained from a USDA website summarizing cropland conversion in 2012 (2013). The former showed that 23.6 million acres had been converted to cropland from 2008 through 2011 and the later indicated that 398,223 acres had been converted in 2012. No figures are yet available for these conversions in 2013.

Plowed Under: How Crop Subsidies Contribute to Massive Habitat Losses (2012)
Scott Faber, Soren Rundquist and Tim Male. Environmental Working Group http://static.ewg.org/pdf/plowed_under.pdf (accessed 28 January 2014).

CROPLAND CONVERSION http://www.fsa.usda.gov/FSA/webapp?area=newsroom&subject=landing&topic=foi-er-fri-dtc (accessed 28 January 2014).

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Importance of Monarch Conservation

24 January 2014 | Author: Monarch Watch

by Candy Sarikonda, Monarch Watch Conservation Specialist

I am a nurse. A mother. A lover of nature. I want to make this world a better place.

And monarchs are helping me do just that.

Monarch conservation is important for many reasons. First, conserving and creating monarch habitat will help many of our pollinators. Every third bite of food we eat comes to our table courtesy of a pollinator. Monarchs, bees and many other pollinators share much of the same habitat—so what happens to monarchs, happens to other pollinators. Monarchs are an indicator of the damage done to our environment—we can count them as they gather by the millions in Mexico. They are an indicator of what we cannot fully quantify—the loss of our pollinators and their habitat. We need to protect all of our pollinators—the many bees, birds, bats, and other insects that provide us with pollinator-services and ultimately put food on our table. Do you like blueberries, strawberries, raspberries? How about watermelon, apples, bananas or squash? Chocolate? Then thank a pollinator!

Monarchs are a flagship for conservation. The Monarch Joint Venture explains this well http://monarchjointventure.org/news-events/news/monarchs-as-a-flagship. Monarchs engage children and adults in conservation efforts. By participating in the monitoring of monarchs through citizen science programs, or simply experiencing the joy of raising a monarch at home or in school, children get direct experience with nature and develop the strong connection with nature that will lead to their development as conservationists of the future. According to the Nature Conservancy, conservationists point to a childhood experience with nature as the most important factor that led to their environmental activism as adults. In an increasingly urban society, we need to keep giving children direct experiences with nature that will foster their development into conservationists.

We know that exposure to the natural world can produce significant health benefits. Exposure to nature has been shown to decrease stress and anxiety, lower blood pressure, reduce obesity, reduce symptoms of Attention Deficit Hyperactivity Disorder, and promote a general sense of well-being. Citizens who understand the connection between themselves and the natural world understand the importance of caring for themselves and their environment. By participating in projects designed to monitor monarch populations, citizens can witness the effect that pesticides and loss of habitat have on pollinators. And they can see how the loss of pollinators ultimately affects them.

Monarch conservation can also help develop an interest in science. Engaging students in exploration and observation of the natural world will help them develop the skills critical for the development of our future science and technology leaders. In a global market, the U.S. cannot afford to lag behind many other industrialized nations in the preparedness of our students for careers in science, technology, engineering and math (STEM). We need to get our youth interested in science; to make it fun and exciting for them; and help them build the confidence they need to succeed in their chosen STEM career paths. Exposure to the natural world helps children develop social skills, improve critical thinking skills, develop self-initiative, develop self-confidence and improve creativity. These are the skills needed by successful STEM leaders of the future.

Each and every one of us must do our part in conservation of our natural world. Conserving the monarch migration is one way to make a difference. There are many ways to help monarch butterflies. We must create, conserve, and restore monarch habitat—we need to plant milkweed. And not just milkweed, but many other host and nectar plants that support our bees, butterflies, and birds. It is OUR responsibility to restore habitat. No one person can do it alone—it takes a village. If every person in this country planted just ONE milkweed, we would have 300 million more milkweed plants than we do now. It starts with education—educating people that monarchs are in decline; that they only feed on milkweed; and that we can collectively do something to help them. We need to make a conscious effort—educate ourselves, find out what monarchs and other pollinators in our home gardens and park preserves love, and plant it; instead of growing plants with no pollinator-value. We can reduce mowing of roadsides and other suitable plots of land, and demonstrate the cost savings. Eliminate needless lawn and plant pollinator-friendly plants. Get involved in citizen science programs. Be of service and volunteer.

We need to reduce pesticide and herbicide use. Pesticides kill insects, and can harm or kill monarchs. But they can also harm humans. According to the American Academy of Pediatrics, a growing body of evidence indicates the negative health outcomes that can arise from exposure to pesticides during childhood http://pediatrics.aappublications.org/content/130/6/e1765.full Scientists have noted the effect that pesticides and herbicides have had in animal models, and have documented evidence of their impact on human health in farming communities. We have seen increased rates of depression and Parkinson’s disease in farming communities. In California’s Central Valley, farming towns are referred to by some as “Parkinson’s Alley,” for their higher than average incidence of this debilitating neurological disease www.sierraclub.org/sierra/201201/parkinsons-pesticides.aspx Yet, with the advent of GM crops, we have seen an increase in the use of herbicides, the development of superweeds, and the use of more and more potent chemicals www.huffingtonpost.com/2012/10/04/pesticides-gmo-monsanto-round-resistance_n_1936598.html It is time to reexamine the way we farm, and how we use pesticides/herbicides in our daily lives. Clearly, limiting herbicide and pesticide use will not only be good for monarchs—it will be good for human health as well.

We need to contact our legislators and support legislation that protects pollinators and their habitat. The Farm Bill is an important piece of legislation that can be used to support the creation of pollinator habitat in the form of Conservation Reserve Program (CRP) land. We need to encourage our legislators to support provisions in the Farm Bill for the creation and maintenance of CRP land. According to the Ohio Department of Agriculture, over one billion bees, or nearly 75% of Ohio’s honeybees, have been lost to Colony Collapse Disorder. An untold number of native bees have been lost as well. Crops left unpollinated could result in over $80 million in lost revenue per year for Ohio’s specialty farmers alone. We must let our legislators know we support efforts to conserve pollinator habitat via the Farm Bill and other forms of legislation. We need to educate and empower our fellow citizens to do the same.

We need to work with the private sector, and encourage companies to adopt business practices that will conserve natural resources. We must convince companies that investing in “green capital” is not just the morally right thing to do—it is the only thing to do. Investing in our natural resources is a necessity for many companies to continue their business practices. http://www.youtube.com/watch?v=ZED8IZmjdWc According to Mark Tercek, CEO of the Nature Conservancy, nature is not a luxury—it is an investment.

As conservationists, we must focus on bringing newcomers to the conservation table, engaging the general public in our conservation efforts. We cannot continue to “preach to the choir.” Monarchs bring people to the table. No monarch conservation organization simply promotes monarchs only. Monarchs are the focus of course, but the ultimate goal is conservation—of both humans and wildlife.

In any endeavor, it is important that we all work together. We must focus on what unites us, rather than on what divides us. We will have different ideas, different experiences, and different viewpoints. But we must find common ground, and use our differences to make us stronger. It will take many hands to secure the future, both for the monarchs and ourselves. We must present a united front. This is something that partners in monarch conservation have known for years — Monarch Joint Venture partners united in one effort, ultimately to protect the environment and humanity.

How did we get from monarch conservation to the subject of pollinator habitat, human health, green capital and STEM rankings? It’s simple. Humans do not exist separately from nature. The term “The Web of Life” is not just a flowery cliché. It is reality. Everything is connected. Everything.

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A Bit of Monarch History

24 January 2014 | Author: Monarch Watch

by Ilse Gebhard, Monarch Watch Conservation Specialist

I recently received a folder labeled “National Butterfly” from a Kalamazoo Area Wild Ones member. He had found it while working on a project documenting the history of Michigan State University’s Kellogg Biological Station in Augusta, Michigan.

The contents of the folder covered an aspect of monarch history all new to me, as it occurred in 1989, about 10 years before I really became involved with monarchs and 3 years before the founding of Monarch Watch.

For its 100-year anniversary in 1989, the Entomological Society of America (ESA) decided that the country needed a National Insect and they voted the monarch as its choice, representing about 600 species of butterflies and at that time nearly 90,000 other insect species that are an integral part of the natural heritage of the United States. They were well aware, nearly 25 years ago, that monarchs were declining in numbers under pressure from urbanization and loss of habitat resulting in the reduction of milkweeds and overwintering groves of trees in California and Mexico.

ESA put out a very nice colored brochure covering monarch history, biology, migration, ecology, and conservation of overwintering sites. The brochure includes a very impressive list of sponsoring organizations:

• Entomological Society of America (ESA)
• American Registry of Professional Entomologists
• American Institute of Biological Sciences
• Connecticut Entomological Society
• Lepidopterist Society
• National Audubon Society
• National Wildlife Federation
• New York Entomological Society
• The Nature Conservancy
• The Wildlife Society
• Xerxes Society

In addition the folder contains letters of support from:

• Kentucky Academy of Science
• American Association of Zoological Parks and Aquariums
• The American Entomological Society (AES)
• Kansas Associated Garden Clubs, Inc.

The ESA apparently worked very hard to promote the monarch as National Insect. The contents of the folder (the brochure plus 9 pages) were a packet of info that they sent out to various organizations asking them and their members to support this endeavor. One such organization was the Kellogg Bird Sanctuary, as per cover letter in the folder.

To me the most interesting document in the folder is a copy of H.J. RES. 411, a Joint Resolution introduced into the House of Representatives on September 27, 1989 by Representative Leon Panetta from California. Representative Panetta was born in Monterey, a well-known overwintering site of the Western US monarch population, and was elected from his native district. It was referred to the Committee on Post Office and Civil Service and by January 31, 1990 it had nine cosponsors. Not having found any further info on the resolution by a web search, I assume it died for lack of cosponsors.

The above-mentioned letter of support from the Kentucky Academy of Science states that they will pursue the adoption of the monarch as the State Insect. I guess that was not to be either, as a web search shows the viceroy to be its State Insect adopted in 1990 – close, but not the real thing. On the other hand, the monarch is the State Insect of Alabama, Idaho, Illinois and Texas and the State Butterfly of Minnesota, Vermont and West Virginia. Interestingly, 15 states have the non-native honeybee as their State Insect, 1 state lists it as their State Bug, and 2 states list it as their State Agricultural Insect. Five states have neither a State Butterfly, Insect or Bug.

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North Florida Monarch Overwintering Count

24 January 2014 | Author: Monarch Watch

DO MONARCH BUTTERFLIES
OVERWINTER ALONG THE GULF COAST OF NORTHERN FLORIDA?
FINAL REPORT OF THE 2013 MONARCH OVERWINTERING COUNTS

Richard G. RuBino
August 2013

Summary: For years monarchs have been seen along the northern coast of the Gulf of Mexico during January and February, but few attempts to document these sightings have been made. In recognition of this need, a count was undertaken in January and February 2013 to determine the degree of overwintering, if any, along the coast of the eastern end of the Florida Panhandle. The project focused on two questions: do monarch butterflies overwinter along the northern Gulf coast and does milkweed survive northern Gulf coast winters? Sub-questions included: if so, where and at what intensities? The answer to both questions is yes — sometimes. The study found both monarchs and milkweed across the entire length of a four-county coastal area, but the survival of the former is highly dependent on the benevolence of mankind.

Full Text (19-page PDF file): FINAL REPORT OF THE 2013 MONARCH OVERWINTERING COUNTS

Map 1 (PDF file): Observed Locations of Milkweed in the Big Bend of Florida, January-February 2013

Map 2 (PDF file): Observed Locations of Monarchs in the Big Bend of Florida, January-February 2013

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Moving for Monarchs (M4M)

19 December 2013 | Author: Chip Taylor

“Moving For Monarchs” started with an email I received on the 20th of March. My inbox is flooded with emails, so many that I can’t answer them all (and to those of you that I haven’t gotten back to – I apologize). I make a special effort to try to get back to journalists in a timely manner and, when I received an email with the subject line “Hoping to speak with you”, I thought it might be from a journalist and I opened it. To my surprise, it was an offer to assist in publicizing the need for monarch conservation from a 21 year-old dancer, actor, and writer by the name of Gwynedd (pronounced Gwyneth) from New York City. I found the letter to be quite compelling, and Gwynedd and I arranged to talk one Sunday afternoon. The idea of using dance to communicate the importance of monarch conservation was intriguing, but I was skeptical. I didn’t have a clear vision of how this might work and, as with any creative process, Gwynedd needed time for her initial idea to develop and emerge. We spoke many times over the next few months, mostly when I was working in the lab on Sunday afternoons. These were good times to talk since were no interruptions and I did a lot of listening as Gwynedd explored various ideas and tried to bring together a team that could help her fulfill her vision. Late in the spring, the team began to come together, and we started planning how to arrange for Gwynedd and her production crew to come to Kansas to film her first monarch conservation video. I made arrangements with my neighbors Dan and Linda Haney to do some filming on their property and through Dr. John Briggs to conduct most of the shoot on the Konza Prairie just outside of Manhattan, Kansas.

monarch-population-figure-monarchwatchGwynedd testing her wings on the Konza Prairie (23 June 2013). Photo by Chip Taylor.

Gwynedd and her Moving for Monarchs crew arrived in Lawrence for a photo shoot and interviews at Monarch Watch on the afternoon of the 21st of June. Late in the day, we drove to the Konza Prairie to view the shooting locations planned for the next two days. Flowering in the prairie was at its peak with literally thousands of butterfly weeds (Asclepias tuberosa) and other milkweeds in full bloom. The weather during the shoot was iffy with strong winds. Splashes of sunlight scattered over the landscape though gaps in rapidly moving multicolored clouds – some of which shed a tear or two on the prairie. We worked around the rains and the winds and completed the filming late on Sunday the 23rd of June. What followed the trip to Kansas is best told by Gwynedd. The process of post production was long and complex. Gwynedd and Gabriella (the Director of Photography) live in NYC and Washington D.C., respectively, so the process involved a number of bus and train rides as well as extensive online file sharing–tasks completed on a volunteer basis by the young artists. Throughout these stages, Gwynedd and team carried on – working on the project whenever they could while also developing the promotion for the Kickstarter project. I can’t wait for you all to see the film–it speaks to awakening the need to conserve the monarch migration.

Below is the letter that made me Move For Monarchs.

Date: Wed, 20 Mar 2013 22:34:04 -0400
Subject: Hoping to speak with you
From: Gwynedd Vetter-Drusch

Dear Professor Taylor,

I am writing to you after having read the article “Monarch Migration Plunges to Lowest Level in Decades” from the New York Times last week. I would like to take positive action to raise awareness and implement solutions, such as those you have proposed in your latest blog post (including the planting of large amounts of milkweed) in order to counteract the effects of loss of monarch habitat.

I am a 21 year-old dancer, actor, and writer living, studying, and working in New York City. However, I have not always lived in New York. I grew up, in fact, in the small town of Manson, Iowa. My family moved to Manson from Seattle, WA, when I was about nine years old. It was in Manson that I discovered monarchs.

As a child I roamed our family farm (my family has been farming in the area for four generations), including a seven acre pasture which has never been tilled. They say you can still see the stagecoach tracks where the stagecoach used to run through those seven acres. This pasture sat on the edge of town, just across from Rose Hill Cemetery.

During the hours I spent outside in the summertime, I noticed that dozens of monarchs would fly back and forth across the road from the pasture to the cemetery and back again. One day I followed them from the pasture, which was full of milkweed, to the cemetery.

There I saw one of the most beautiful things I have ever seen. As I walked down a row of the largest old trees in the cemetery, I realized that the leaves on the branches were shifting and moving. When I came closer, I discovered that the leaves were actually butterflies, turning the branches a rusty orange. It was a large group of butterflies, I would say over a hundred monarchs at least (though to me the numbers seemed even greater), and they had situated themselves on the branches.

If you walked among them or moved a low-hanging branch, the world around you would explode in fluttering orange.

I cannot fully describe the effect that this and other experiences with monarchs have had on me. But those encounters have shaped my work as a performing artist, have been the subject of my poetry and a children’s book I am working on, and have had a profound impact on who I am as a person.

Throughout middle school and high school, I attended various science and environmental leadership camps through the University of Iowa and Northland College (in Ashland, WI). Biology was one of my favorite subjects, and Rachel Carson became one of my personal heroes. However, over time and through some surprising events, my focus shifted to the study of classical ballet, and that took me from Iowa to New York City at the age of 17.

Yet, I have always carried the memory of monarchs with me. Their delicate strength—their ability to migrate so far on seemingly paper-thin wings—has often been the source of personal inspiration when I encountered difficulties throughout my dance studies. In fact, the parallels between monarchs and ballet dancers are striking. Not least among these is the physical transformation of butterfly from earth-bound caterpillar to flying creature, which is like the transformation of dance student to full-fledged dancer, capable of performing amazing physical feats—including hanging for a moment in suspension in the air:  flight.

Perhaps this seems to romanticize a living organism, but in a way monarchs have a sort of mythological appeal. They are these incredibly beautiful, vulnerable creatures who go on a migration journey. I believe that this is one level that every person can relate to, and it is on this level that even those who do not understand the inherent worth of a species in its rightful function within a living system can begin to understand. And they can be inspired to take action.

I feel strongly compelled to take action myself, and as I lay awake in bed for several hours the night after reading the article, an idea came to mind, and I could not sleep until I had gotten out of bed and written down the details. I have been continuing to develop it since then.

I see a way to raise awareness of the problems facing monarchs and help Monarch Watch and other groups in their efforts to solve the problems. What I see combines the art forms of dance and photography (and perhaps film) and the power of the internet in a way that makes the issue highly visible.

I would be very interested in starting a conversation with you about this idea, either by phone or by email, whichever you prefer.

I can be reached at the following number, or at this email address.

Sincerely,
Gwynedd Vetter-Drusch

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The Northward Migration: when does it end?

24 June 2013 | Author: Chip Taylor

There are numerous unanswered questions about monarchs. What causes the migration to start in the fall? Why do they fly to Mexico? Why do the overwintering colonies form where they do? Why do the monarchs halt their southern flight at 19.5N? Why not go further? These, and other unanswerable questions, are asked of us frequently. We have to admit that we don’t know the answers but offer speculation and a best guess when we can. Curiously, though many of those we talk to know that monarchs do not continue to migrate through the heart of the breeding season, no one asks – when does the northward migration end in the spring and early summer? Well, it’s a good thing no one asks that question — because we don’t know the answer to that one either.

So when does the northward push by first generation monarchs* end? If there is a celestial component to when monarchs stop moving such as day length or the rate of change in day length or some other factor, is it possible for monarchs to arrive too early in the northern latitudes such that they fly beyond the limits of milkweed? Or, the converse, do conditions during some springs limit northward flight such that the monarchs do not reach the northern limits of milkweeds? In other words, is it possible during extremely cold springs that the “stop signal” whatever it is, is perceived before all the breeding habitat is effectively colonized? I think both things happen but I can’t argue effectively for these possibilities because there is virtually no data on this subject and relatively few credible observations. Years ago I directed one of the undergraduate students I was working with to make daily observations of directional flight by monarchs moving through this part of eastern Kansas in late May and early June. To our surprise, all directional flight appeared to end around the 5-7th of June. Monarchs present in the area were decidedly non-directional after the 7th. Day length is 14h 49m here on the 7th but the amount of change per day is declining rapidly (47 seconds from 7th to 8th) as we approach the summer solstice on the 21st. On that day the daylight period is 14hrs and 54 minutes.

This observation raises some questions. Do monarchs stop moving when the rate of change in day length drops substantially below a minute per day, and does this mean that monarchs stop directional movement progressively with increasing latitude?

The day-to-day differences become progressively smaller as one approaches the equinox. For example, at Duluth, MN, day-length increases by 25 seconds on the 14th and by only 11 seconds on the 18th.

Let’s see what happens at different locations as we move northward:

Daylength in June
Location
7th
21st
Change/day
Lawrence, KS
14h 49m
14h 54m
7th-8th 47 seconds
Des Moines, IA
15h 06m
15h 12m
7th-8th 48 seconds
St. Paul, MN
15h 30m
15h 37m
9th-10th 48 seconds
Duluth, MN
15h 45m
15h 52m
9th-10th 49 seconds

Note that the rate of change (less than 50 seconds per day) shifts from the 7th to 8th for Lawrence to the 9th-10th for St. Paul. Thus, if migration northward ends as a function of latitude and rate of change per day, we would expect the most northerly monarchs to still be showing directional flight even though directional flight has stopped further south.

This is certainly an interesting possibility but we need data and, as I said, there is virtually none. So here is where those of you making observations of first sightings can help. If you see a monarch, note its flight behavior. Is it nectaring, searching for oviposition sites or is it showing directional flight? And, if it is showing directional flight, what direction is it moving – that is, what is its compass bearing (approximate bearings would do for a start**)? Directional flight is particularly difficult to observe in the spring. In most cases the butterflies are flying quite fast at a height of 3-4 meters. If you are driving on east -west roads during May and June look for monarchs crossing in front of you from S to N (or NE) at a height just above your car or pickup.

Observations of directional flight are valuable and will further our understanding of monarch behavior. Such observations could be shared with our email discussion list (Dplex-L) or reported to Journey North. Systematic studies by students or even groups of citizens of directional flight over a series of weeks in the spring and early summer at different latitudes could resolve this question. An alternative approach would be experimental releases with monarchs that had been reared under specific natural conditions or by using a flight simulator.

*First generation monarchs are offspring of monarchs that overwintered in Mexico. The first of these monarchs begin moving north in the last week April, with most moving north in May and early June.

** Many smart phones have a compass app available to them. To obtain the bearing of a monarch moving directly away from you, point the phone at the monarch and take a screen shot of the compass. The image should be time-stamped and may even include latitude and longitude so it can be reviewed later.

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