Anurag Agruwal: Great News for Monarch Overwintering Population

The estimates of the monarch butterfly overwintering population were announced today (Wed. Jan. 30th 2019) by WWF Mexico.  The butterflies are so dense at their dozen or so mountain-top clustering sites that overwintering butterflies cannot be counted individually.  Instead, the area of forest that is densely coated with butterflies (at about 5,000 butterflies per square meter looking up into the canopy) is estimated as a measure of monarch abundance.  Butterflies arrive to Mexico around the day of dead in November and stay until March each year as part of their annual migratory cycle.  Butterflies have been declining over the past three decades, and the annual announcement is a welcome addition to our understanding of the long-term dynamics of our beloved monarch.

The annual multi-generational migratory cycle of the monarch butterfly. The southernmost red dot indicates the high elevation overwintering grounds in central Mexico where populations are censused. North pointing arrows indicate the spring and summer generations that migrate, breed, and eat milkweed. Learn more in my book Monarchs and Milkweed.

This winter season (2018-2019), there were approximately 6.05 hectares (nearly 15 acres) of forest occupied with dense monarchs in the Mexican highlands (somewhere in the neighborhood of 300,000 million overwintering butterflies).  The monarchs end up congregating in a tiny area, with the bulk of the butterflies concentrated among twelve mountain massifs (clusters of peaks) within three hundred square miles (eight hundred square kilometers), an area smaller than New York City. In other words, most of the monarchs from eastern North America, from Maine to Saskatchewan, and south to Texas, probably covering two million square miles, funnel down and overwinter in a location 0.015 percent the area that they occupy in the summer!  Unbelievable. This year’s estimate is well over double compared to last year, great news for monarchs!

Where does this leave us?  The good news is that this year’s population was huge in the summer months throughout the USA and Canada, and the resulting migration and overwintering population in Mexico was the highest in 12 years, higher than predicted by many.  The season started with a very early spring and a far reaching northern migration.  As I have previously argued, there is often a disconnect between summer breeding populations of monarchs and the overwintering population — that seems to not be the case this past year.

With 26 years of data, there are various ways to plot and assess the trends.  Below I have plotted four year averages for seven periods working backwards (so the first average on the left is only for 2 years).  Any way you slice it, the trend has been negative, and the population is not what it was.  Nonetheless, the extreme downward trend seems to have bumped up in the last period of four years.  Is this the new norm, a winter population hovering between two and five hectares?  How dangerously low are these numbers? And what can be done to continue to reverse the trend and buffer the population?  I have recently written more about this issue in a scientific article as a well as my book.

For now, let’s celebrate. The government is open, and thus the Fish and Wildlife Service will be deciding on the petition to list monarchs as threatened under the Endangered Species Act this summer. Looking forward to seeing butterflies and their caterpillars once Ithaca, NY thaws in spring. Thanks for reading! 

Anurag Agrawal is a professor in the Department of Ecology and Evolutionary Biology and the Department of Entomology at Cornell University. He is the author of Monarchs and Milkweed and lives in Ithaca, New York.

 

 

Seyla Benhabib: Exile, Statelessness, and Migration. Playing Chess with History from Hannah Arendt to Isaiah Berlin

Exile, Statelessness, and Migration explores the intertwined lives, careers, and writings of a group of prominent Jewish intellectuals during the mid-twentieth century—in particular, Theodor Adorno, Hannah Arendt, Walter Benjamin, Isaiah Berlin, Albert Hirschman, and Judith Shklar, as well as Hans Kelsen, Emmanuel Levinas, Gershom Scholem, and Leo Strauss. Informed by their Jewish identity and experiences of being outsiders, these thinkers produced one of the most brilliant and effervescent intellectual movements of modernity.

The title of your book “Exile, Statelessness, and Migration” suggests many different issues that could be the subject matter of sociology, law, cultural studies, migration studies etc. Yet the book is about the “intertwinement” of the lives and ideas of some of the most significant Jewish intellectuals of the previous century: Hannah Arendt, Walter Benjamin, Theodor Adorno, Emmanuel Levinas, and a generation of thinkers younger than them such as Judith Shklar, Albert Hirschman and Isaiah Berlin.

I am fascinated by how these thinkers experienced exile, migration, and statelessness in their own lives and how this is reflected or refracted in their writings. While these themes are central to Hannah Arendt’s, and in later years, to Judith Shklar’s work, Albert Hirschman did not write about the loss of citizenship but rather about “exit, voice, and loyalty.” Yet as I show in my chapter on him, “exit” can also refer to having to exit or leave a country, a homeland, and not just to leaving a firm, as is often supposed that Hirschman refers to. This dimension of political exit becomes clearer in Hirschman’s work as he revisits his birth city of Berlin many years after leaving it as a young socialist militant.

Isaiah Berlin’s case is very interesting in that rather than being an exile or a stateless person, he is a paradigm of successful integration into the host culture. Yet in his case as well, multiple loyalties and their conflicts continue, such as to the Russian culture of his childhood, to Israel and the Jewish people and to his Majesty’s UK. How do these loyalties influence his understanding of pluralism and his claim that there can be no universe that encompasses all human values worth cherishing and that one must choose one or the other among them? These are fascinating questions.

But why is your subtitle “Playing Chess with History” ?

Hannah Arendt and Walter Benjamin were political refugees in Paris from 1933 to 1940 and they taught Arendt’s future husband, Heinrich Bluecher, to play chess. I open the book with the correspondence among the three of them concerning these chess games.

Bluecher belonged to the Spartacist League of the German communist movement, which he abandoned after the murder of Rosa Luxemburg and Karl Liebknecht in January 1919. As is well-known, one of Walter Benjamin’s most famous writings, “Theses on the Philosophy of History,” opens with the unforgettable description of an automaton in old Turkish attire playing chess. The movements of the puppet chess master are controlled by a dwarf sitting invisibly under the chess table. We know from historical sources that such automatons existed and were much cherished in the European courts of the Enlightenment.  We also know from Benjamin’s own writings that for him the image of the old Turk playing chess, but whose moves are controlled by an invisible dwarf, was a metaphor for those who believed, such as orthodox Marxists did, in the inexorable march of history. Individuals may have thought they controlled their own destinies but really only the dialectical laws of history did. Benjamin bought none of that and he thought that politically such a conception of history led to quietism and capitulation Rather, argued Benjamin, history does not consist of the inevitable march of uncontrollable forces but it is a contingent assemblage of events in the midst of which a Messianic, wholly unexpected, moment of redemption can emerge.

I argue that Arendt, as well as Adorno, were indebted to Benjamin’s idea of “constellations’’ and the eruption of the “new” and the unexpected in history. The tangled personal and intellectual relationship between Arendt, Benjamin, and Adorno is one of the central questions in the book.

The metaphor of playing chess with history is also applicable to Shklar’s escape with her family from Riga, Latvia over Sweden, then Siberia, to Japan, and eventually to Montréal, after a brief stint in New York.

We also learn from Jeremy Adelman’s fantastic biography of Albert Hirschman, The Worldly Philosopher. The Odyssey of Albert Hirschman (2013), that in the 1940’s, Hirschman was helping the American Friends Committee settle refugees in the US by forging papers for them in Marseille, France such as to enable them to cross the border from occupied France to Spain. Among those who were helped to escape via this route were Hannah Arendt and Heinrich Bluecher but, alas not Walter Benjamin, who would commit suicide in the Spanish border town of Port Bou. Hirschman certainly was among the few militants and resistance fighters of the time who helped refugees like Hannah Arendt to leave Europe. The pieces of the chess game were in place but not known to the players themselves.

Jewish identity and otherness runs through these chapters like a red thread; the others being, exile, voice and loyalty; legality and legitimacy, and pluralism and the problem of judgment. Can you say more about them?

I want to clarify that my goal in this book is to practice a form of thick historical contextualization that aims at elucidating central dilemmas of modern states and societies which have a lasting significance for us as well. That is how I understand the term “force fields” which I borrow from Martin Jay. In a “force field,” a cluster of ideas and themes develops as a result of the strength of the center pulling these elements toward itself, while there are also centripetal forces pushing them away from the center as well as one another.

The thinkers considered in this volume, Arendt, Adorno, Shklar, Hirschman, and Berlin, along with many others such Scholem, Benjamin, Leo Strauss, and Hans Kelsen with whom they were in dialogue, were challenged by Max Weber’s diagnosis of modernity as a process of “rationalization.” According to Weber, modernity brought the application of a form of scientific and technocratic world-view to culture and society, which he famously also described as one of “Entzauberung,” that is, the loss of magic in our understanding of nature and culture. Entzauberung also results in a pluralization and fragmentation of values such that it is only individual act choice and commitment that can now give meaning and significance to what is otherwise meaningless and inert. How can such a society and culture stabilize themselves, create political legitimacy as well as the spiritual resources for modern individuals to go on to “face the times like a man,” (sic) as Weber puts it?

Shklar was intimately familiar with Weber’s work and named her second book, Legalism, thereby evoking the well-known distinction between legality and legitimacy. Shklar’s concept of legalism, like Weber’s typology of legal-rational authority, means that the legal system is a formally correct and self-referential whole that generates correct statutes and rules in accordance with the proper application of procedures. Whether this machinery of legality produces justice, respects human rights or enhances citizens’ autonomy is a moot question. Legal-rational authority may presuppose a Grundnorm, a foundational norm, which once set into place, serves as the ultimate source of legitimacy, as Hans Kelsen argued. But what then justifies this Grundnorm? Weber himself thought that the machinery of legal-rational authority would fall prey either to “sensualists without heart and bureaucrats without spirit,” and/or be hijacked by charismatic and demagogic leaders. Modern systems of legitimacy remained unstable, and Weber did not have much faith that liberal democracies could endure without sliding into some form of authoritarianism.

Shklar understood Weber’s challenge and she turned to the moral psychology of the citizens of post-war liberal democracies and their practices of citizenship as well wage-earning; she saw such activities as providing new forms of dignity and forestalling cruelty. Departing sharply from system-building in the mode of German thought, Shklar sought to ask the important questions rather than provide tightly argued systematic answers.

Isaiah Berlin had so intensely internalized Weber’s challenge that, as I show in chapter 9, at times he acknowledged it while at other times denying Weber’s Influence of the fragmentation of values in modernity upon his own thinking. As opposed to Weber, Berlin’s thesis of the pluralism of values does not describe a condition unique to modernity but is characteristic of previous historical epochs as well. For Berlin, the human horizon contains multiplicity of values, not all of which can be realized either by individuals or by societies at any one point in time. Berlin is, of course, insistent that pluralism is not relativism and it does not mean that we must accept all values. Yet it is unclear how Berlin defends this distinction between pluralism and relativism without resorting to some conception of human nature, essence or condition. Berlin’s answers imply that although we cannot provide deductive, incontrovertible philosophical justifications for why some values are worth defending while others are not, nonetheless we can exercise correct judgment for which good reasons can be given.

I end the book with the “burdens of judgment” as Rawls calls them. Already Arendt as well as Adorno had turned to Kant’s distinction between “determinative” and “reflective” judgment to articulate a new relationship between the universal and the particular. Like Rawls, they had already argued that the work of judgment did not consist in the subsuming of the particular under the universal alone, but in the interpretative work of finding the proper universal -principle, model, or paradigm- if such existed at all. Arendt, in particular, followed Kant’s teaching of the enlarged mentality and the ability to think from the standpoint of others. For her, whatever else good judgment involved, it had to entail these qualities as well.

What about exile, voice and loyalty? You have not said much about that yet.

One of the best known answers to Weber’s question concerning legitimate authority was given by Carl Schmitt, who argued that the realm of the political was constituted by the distinction between ‘friend’ and ‘foe.’ For Schmitt, legality did not rest on a Grundnorm but on the existential decision of a political entity to constitute itself as one distinguished from others whom it considered “foes.” There is a long scholarly discussion about Schmitt’s Nazism and whether his concept of foe simply means an adversary with whom I can have interest conflicts or whether the foe is an existential other. I think that Schmitt cleverly left this ambiguous but that over time his thought evolved in the direction of naming liberalism, cosmopolitanism, world-Jewry and Anglo-American democracy as the existential enemies of his political vision.

Schmitt’s challenge is not easily dispensed with because every polity – including liberal democracies – distinguishes between a ‘we’ who are considered full citizens entitled to voice and of whom loyalty is demanded, in Hirschman’s terms, and ‘others’ who do not belong to the demos. Arendt faced the problem of statelessness in her own life when Germany denaturalized its Jewish citizens and she articulated the paradoxes of the right to have rights for those who had been rendered rightless by totalitarian practices.

As a political economist Hirschman’s concerns are different. He analyzes which schemes of development can enable local economies to utilize all their resources such as to jump start the move out of poverty and dependency. Yet, like Arendt, Hirschman is also concerned with the paradoxes and weaknesses of the nation-state and early on comes under the influence of the Italian socialist federalist movement, among whose members are Eugenio Colorni and Alberto Spinelli. They compose, while in prison, the Ventetone Manifest which envisages a radical restructuring of the institutions of post-war Europe along federalist lines and the taming of the power of nation-states.

This federalist vision resonates with Arendt’s proposals of the late 1940’s for a Mediterranean federation of peoples as a possible way out of the Israeli-Palestinian quagmire. Some scheme of federalism or federationalism constituted Arendt’s as well Hirschman’s answer to the choices of exit, voice and loyalty.

I end the book with the observation that a time when the crises of our republics are reaching Weimer-like proportions, recalling the lives and works of these emigré intellectuals gives one both fear and hope: fear, because the one country that opened its arms to so many of them, namely the United States, is reproducing the Weimar syndrome of xenophobia and lawlessness in its treatment of migrants and refugees; hope, because their reflections show that catastrophes can be overcome and new beginnings are possible in political life.

Seyla Benhabib is the Eugene Meyer Professor of Political Science and Philosophy at Yale University. Her many books have been translated into more than fourteen languages, and include Dignity in Adversity, The Rights of Others, and The Claims of Culture (Princeton).

Anurag Agrawal: Monarch butterflies—out of sight, but not out of mind!

By Anurag Agrawal

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The annual migratory calendar for monarch butterflies in eastern North America.

As winter approaches, monarch butterflies are not in sight for most Americans. Beginning in the fall, hundreds of millions of butterflies east of the Rocky Mountains oriented south and began their migration. And indeed the story of how they navigate is truly remarkable: the little insect uses a sun compass that is adjustable depending on the time of day to find its way. Details of the migration and much more are in Monarchs and Milkweed: A Migrating Butterfly, a Poisonous Plant, and their Remarkable Story of Coevolution. And 2017 was a spectacular fall season for monarch butterflies. As far as most monarch biologists can remember, this was perhaps the biggest summer season on record, with monarchs in epic numbers congregating and flying south.

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Southward migrating monarchs in Ontario during autumn. Although monarchs are usually dispersed in the summer, as the fall migration takes hold, butterflies congregate in larger clusters.

As the holiday season approaches, it is useful to keep in to keep in mind where monarchs are and what they are doing.  Cool and concentrated, they huddle en masse for nearly five months.  Will the numbers of butterflies overwintering in Mexico this year show a rebound from their precipitous decline?  If the migration was successful, yes, we all expect (hope!) the numbers to be up.  But only time will tell, as the official numbers are typically announced each February by World Wildlife Fund Mexico.  The monitoring of these unimaginable aggregations of butterflies has been a critical piece in the conservation puzzle for monarchs.

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The state license plate in Michoacán State, Mexico.

In November around the Day of the Dead and leading to American Thanksgiving, monarchs arrive to their overwintering grounds in the highlands Michoacán, Mexico. And legend has it that the butterflies are the returning souls of loved ones. They form clusters that are so dense, they weigh down the Oyamel Fir trees they inhabit above 10,000 feet of elevation in these exquisite sites. The sites are terribly small, with all of them fitting into area smaller than New York City.

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A congregation of monarchs within the Monarch Butterfly Biosphere Reserve, a UNESCO World Heritage Site. Most wings are closed, but look for the orange spots of open butterfly wings.

But before 1975, there was no conservation conversation about monarchs, because scientists simply did not know where monarchs went in the winter (of course native Mexicans of the region have known for centuries).  More importantly, we didn’t know how restricted and sensitive their overwintering sites are. The story of how the monarchs were found is too lengthy to recount here, but it is an astonishing story. In short, Professor Urquhart from the University of Toronto was hot on the trail, and knew that they flew south into Mexico during the fall.  Nora and Fred Urquhart marshaled a citizen science campaign that included a massive effort to engage folks far and wide in the search for the overwintering grounds.  In fact, in 1973, they wrote an article in an English language newspaper in Mexico City requesting help in finding the monarch overwintering sites.

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I obtained this reproduction of the original article outlining monarch butterfly biology and requesting help finding the overwintering grounds from the Library of Congress. It came on microfiche and was a treasure to hold and read.

Still, it was another two years before the overwintering colonies were found and reported to the world. After thirty years of tagging butterflies, enlisting thousands of citizen scientists, and much speculation, shortly after new year’s day in January 1975, the great discovery was made. The Urquharts wrote to their thousands of volunteers: “We now wish to announce to our associates, that, after these many years of intensive study, after having tagged thousands of migrants, we have, finally located the exact area where they overwinter, with the very able assistance of Ken Brugger and Cathy Brugger of Mexico City”. And the rest is history.

Anurag Agrawal is a professor in the Department of Ecology and Evolutionary Biology and the Department of Entomology at Cornell University. He lives in Ithaca, New York.

Agrawal

Just in Time for Migration Season: The Warbler Guide

The Warbler GuideWarblers are among the most challenging birds to identify. But, as we enter the fall migration season, Princeton University Press has the perfect tool for identifying these beautiful birds: The Warbler Guide.

This helpful guide enables readers to quickly identify any of the 56 species of warblers in the United States and Canada, with more than 1,000 stunning color photos, extensive species accounts with multiple viewing angles, and an entirely new system of vocalization analysis that helps you distinguish songs and calls.

This is the perfect tool for birdwatching, making warbler identification easier than ever before. But fear not: we are pleased to offer some of these tools to print, laminate, and take with you as you set out on your own adventures. Below, we have eight different finder keys – you can also download them in a complete set as a PDF or JPG. Additionally, we have a tip sheet on identifying the age and sex of warblers, including those from the West Coast. Take these with you on your next birdwatching trip, and then check out the complete Warbler Guide for additional information and insights.

 

Face Quick Finder

Face Quick Finder PDF | JPG

45 Degree Quick Finder

45 Degree Quick Finder    PDF | JPG

East Fall Quick Finder

East Fall Quick Finder        PDF | JPG

East Spring Quick Finder

East Spring Quick Finder    PDF | JPG

Side Quick Finder

Side Quick Finder PDF | JPG

Undertails Quick Finder

Undertails Quick Finder     PDF | JPG

Underview Quick Finder

Underview Quick Finder     PDF | JPG

West Quick Finder

West Quick Finder PDF | JPG

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Bird Fact Friday – Weekly Warbler: Black-throated Blue

From page 192-193 in The Warbler Guide:

Black-throated Blue Warbler, Fall Female, credit Scott Whittle

The female Black-throated Blue Warbler’s blue-green back and buffy undersides create a relatively low-contrast appearance. Its darker cheek creates a faint mask. Though from some angle, the mask can be very prominent. A small white “handkerchief” mark is created by white coloration at the base of the outer primaries. The Black-throated Blue Warbler is an active, understory forager, often seen near eye level. It frequently makes a loud, dry, “kissy” chip call while foraging in the fall. The Black-throated Blue Warbler is a good example of sexual dimorphism: the male and female are very different in color, although their body structure is the same.

 

 

The Warbler Guide
Tom Stephenson & Scott Whittle
Drawings by Catherine Hamilton
Warbler Guide App
Species Account Example: American Redstart Male

Warblers are amwarblerong the most challenging birds to identify. They exhibit an array of seasonal plumages and have distinctive yet oft-confused calls and songs. The Warbler Guide enables you to quickly identify any of the 56 species of warblers in the United States and Canada. This groundbreaking guide features more than 1,000 stunning color photos, extensive species accounts with multiple viewing angles, and an entirely new system of vocalization analysis that helps you distinguish songs and calls.

The Warbler Guide revolutionizes birdwatching, making warbler identification easier than ever before. For more information, please see the author videos on the Princeton University Press website.

Bird Fact Friday – Weekly Warbler: Blackpoll

From page 182-183 in The Warbler Guide:

The Blackpoll Warblers (fall birds) have yellowish throat and breast in contrast with the white lower belly. They have bold white wing bars, and distinct eyeline with broken eyering. The Blackpoll Warblers have contrasting tertial edging, and flight feathers white-edged on tips. Their streaking in sides and back is always present even when faint. Their long wings indicate a long-distance migrant: up to 7,000 miles each way—more than any other warbler.

The Warbler Guide
Tom Stephenson & Scott Whittle
Drawings by Catherine Hamilton
Warbler Guide App
Species Account Example: American Redstart Male

Warblers are amwarblerong the most challenging birds to identify. They exhibit an array of seasonal plumages and have distinctive yet oft-confused calls and songs. The Warbler Guide enables you to quickly identify any of the 56 species of warblers in the United States and Canada. This groundbreaking guide features more than 1,000 stunning color photos, extensive species accounts with multiple viewing angles, and an entirely new system of vocalization analysis that helps you distinguish songs and calls.

The Warbler Guide revolutionizes birdwatching, making warbler identification easier than ever before. For more information, please see the author videos on the Princeton University Press website.

Anurag Agrawal: The oldest butterflies?

by Anurag Agrawal

It’s unclear when humans became humans. Presumably it was a gradual growth of our consciousness over the eons. There are some things, however, that appear to distinguish us from most other animals. For example, our artistic depictions. From the deepest, darkest caves have emerged pictures of humanity from thousands of years ago. And in an Egyptian tomb, that of Nebamun, on a painting called “Fowling in the marshes” (from around 1350 BCE) comes one of the oldest human depictions of butterflies. It happens to be of the African Monarch, Danaus chrysippus, sometimes called the plain tiger, a close relative of our beloved North American Monarch butterfly, Danaus plexippus.

Agrawal
I stumbled on this lovely scrap of history when a friend and colleague, Harry Greene, gifted me a book: Nabokov’s Butterflies (2000), a collection of unpublished and uncollected writings. Some explanation is in order. Harry is an extraordinary naturalist and big thinker in ecology and evolution. Like many senior scholars, his predicament was the lack of shelf-space in his office. And so I was the beneficiary of Nabokov’s Butterflies. Vladimir Nabokov, a Russian-American author, and noted entomologist, was most famous for his writings, for example, Lolita, and his celebrated translation of Pushkin’s novel in verse, Eugene Onegin. His ideas about biology were diverse, he was a passionate lepidopterist, and he often intermixed his literary writing and entomological excursions. Lolita is said to have been written primarily on butterfly collecting trips in the American west. Nonetheless, Nabokov also clung on to other ideas that held little merit in the scientific sphere. Most prominently, Nabokov rejected evolution by natural selection as a driver of certain organismal traits that he deemed ‘coincidental, miraculous, or too luxurious.’

Agrawal

Nabokov was a professor at my own Cornell University in the decade following WWII. Although he taught literature and had well-known students at Cornell (including U.S. supreme court justice, Ruth Bader Ginsburg), his entomological interests continued. In fact, after he retired from Cornell in the mid-1960s, Nabokov had sketched out an outline of a book: The Butterflies of Europe. And although the book never came to be, the outline was recapitulated in Nabokov’s Butterflies. Flipping through the book, I stumbled on his entry for Danaus in which he wrote, “This butterfly has the distinction of being the oldest known to have been represented by man. Seven specimens of it (with typical white-dotted Danaus body but somewhat Vanessa cardui like wingtips) are shown flitting over the papyrus swamp…” (page 603).

Agrawal
I later asked another friend, Harvard’s Lepidopterist, Naomi Pierce: did Nabokov have it right? On the money, she independently pointed to the similarity of Danaus chrysippus and the painted lady, Vanessa cardui, wondering if the butterflies on this three thousand year old tomb painting were Danaus or Vanessa. She concluded, as did Nabokov, that the African Monarch ruled. Detailed assessment of the color patterns on the wings were informative to both entomologists. The oldest human depiction of a butterfly? Perhaps not. Naomi mentioned some evidence of butterflies in Minoan artifacts from Crete, a thousand years earlier than Nebamun, and likely in Pyrenees cave paintings, some 10-30 thousand years earlier!

Of course, there is nothing special about being the oldest depiction of a butterfly by Homo sapiens. But suffice it to say, butterflies, metamorphosis, wing patterning, and the beauty of nature have been on our minds for a very long time. Thanks Harry and Naomi! And thanks Nabokov. Who knows what becomes of those side hobbies and obsessions we all hold.

Nabokov

AgrawalAnurag Agrawal is a professor in the Department of Ecology and Evolutionary Biology and the Department of Entomology at Cornell University. He is the author of Monarchs and Milkweed: A Migrating Butterfly, a Poisonous Plant, and Their Remarkable Story of Coevolution.

Bird Fact Friday – Weekly Warbler: Blackburnian

Blackburnian Warbler, Spring Male, credit Scott Whittle

From page 166-167 in The Warbler Guide:

The Blackburnian Warbler has fiery orange throat, face, and under-eye arc. Its auricular patch has distinctive triangular shape, pointed at rear and bottom. The Blackburnian Warbler has broad white wing patch, and two pale braces on back unique among warblers. Especially in a dim forest, the bright flash of a Blackburnian can be startling as they sally for insects. Blackburnians nest and are often found high in trees, but color often makes them quickly identifiable. Adult females in spring are not as bright orange as males. The Blackburnian Warbler is a long-distant migrant, and it has relatively long wings.

The Warbler Guide
Tom Stephenson & Scott Whittle
Drawings by Catherine Hamilton
Warbler Guide App
Species Account Example: American Redstart Male

Warblers are amwarblerong the most challenging birds to identify. They exhibit an array of seasonal plumages and have distinctive yet oft-confused calls and songs. The Warbler Guide enables you to quickly identify any of the 56 species of warblers in the United States and Canada. This groundbreaking guide features more than 1,000 stunning color photos, extensive species accounts with multiple viewing angles, and an entirely new system of vocalization analysis that helps you distinguish songs and calls.

The Warbler Guide revolutionizes birdwatching, making warbler identification easier than ever before. For more information, please see the author videos on the Princeton University Press website.

Anurag Agrawal: The migration patterns of the monarch butterfly

by Anurag Agrawal

The plight of monarch butterflies if often in the news: many scientists around the world are working hard to understand their annual migratory cycle. How do the monarchs produced during summer in the northern reaches of America contribute to the overwintering population in Mexico? The origin of monarch butterflies that make it to Mexico has been hotly debated because it has profound consequences for how we approach monarch conservation.

A new study is remarkable in its use of historical collections over the past 40 years and modern isotopic analysis. The scientists address the most important regions in the U.S. for producing monarch butterflies that actually make it to Mexico. This sort of data has been very difficult to come by and there has been a lot of speculation. As outlined in my new book from Princeton, the midwest has dominated discussions as being the most important region in the U.S. for monarchs. In the study, the authors find that the Midwest contributes a whopping 38% of the butterflies that make it to Mexico.

Monarchs

The regions studied by Flockhart et al. separated to highlight their relative areas

I would add two points for discussion. The first is that the areas of land that the authors designated as Midwest, Northeast, etc., seemed totally reasonable, but also somewhat arbitrary. In particular, an issue arises when you consider that, as designated in the paper, the Midwest is about 2.5 times as big as the Northeast. It is therefore not surprising that the Midwest produces about 2.5 times as many butterflies that make it to Mexico (38% vs 15%). In other words, the butterflies that make it to Mexico have about an equal probability of coming from the Midwest and the Northeast when land area is considered. Yet another way to think about this is that two states that are about equal sizes in the two regions (for example, Indiana and Maine) will on average produce about the same number of butterflies that make it to Mexico.

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The annual migratory cycle of the monarch butterfly from Monarchs and Milkweed. In my past research, we have opted for a three simple regions defined by the butterfly generations.

Quite interestingly, the North Central area (including my home in the Finger Lakes region of NY) is slightly more important for butterfly production given its size. When you factor out the area of the Great Lakes (where there are no monarch caterpillars), the area of North Central is small (36% of the size of the Midwest). Thus, about 20% more butterflies per square mile come out of the North Central than the Midwest or Northeast. Where does this leave us?  The agricultural Midwest is certainly important, but perhaps not as important as previously thought.

The other point worth thinking about is that the Southwest (read: Texas) comes out as big in terms of area (equal to the Midwest) and relatively less important in terms of contributing butterflies (11% of the total).  The critical importance of the Gulf States including Texas, however, is not in the last generation of butterflies produced in fall that migrate south, but rather in the first generation of butterflies that are produced in spring and that migrate north to the Midwest and Northeast.  In other words, the Gulf States are absolutely critical for the annual migratory cycle, even if that is not where fall migrants are produced.  Without a spring generation there, the Midwest and Northeast would be empty!  In chapter 9 of the book, I summarize the critical importance of Gulf States not only for the spring, but also in providing floral resources for fall migrating butterflies.

I hope we see more studies like this in the future, as it provides new important information and was inspiring to read.

AgrawalAnurag Agrawal is a professor in the Department of Ecology and Evolutionary Biology and the Department of Entomology at Cornell University. He is the author of Monarchs and Milkweed: A Migrating Butterfly, a Poisonous Plant, and Their Remarkable Story of Coevolution.

Bird Fact Friday – Weekly Warbler: Magnolia

Welcome back to the warblers!

Magnolia Warbler, Spring Male, credit Scott Whittle

As the warbler migration season approaches, we’re again highlighting some fun facts about the warblers with our Weekly Warbler feature. Kicking it off today is the Magnolia Warbler.

From page 340-341 in The Warbler Guide:

The Magnolia Warbler has bright yellow underparts and throat. Its tail pattern is unique and diagnostic—it has a black tail with broad white base. It often spreads tail, showing white tail spots very high in tail. The Magnolia Warbler has a black face mask with white eyebrow stripe and white under-eye arc. It is one of the three warblers that have a bright yellow rump (along with Yellow-rumped and Cape May). The Magnolia Warbler has a heavy black necklace that extends down sides. It is moderately active, usually in low to mid-story. During migration it is versatile, foraging in many habitats.

 

The Warbler Guide
Tom Stephenson & Scott Whittle
Drawings by Catherine Hamilton
Warbler Guide App
Species Account Example: American Redstart Male

Warblers are amwarblerong the most challenging birds to identify. They exhibit an array of seasonal plumages and have distinctive yet oft-confused calls and songs. The Warbler Guide enables you to quickly identify any of the 56 species of warblers in the United States and Canada. This groundbreaking guide features more than 1,000 stunning color photos, extensive species accounts with multiple viewing angles, and an entirely new system of vocalization analysis that helps you distinguish songs and calls.

The Warbler Guide revolutionizes birdwatching, making warbler identification easier than ever before. For more information, please see the author videos on the Princeton University Press website.

A new giveaway to get you ready for spring warbler migration

With the spring migration underway, take the opportunity to head to the field and watch these brightly colored neotropical migrants travel back north.

WarblerThe Warbler Guide is an essential resource for any warbler enthusiast, and the most comprehensive and user-friendly source for warbler information that makes warbler identification easier than ever.

Not feeling like carrying a book? PUP also offers many portable options. You can download the Warbler Guide App (now available for both Apple & Android devices) to get all the benefits of the book in the palm of your hand, plus many more app-only features. For example, with the rotatable 3D models that enable you to see a warbler from any angle, you can identify a warbler from the exact position you see it.

You can also download our FREE Quick Finders in pdf or jpg. Offering a quick snapshot of every North American species of warbler for side-by-side comparison, the Quick Finders sort warblers in a variety of ways to suit your needs.

WarblersIt’s also time for a new giveaway! Seven winners will receive a copy of the North American Warblers Fold-out Guide—a handy, pocket-sized foldout reference, with QR codes that take you to a range of common vocalizations for each species. Follow the directions below—the entry period ends April 20!

You can also check out Nicholas Lund’s tips and advices on birdwatching during spring migration, or check BirdCast for realtime bird forecasts that track the waves of migrants.

Armed with the most helpful tools and guides, you just might have your best spring birdwatching season ever!

 

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Anurag Agrawal on Monarchs and Milkweed

AgrawalMonarch butterflies are one of nature’s most recognizable creatures, known for their bright colors and epic annual migration from the United States and Canada to Mexico. Yet there is much more to the monarch than its distinctive presence and mythic journeying. In Monarchs and Milkweed, Anurag Agrawal presents a vivid investigation into how the monarch butterfly has evolved closely alongside the milkweed—a toxic plant named for the sticky white substance emitted when its leaves are damaged—and how this inextricable and intimate relationship has been like an arms race over the millennia, a battle of exploitation and defense between two fascinating species. Check the PUP blog each Monday for new installments in our “Monarch Monday” blog series by Anurag Agrawal.

What makes monarchs and milkweeds so special?

AA: Monarchs and milkweed are remarkable creatures, they’re on a wild ride! From the monarch’s perspective, its only food as a caterpillar is the milkweed plant. This makes them highly specialized, highly evolved, and very picky eaters indeed. They’re actually not that unique among butterflies, but they are extreme. Milkweed does everything in its power to defend itself against being eaten by monarchs. They make sandpapery leaves, toxins that can stop a human heart, and a thick poisonous goo that can glue an insect’s mouth shut. Again, although milkweed is not unique among plants, it is extreme. In what is called a coevolutionary arms race, monarchs and milkweed have been continually evolving over the eons to keep up with each other. As such, they have a lot to teach us about the way nature works, the way plants and animals interact, and about the various paths that evolution can take different species. And this is all to say nothing of the monarch’s spectacular annual migration, often over 3,000 miles flown by individual butterflies, using the sun to navigate, and having stored away milkweed’s poisons to protect themselves from being eaten by birds. Monarchs and milkweeds are royal representatives of all interacting species.

Why did you write this book?

AA: After studying monarchs and milkweed myself for over 15 years, I felt like I had a lot I wanted to share, especially with non-scientists and nature lovers. Monarchs and milkweed are such fascinating organisms, and yet so much of their beautiful biology is not widely known. I also wrote the book because there are areas of my own knowledge about monarchs and milkweed that I wanted to immerse myself in, but that I had not yet done any research on. So as an author, getting to visit the overwintering sites in Mexico, to study the population decline of monarch butterflies, and to understand their mating rituals were all fascinating detours from my everyday research life at Cornell University. The book was incredibly fun to write, and getting to work with artists and historians made it all the more rich. I hope that anybody that has an appreciation for nature, an interest in science, or just a curiosity about the ecology of plants and butterflies will enjoy this book. Working on this project has surely altered the course of my own research, the classes I teach, and how I see the natural world.

Why have you highlighted some of the personalities of the scientists studying monarchs and milkweeds in this book?

AA: One of the most amazing things about monarchs and milkweeds is the scientists who have studied them. They were such remarkable characters, especially those pioneering studies back in the 1950s: tremendously creative, sometimes competitive, and with some of their discoveries worthy of a Nobel prize. Getting to know them, both from their discoveries and their personalities, and how they interacted, has enriched my appreciation for how science is done. It also highlights the meandering and sometimes serendipitous nature of discoveries. I wanted to share the thrill of science, its ups and downs, and the process by which it is done with the curious reader.

Can you share one of your ah-ha! moments from studying monarchs and milkweeds?

AA: One of my favorites was from when I was an assistant professor at the University of Toronto. One day I was eating lunch by myself in a small downtown garden. Just by chance, I happened to sit on a bench beneath a very tall milkweed plant that had a very large monarch caterpillar feeding away. Without giving away all the details, that one hour encounter, in the middle of a city with 3 million people, changed my perspective on monarchs and milkweed forever. It was so unlikely an event, perhaps 1 in a 1,000 that a butterfly had been flying by and happened to lay an egg on this Toronto milkweed, and then a further 1 in 100 chance of that egg hatching and surviving to be that large caterpillar that I could watch it. And probably a 1 in a million event that I would happen to be eating lunch there, that day, to observe the events. In biology one has to work hard, be patient, and occasionally get very lucky! Throughout my studies on monarchs and milkweed, I have had tremendous luck in encountering wonderful biology that has had profound consequences.

Is the monarch butterfly going extinct?

AA: The answer to this very important and timely question is both simple and complex. On the simple side, there is no way the monarch butterfly is going extinct anytime soon. Having said that, the butterfly, and especially the long-distance migration that occurs every fall from Southern Canada and the USA, all the way to Mexico’s highlands in Michoacán, is indeed declining at a rapid pace, and we should all be worried about the sustainability of the annual migration. There’s so much information and misinformation floating around in the news these days about the causes of the monarchs decline. What I’ve tried to do in the book is outline the best knowledge that we have to date and to examine the facts critically, so we can really understand what might be going on. Unfortunately, we don’t have all the answers, but we can reject some of the most prominent explanations for the population decline of the monarch butterfly. As I argue in the book, planting milkweed certainly won’t hurt, but it is unlikely to save the monarchs annual migratory cycle. It is perhaps ironic that I spend eight chapters of the book discussing and detailing the importance of milkweed for monarchs, and nothing could be more true than their intertwined and intense evolutionary battle, but at this stage, and thinking about their conservation, it does not appear that milkweed is what is limiting the monarch’s population. Monarchs will persist for a very long time, but given that they are migratory butterflies that taste their way across North America, their declining population is something we must try to understand. Much more than the monarch is at stake, these butterflies are sentinels for the health of our continent!

Anurag Agrawal is a professor in the Department of Ecology and Evolutionary Biology and the Department of Entomology at Cornell University. He lives in Ithaca, New York. He is the author of Monarchs and Milkweed: A Migrating Butterfly, a Poisonous Plant, and Their Remarkable Story of Coevolution.