2007 Fall Migration

The 2007 Monarch Butterfly

Fall Migration is Underway!

During the next two months I will attempt to keep everyone informed about the Monarch Butterfly Fall Southward Migration.  I will begin each week by including some Monarch Facts followed by a weekly update including migration sighting maps and news available at http://www.learner.org/jnorth/monarch/News.html   These weekly updates clearly show the movement of the migration as it begins in the northern Canadian Provinces of Manitoba and Ontario, down the Ohio Valley and New England, eventually finding its way through New Jersey,, down the eastern seaboard, through the heart of the deep south, across the gulf coast States of Mississippi, Alabama, Texas, crossing the border into Mexico and ending on or about November 1st in the State of Michoacan, Mexico high up 10,000-12,000 feet above sea level in the Trans-Volcanic Range in Central Mexico, just hours outside of Mexico City. 

Imagine this... These Monarchs have never been to Mexico.  They are the great-great-great grandchildren of the Monarchs who overwintered in Mexico last year.  Yet... somehow, something tells them to stop mating in late August and early September and their instinct tells them to begin flying south to a place they have never been before, but to where their every 4th to 5th generation has gone for thousands of years, back to the earliest know settlers of central Mexico at Teotihuacan.  It is truly an amazing mystery as to how the Monarchs are able to fly in some cases over 2,400 miles across a continent to a place they have never been. 

Scientists believe that the Monarch's instinct is fueled by the fact that during the fall in the northeast and in eastern Canada, the days are getting shorter, and cooler.  The Monarch food supply is decreasing; flowers are dying back, milkweed that the Monarch butterfly lays its eggs on begins dying due to the shorter days and cooler nights.  The Monarchs begin flying south in search of flowers to nectar on.  As they descend on the southern Gulf States, their numbers grow as they begin descending into Mexico. 

Why Mexico?  Scientists believe that the elevation coupled with the fact that they Endangered Oyamel Fir trees that the Monarchs use to roost in Central Mexico strike a perfect balance of humidity and temperature that allows the Monarchs to live off of their stored fat reserves from nectaring along their fall migration route.  It is not artually warm in the sanctuaries though.  Given the fact that the mountains there are 10,000 - 12,000 feet above sea level the winter can bee extremely cold, they even have rare snow and ice storms.  One such storm in 2004 killed over 80% of the North American Monarch population that year.  It took many years for the numbers to recover to the point where they were last winter, a record setting winter as far as scientists are concerned.

After overwintering in the mountains of Michoacan the Monarchs begin mating in the Sanctuaries in early March as the weather warms, they then begin their northward migration, maybe making it as far as Texas, where the female lays between 300-700 eggs, one at a time on the leaves of milkweed plants.  After she lays her last egg the female Monarch dies and then that tiny egg, only a size of a pinhead takes 3 days to hatch.  The caterpillar that emerges from the egg, within 10-14 days eats the milkweed plant growing 3,000 times in size.  When it is done eating the caterpillar rests by shedding its skin, turning into a chrysalis, where it rests for another 10-14 days as the cells re-arrange inside, eventually releasing a beautiful Monarch Butterfly.  We call this a complete metamorphosis... egg - larva (caterpillar) - pupa (chrysalis) - butterfly.  

This metamorphosis repeats itself at least 4 to 5 times during each summer in the life cycle of the Monarch butterfly.  Each summer Monarch generation goes through this 30 day cycle only to live two weeks, mate and die.  This last August/September Monarch is special though.  It does not mate and die and live 2 weeks.  It gets to migrate, therefore allowing it to live for 8-9 months.  Without this migrating generation, there would be no Monarch butterfly.  They are responsible for carrying on the species.  This is why we monitor the fall migration so closely, and why scientists are concerned enough to tag Monarchs and monitor tag recoveries.

The Monarchs arrive in Mexico on or about November 1st, also the day that the Mexican people celebrate "Dia de los Muertos" or "Day of the Dead", also know in Christian calendars as "All Soul's Day".  Mexicans strongly believe that the Monarchs that arrive this time of year are the souls of their departed loved ones.  To celebrate their return Mexicans put out symbolic offerings, adorn altars in their homes with photos of their departed loved ones next to photos of religious symbols and icons.  They also put out food and drink that was a favorite of their dead family member as well as a bowl of water for the returning Monarchs to symbolically drink from. 

As you see, Monarch butterflies are not only insects, they carry a long legacy of connecting 3 nations; Canada, the United States and Mexico.  They also symbolize a re-birth to the Mexican people as well as are worldwide symbols of peace and understanding and beauty.  Monarchs are also symbols of an indomitable spirit that allows them to migrate extremely long distances over very rough terrain to a place they have never been before.   

Please enjoy these next few months, before you know it will be November, all the North American Monarchs will already be in Michoacan and the long cold winter will set in here, as we patiently await the news in March of the first word out of the Sanctuaries that Monarchs are beginning to move down the mountain on the warmer days and eventually out of places like Sierra Chincua or El Rosario or Pelon toward the U.S. border.

So please sit back and let's follow the migration together while learning a new appreciation for an old friend we may have only once seen in passing but who we have begun to learn and respect...

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