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Monarch Butterfly Migration Update: October 31, 2003

Today’s Update Includes:

Highlights From the Migration Trail

Click Map to Read Highlights Along the Migration Trail

"¡Las primeras mariposas han llegado!" came the word late last night from Angangueo, Michoacan. The first butterflies have arrived!

Our friend, German Medina, sent a fax to say that the monarchs have begun to arrive in the sanctuary area. Already, there are 25 trees filled with butterflies in the El Rosario Sanctuary, and 20 trees in the Sierra Chincua Sanctuary. School children who are monitoring the arrival beside the sanctuaries saw:

  • Three butterflies during a 5 minute count (Escuela Pedro Ascencio, beside the Sierra Chincua sanctuary)
  • Ten butterflies in 5 minute count (Escuela Los Trojos, near the El Rosario Sanctuary)

People in town are also beginning to see them. German's wife happened to look up while leaving her house. She caught sight of the monarchs and counted 70 butterflies in a 10 minute period.

¡Bienvenido a México!
The Finish Line
Mexico's Monarch Butterfly Sanctuaries

The Value Negative Data
Discussion of Challenge Question #11

For 5 weeks, students beside the sanctuaries watched for the monarchs to arrive. They recorded zeros every single day as they waited. Challenge Question #11 asked why it was so important to record the zeros. Mrs. Swentzel's third grade class in New Jersey knew: the zeros assured us that the students were watching!

This example shows why "negative data" is so important. We know we caught the monarchs' true arrival only because the students gathered zeros so patiently. Imagine a line graph with 35 days of zeros. When the monarchs finally arrived this week, the line would spike upward.

Noticias del avance de la migración en México
Writing from Saltillo, Coahuila, Señora Rocio Trevino of Correo Real received reports this week from as far south as Querétaro, Querétaro. “There were very few, approximately 5-6 per minute.” Very few! Imagine the numbers they must expect to see as the monarchs pour overhead! How many more miles do these butterflies have to fly? Measure the distance from Querétaro, Querétaro to Angangueo, Michoacan.

The United States of Mexico: Discussion of CQ #13
There are 31 states in Mexico. The capital, Mexico City, is in the "Distrito Federal" (Federal District), like Washington, D.C. How many states can you name before reading this list?

The area in red measures over 9 million square kilometers.

Like Finding a Needle in a Haystack?
Stop and think for a minute. The over-wintering sites are a tiny speck on the planet. This map shows the HUGE area in North America the monarchs migrate across on their way to the sanctuaries.

The area in red measures over 9 million square kilometers! In contrast, the sanctuaries are clustered within a region that measures only 800 square kilometers. This means that the monarchs find an area that is more than 11,000 times smaller than the area they migrate across. The monarchs certainly must know where they’re going!

Try This!
Make a migration trail, to scale, on your school's football field so you can visualize the monarch’s feat. A teacher from Austin, Texas wrote, "We make large butterfly wings and reenact the migration on our playground/field with signs for Canada, Austin, and Mexico."

Calculate the area of a standard football field, then name an object that is 11,000 times smaller than a football field.

Dr. Calvert watches monarchs arriving at the sanctuaries in Mexico.
Crossing the Narrow Finishing Line: Challenge Question #14
Last week Dr. Calvert described the migration route through northern Mexico. When the monarchs are flying in from the north to find the overwintering sites, he explained, they must strike the Transvolcaninc Belt within a 1.1 degree window. This means they fly across the continent to find a finish line that’s only 73 miles wide!

Challenge Question #14:
"Name a town that is 73 miles from your home town, so you can visualize the width of the migration’s finish line."

(To respond to this question, please follow the instructions below.)

Dias de los Muertos, Monarchs and Mexican Legend
When you are sleeping this weekend, many people in Mexico will be wide awake commemorating the "Días de los Muertos" (Days of the Dead). Rooted in the ancient Aztec tradition, and blended with Christianity, the holiday is a mix of customs and beliefs. The Mexican people honor and remember their ancestors, whose souls are believed to return to earth each year at this time. Some people spend the night at the cemetery, beside the graves of their loved ones.

Rather than a time to mourn, this holiday is viewed as a time to remember. Only when we forget them, does a person really die, it’s said. Gifts and favorite foods are left for the returning souls on special alters called "ofrendas."

In the monarchs' mountains of Michoacan, some say the returning monarchs represent their ancestors’ souls, because the monarchs arrive each year at the time of this fiesta.

An even older tradition connects monarchs with the corn harvest. In the native language, Purepecha, the name for the "monarch" is the "harvester." This is because monarchs arrive each fall when it’s time to harvest the corn. For hundreds of years, the sight of the monarch told the native people that the corn was ready for harvest.

Making "Pan de los Muertos" with the Moreño Family
By Elizabeth Howard
The Moreño family shares their mountain home with the monarchs. You can see the El Rosario sanctuary on the mountain beyond their house. One November, Dr. Bill Calvert and I visited as the family was preparing for the Días de Los Muertos. Señora Moreño was baking special loaves of bread called "pan de los muertos" (bread of the dead) in her wood oven. We hope you’ll enjoy your visit!

Visiting a Cemetery on Dia de los Muertos
For days leading up to Dia de Los Muertos, people are seen in the streets on their way to the cemetery. (See photos and Dia de los Muertos links.)

How to Respond to Today's Challenge Question
1. Address an e-mail message to:
2. In the Subject Line of the message write: Challenge Question #14
3. In the body of the message, answer the question above.

The FINAL Monarch Migration Update Will Be Posted on November 7, 2003.


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