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Monarch Butterfly Migration Update: September 24, 2004

Today’s Update Includes


Highlights From the Migration Trail

At last! The season’s first big wave of migration has finally occurred! A sudden rash of reports arrived as large numbers of monarchs apparently moved through southern Iowa, and on into Nebraska, Missouri and Kansas.

 

Click Map to Read Highlights Along the Migration Trail
(Mapping Suggestions)

09/20/04 Sergeant Bluff, IA
“There were hundreds of Monarchs roosting in the understory of the grove on the north side of the house. The monarchs have been arriving for the last 3 days.”

09/17/104 Creston, IA
“Finally!! Over 50 monarchs in our hackberry tree tonight. I've seen a few arriving late afternoons for about a week, but not enough to even find where they were roosting. They are a welcome sight.”

09/19/04 York, NE
“They're here! Where the alfalfa fields are blooming, there are butterflies! We haven't seen any roosting sites yet but the fields are showing Monarchs nectaring. We had a cold front move through last week but the last two days have been hot and windy with winds from the south over 20 miles an hour. The Monarchs are holding onto their flowers tightly!

9/20/04 Kansas City, MO
“While outside at Noon at Washington Park, Crown Center area in Kansas City, MO, I observed 10 Monarchs flying to the Southwest, within a 30 minute time frame.”


Interactive Maps: Read All Reports on the "MapServer"
All monarch sightings that have been reported are displayed on our MapServer. You can “click” to read each observer’s comments.
Peak Migration Sightings Sightings of Overnight Roosts

Migration Rate Math: Who Saw the Most Monarchs?
Dr. Calvert counts monarchs as they arrive at the sanctuaries in Mexico.
The observer in Kansas City watched her watch while she watched the monarchs. Thanks to her, we know butterflies were streaming by at a rate of 20 per hour. By calculating the migrate rate, we can compare one observation to the next.

When you watch for monarchs, follow her example. Record the number of monarchs you see AND the number of minutes you watched for monarchs. Then calculate the migration rate. For units, use monarchs per minute (or monarch per hour).

For practice, here’s a worksheet with examples from previous years. Who saw the most monarchs?
  • Migration Rate Math

    Challenge Question #7
    "Who saw the most monarchs? Arrange the observations in order, from the observer who saw the most to the fewest monarchs. In your answer, use standard units to compare the number of monarchs (monarchs/hour or monarchs/minute)."

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


Not All Go to Mexico: Utah Students Study “Western” Monarchs

Which monarchs go to Mexico?
Dots suggest areas of uncertainty.

Do monarchs east of the Rocky Mountains mix with those that over-winter on the California Coast? Are the Rocky Mountains truly a barrier monarchs between the two populations? If so, does the Continental Divide mark the line between the two populations?

For years, those questions have been debated. This week, we received a message from a Utah teacher whose students helped uncover some answers. Mr. Ron Hellstern of Byrum, Utah, wrote:

“My classes initiated the Intermountain Monarch Butterfly Project. We are associated with the Monarch Program of San Diego, and have helped them determine the winter migration destinations of Intermountain Monarchs.

“When we started this project back in 1994 there was little, if any, knowledge about the migration routes or roosts of the Intermountain Western population. My students helped to establish the baseline data, and recruit other schools along the western slope of the Rocky Mountains to assist in collecting this information.

"Thanks to some of our tags, our Monarchs have been spotted in Santa Cruz, California, which means these beautiful and delicate creatures cross the Great Basin Desert and the Sierra. Amazing!!! Our monarchs may not be going to Mexico, but we feel just as attached to them."


Which direction did the Utah monarch fly?

Try This!
  • Trace the course the Utah students’ monarch might have flown from Byrum, Utah, to Santa Cruz, California.
  • Can you find the Great Basin Desert? The Sierras?
  • How many kilometers did this monarch fly? How many miles?
  • Which direction did the monarch travel?
  • Find the Rocky Mountains on a physical map.
  • Can you also find the Continental Divide?
  • At various points in the Rocky Mountain region, predict where a monarch from this region might over-winter. Would it fly southward to Mexico or westward to the California Coast? Explain the reasoning behind your prediction.

Chasing Monarchs on Both Sides of the Continental Divide

"The 'Berlin Wall' model of monarch migration was based on assumption and repetition rather than fact," says Pyle.

Naturalist Robert Pyle traveled extensively on both sides of the Continental Divide one year during fall migration, watching for migratory monarchs. Whenever he found a monarch, he watched the direction it flew. Then he chased its invisible path until he found another monarch. All along the way, he interviewed the people he met and asked them when and where monarchs had been seen. His book, "Chasing Monarchs" chronicles his journey.

“By physically traveling with the monarchs, day by day, north to south, I hoped to shed a few lumens of light on several mysteries of the monarchs,” he said.

Do the Rocky Mountains truly form a barrier between the eastern and western monarch populations?

A basic assumption of North American natural history was based on thin evidence, concluded Pyle. The eastern and western monarch populations are not the distinct entities scientists have long assumed. Read his book and see his article in Orion magazine:


Watching and Waiting at the Over-wintering Sanctuaries in Mexico
Estela Romero and German Medina live beside the monarch sanctuaries in the mountain town of Angangueo, Michoacan, Mexico.

They have promised to report to us weekly as they watch for the first monarchs to arrive. No monarchs have been seen yet!

The Romeros have a small grocery store near the center of town. It’s fun to spend time in the store and watch members of this mountain community come and go. People visit all day long, buying everything from chile peppers to soap and fertilizer. The Romeros have everybody in the valley helping to watch for monarchs.
 
  • “Hola a todos los interesados una vez mas en la migracion de la Mariposa Monarca para el ciclo 2004-2005,” begins Estela Romero. (Spanish version)
  • “Hello to all people involved in the Migration of the Monarch Butterfly over the 2004-2005 season,” begins Estela Romero. (English version)

Meet German Medina and Estela Romero.
While the monarchs are in Mexico, German Medina uses this truck to take visitors up the mountain to see the monarchs. He carries Symbolic Butterflies to children in the same truck.
Estela Romero, shown here with her daughter Lara Emilia, is our translator. We're so lucky to have her help because nobody at Journey North speaks Spanish well!


Reminder: Symbolic Migration Deadline Oct 15
Only 21 more butterfly-making days before the Symbolic Migration deadline. Don't be late! Butterflies received after the postmarked deadline cannot migrate.
fall2002_0012  fall2002_0012  fall2002_0012 

How to Respond to Today's Challenge Question
1. Address an e-mail message to: jn-challenge-monarch@learner.org
2. In the Subject Line of the message write: Challenge Question #7
3. In the body of the message, answer the question above.

The Next Monarch Migration Update Will Be Posted on October 1, 2004.

Copyright 2004 Journey North. All Rights Reserved. Please send all questions, comments, and suggestions to jn-help@learner.org
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