Monarch Butterfly Monarch Butterfly
Today's News Fall's Journey South Report Your Sightings How to Use Journey North Search Journey North

Monarch Butterfly Migration Update: August 29, 2003

Today's Report Includes:

Welcome to Journey South's Migration Season!
Our lives take a turn in the fall. Across the north, summer's long days shorten rapidly and temperatures drop. Meanwhile, millions of children return to school. Their year will be spent learning skills needed during the long human life span.

At the same time, a magical event takes place in the animal world. Perhaps traveling over your own head right now--or clustered by the hundreds in a nearby tree--the annual monarch butterfly migration to Mexico is underway.

It's such an unlikely story! As if autumn leaves could arrest their fall, point southward, and float all the way to Mexico. The butterflies are born knowing everything they need to survive, so we look on with wonder:

  • How do they know which direction to go?
  • How fast and how high can they fly?
  • How long does their journey to Mexico take?
  • And how do the monarchs know when they've found their destination--a small speck on the planet where none has ever been before?

Come travel with the monarchs as we explore questions like these. In the weeks ahead, we'll see what scientists know about these mysteries, and how much more there is to learn.

Highlights From the Migration Trail: Northern Monarchs Begin the Journey

Click Map to Read Highlights Along the Migration Trail

The first overnight roosts are now being reported from the northern reaches of monarch breeding grounds. Patient observers there who keep an eye skyward can see a southbound monarch drift across the sky every few minutes.

Here are comments from some observers:

  • As early as August 3rd, thousands of monarchs were poised on Canada's southern border at a major roost in Saskatchewan.
  • About 200 miles further south, monarchs began to gather in Little Falls, MN on August 13. "Each day more and more new arrivals apparently replace those that have moved on."
  • A student visiting Toronto, Ontario, reported thousands of monarchs roosting in the trees there on Monday, August 18. It was even on the local news. Toronto is located on the northern shore of Lake Ontario, so monarchs commonly bunch up there before attempting the long, over-water crossing.
  • At any overnight roost, the number of visiting monarchs tends to rise and fall from one night to the next. Mr. Paul Viger counts monarchs daily at his site in Campbell, Minnesota. The first 18 butterflies appeared on August 17 this year and numbers had climbed to 82 butterflies as of August 27. Take a look at the data he collected during the Fall 2001 season. What relationship do you see between wind and migration? Why do you think monarchs behave this way? See: Analyzing Data From a Fall Migration Roost
How many tagged monarchs can you see at this roost?

Teacher Tip: How to Map the Monarch Migration
How much class time does it take to map the monarch migration? Fourth grade teacher Dave Kust spends anywhere from 5 minutes to 5 hours a week, depending on his goals. Here's a recent interview:
Mexico's monarch sanctuaries are west of Mexico City, at 19N, -100W.
Which Way to Mexico?
Monarch butterflies are born knowing the way to Mexico--do you? Guess which way they should fly from your home town. Then use an atlas and compass to find out if you're right. Measure the distance to the Mexican monarch sanctuaries, then make a road sign in your classroom that points the way to Mexico and reads "This Way to Mexico: ___ Miles"
How Do Monarchs Know the Way to Go?
Observing the Sky Like a Butterfly

The first step in the long journey to Mexico begins by going in the right direction. Knowing the correct direction to travel is called "orientation." Monarchs orient by 1) knowing what time it is and 2) watching what the sun does during the day. Scientists call this inborn knowledge a "time-compensated sun compass."

It's easier to understand monarch orientation if you observe the same cues monarchs use while they travel. Here's how: On a sunny day, go outside with a compass, some stones and a long stick. Once every hour, place stones on the stick's shadow. Collect your observations exactly one hour apart at least 2 times. Then answer Challenge Question #1:

Challenge Question #1:
"Even though they don't have the words to say it, what do monarchs instinctively know about time and direction? (Complete this sentence.) The sun appears to move across the _____ (northern/southern) half of the sky from ___ to ___ at a rate of ___ degrees/hour."

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

Photos Courtesy of Dave Kust

Challenge Questions: A Central Tool for Student Learning
Journey North provides "Challenge Questions" in each weekly monarch update. Challenge Questions model the thinking/questioning process that scientists use in their work. For more information and suggested classroom use see:

Can you see the monarch egg?
Monarchs Are Born Knowing How to...
As you learn about monarchs during the school year, keep a list of everything monarchs are born knowing how to do. For fun, compare the age at which humans learn to do the same things. Just think: All that information is carried from generation to generation inside an egg that's smaller than the head of a pin!

Report Your Sightings
Please Report Your Sightings 
Please Report Your Sightings!
Remember: We can't track migration without your help. Please come to the web and share your observations. Thanks for your help!
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 #1
3. In the body of the message, answer the question above.

The Next Monarch Migration Update Will Be Posted on September 5, 2003.

Copyright 2003 Journey North. All Rights Reserved.
Please send all questions, comments, and suggestions to
our feedback form

Annenberg Web SiteToday's News Fall's Journey South Report Your Sightings How to Use Journey North Search Journey North Journey North Home Page