Journey North Monarch Butterfly Spring 2003

Monarch Butterfly Migration Update: March 21, 2003

Today's Report Includes:

Sudden Wave of Migration Crosses into Texas
The BIG Unanswered Question: Where Did the Monarchs Come
rom?
You’re the Scientist: How About the Florida Observations?
Challenge Question #11
Field Notes from Mexico: Millions of Monarchs Yet to Come
Predicting the Path of the Monarch's Spring Migration
Challenge Question #12

Sudden Wave of Migration Crosses into Texas

What a week! Rigth on cue, 41 one sightings flew in during the last week as if responding to Harlen Aschen’s command, "We are awaiting the first northbound monarchs returning from Mexico this week."

This week’s migration map shows monarchs already as far north as Dallas/Ft. Worth, Texas. (Special thanks to Mike Quinn of Texas Monarch Watch for reporting widely from his state again this spring.)

Link to this week's migration data. (Use the data to make your own migration map, or print and analyze our map.)

The BIG Unanswered Question:
Where Did the Monarchs Come From?
When the first March monarchs are sighted in Texas, there’s always a question: Did they truly coming up from Mexico or were they monarchs that remained in the U.S. during the winter? The latter are indicated by red triangles on our migration map. They are designated as “winter sightings” because the monarchs were sighted in January or February. So what happens when spring arrives?

Are Texans seeing butterflies from the sanctuaries in Mexico?
And/or are some of the monarchs the locally breeding butterflies?
Are the individuals coming up from Mexico the only ones that migrate?
Or do the locally breeding butterflies shift and become migratory, too?
Do butterfly numbers to go up so suddenly because the monarchs from Mexico are arriving and/or because the local butterflies are producing a new generation?

Short of sacrificing the butterflies for chemical analysis, observers watch for clues such as the following, but these are inconclusive:

The condition of the monarch’s wings. (Worn and faded wings indicate a long-lived butterfly, presumably having over-wintered in Mexico. Fresh, new wings indicate a newly emerged butterfly, from the local population.)
Clear and purposeful flight in northerly direction
The sudden abundance of adult butterflies
The sudden abundance of monarch eggs and then larvae

You can read comments in the database to see how observers discuss these issues. And now consider this:

You’re the Scientist: How About the Florida Observations?
Another fascinating region to consider is the Florida panhandle. Here are comments from Richard RuBino, who has been tagging monarchs there for almost a decade:

“We saw our first springtime monarch last Sunday, March 16th. This is the earliest I've seen a monarch in Tallahassee in the four years I've been working on spring migration projects.” Richard spotted a second monarch, “a well-worn female with faded wings” two days later. And a third monarch was seen on the 19th at the St Marks National Wildlife Refuge, about 25 miles south of Tallahassee on the coast.

Challenge Question #11:
"Where do you think the Florida panhandle monarchs came from? If migratory, describe the path you think the butterflies followed during migration. Defend your hypothesis, whatever it is. Give facts to support your reasoning."

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

Field Notes from Mexico: Millions of Monarchs Yet to Come by Dr. Bill Calvert

Copyright Dr. Lincoln Brower, Sweet Briar College

"Cool sunny weather and lots of activity...A blizzard with butterfly snow being driven horizontally, or even upward...A ticker-tape parade where the particles are multicolored orange, black, and white. The shadows of the butterflies move continuously across the ground before you...

"The colonies don't look any smaller, and it’s hard to notice that the butterflies are leaving,” reported Bill Calvert this week. “But during the next two weeks, all that are here presently--tens of millions--will be leaving. They’ll be totally gone in two weeks.”

Bill and his traveling companion, Jim Edson, are about to bid adios to the remaining monarchs in Michoacan. They’ll hop in Bill’s van and travel north beneath the butterflies. “Along the route north of the colonies we expect to see many, many monarchs passing by,” said Bill. They may put 1,500 miles on the van as they criss-cross the 900 miles back to Austin, Texas. Bill has promised to try to call in from the road next week, and tell us about the terrain the monarchs are crossing. Pull out your map of northern Mexico and see if you can find the route Bill describes in today’s report.

Field Notes from Mexico by Dr. Bill Calvert

Predicting the Path of the Monarch's Spring Migration
As the monarchs pour out of Mexico this spring, we're watching them spread across Texas. Where do you think they will appear next? New Mexico? Oklahoma? Arkansas? Louisiana? (You might be surprised!)

Print out the blank migration map below and draw the course you think the migration will take. Then record the names of the states where you think the butterflies will appear 1st, 2nd, 3rd, 4th, 5th etc. on your Migration Route Prediction Chart.

Challenge Question #12:
"Send your list, in order, of the 15 states where you think the monarchs will appear next. Why do you think the migration will travel in the direction you predicted? Explain your reasoning!"

How to Respond to Today's Challenge Questions:

IMPORTANT: Answer only ONE question in each e-mail message.

1. Address an e-mail message to: jn-challenge-monarch@learner.org
2. In the Subject Line of your message write: Challenge Question #11 (or #12)
3. In the body of EACH message, give your answer to ONE of the questions above.

The Next Monarch Butterfly Migration Update Will Be Posted on March 28, 2003