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Monarch Migration Update: April 13, 1999

Today's Report Includes:

Migration Surged Northward Last Week
As today's 48 new sightings show, last week was a good week to migrate!

Among the most surprising news:

  • A monarch in Maryland--just north of Washington, D.C.
  • Two sightings from Illinois on Sunday, April 11
  • Sightings from many new states, all in the past week!

Last Week

This Week

Compare this week's migration map to last week's, then see if you can answer these questions:

Challenge Question #25
"In how many NEW states were monarchs seen during the past week? What is the total number of states in which the monarchs from Mexico have now arrived?"

Challenge Question #26
"Can you think of 3 reasons why it might be risky for monarchs to travel so far north this early in the spring?"

How Far Did the Maryland Monarch Fly?

Challenge Question #27
"Assuming it flew from Mexico, how many miles did the monarch now in Maryland fly?"

(To respond to today's questions, please follow the instructions below.)

Wind, Weather and Migration
Why have migration conditions been so good over the past weeks?

Wintessing the Final Days of a Generation
Krahn Elementary School in Klein, Texas, created habitat for monarchs at their school: "We planted it for them--and they are really coming!" said third grade teacher Patty Perkins. "We know the monarchs from Mexico have arrived because of the vast numbers of eggs on our milkweed."

Last week, it seems Perkins watched as one monarch silently reached the end of the long trail:

April 6
"Today a tattered female monarch laid eggs on several milkweeds. She stayed for several hours and laid many eggs. This evening I found what appears to be the same butterfly dead. Do you believe she completed her mission from Mexico--and left us with the next generation to journey northward?" (
When Will the Children, Grand-children and Great-grandchildren Arrive?
The next generation of monarchs is now developing. If you live in the north, YOUR first monarch of the season may be the offspring of these Mexican migrants.

Depending on temperature, the time for development varies. But the typical number of days the monarch spends at each stage of development is:

Development Time of
Monarch Generations

Egg 3-5 days
Larvae 9-14 days
Chrysalis 8-13 days
Total 20-32 days

Let's consider April 6th as the peak date of egg laying for the generation that over-wintered in Mexico. (In reality of course, monarchs are now at different stages of development all across their range. This question is only intended to help estimate the timing of monarch generations.)

Challenge Question #28
"Using the numbers above, what is the PEAK date the adults of each generation will emerge? How many generations could live this year, if you assume the eggs of the final generation are laid before September 1? Finally, what is the name of the generation that would migrate to Mexico?"

Generation (Number and Name)

Peak Date
Adults Will Emerge

#1 Children of monarchs from Mexico  
#2 Grand-children of monarchs from Mexico  
#3 Great-grandchildren of monarchs from Mexico  
#4 Great-great-grandchildren, etc.  

(To respond this question, please follow the instructions below.)
Speaking of Eggs
Discussion of Challenge Question #21

In our March 30 update we asked, "How many eggs do you suppose one monarch can lay?"

"We found out that a monarch could lay up to 400 eggs. We found the information from Monarch Watch. We think that is a lot for such a little creature. There must be a lot of eggs that are eaten before they are hatched or caterpillars that don't make it to the butterfly stage because we don't see that many butterflies around."
Ferrisburgh Central School, Grade Three

How to Respond to Today's Monarch Challenge Questions

IMPORTANT: Please answer ONLY ONE question in each e-mail message!

1. Address an e-mail message to:
2. In the Subject Line of your message write: Challenge Question # 25 (or Challenge Question # 26, #27 or #28)
3. In the body of EACH message, answer ONE of the questions above.

The Next Monarch Migration Update Will Be Posted on April 20, 1999.

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