• This Week's Migration Map and Data
• News from the Migration Trail
• Time to Revisit Views About Monarch Migration? Scientists Comment
• Do Only Females Migrate? Please Contribute Your Observations
• The Life Cycle Continues: Ms. Monarch's Final Days and Her First Chrysalis
• Over 750 Eggs! What Happens to Them All?
• Monarch Larva Monitoring Project: You Can Help With Research!
• First a Monarch Eats its Shell and Then...Discussion of CQ #10
• How Much Would You Weigh? Challenge Question #11
• Speaking of Eggs: A Conversation With Dr. Lincoln Brower
• Noticia de la migracion de la mariposa monarca
• Symbolic Butterflies to Fly on Earth Day (April 22, 2006)
• Please Report Your Sightings!

Use today's data to make your own map, or print and analyze our map:

• Migration Map
• Migration Data for Classroom Mapping
• Slideshow (Week-by-week animation)

Thanks to everyone for contributing! There are 55 new sightings on this week's map.

The migration's leading edge has now advanced to 39N, far beyond its position at 36N just one week ago.

• How many miles is that?
• How many miles per day did the migration advance, on average? (Assume 69 miles for every degree latitude.)
• If they continue at this rate, predict when the first monarchs will reach you.
  

This is an unusual year! Monarchs overwintered as far north as Virginia and began appearing inland in early spring. Is this significant? Biologists Andy Davis and Dr. Sonia Altizer of the University of Georgia shared their thoughts:

"We are not aware of previous studies documenting this high number of sightings, and these reports may stimulate scientists to revisit common views of monarch migration and overwintering behavior," they began.

• Time to Revisit Views About Monarch Migration?
  

• What have you observed? Please contribute your observations

The Life Cycle Continues...
Ms. Monarch’s Final Days and Her First Chrysalis

"Well the day finally arrived..." Dr. Edson wrote sadly at noon yesterday. After laying a grand total of 758 eggs, Ms. Monarch's life finally came to an end.

Special thanks to Jim Edson for sharing Ms. Monarch's story with us! He faithfully counted her eggs every day at noon for over a month, and gave us new insights about the monarch life cycle. Thank you, Jim!

But the story is not over, he reminds us: "Now we wait for the first butterfly," he said on Sunday, the day Ms. Monarch's first child became a chrysalis. Soon her children will continue the journey north. Get ready to watch for fresh-winged butterflies!

• Ms. Monarch's Egg-laying Calendar
• Monarch Growth Calendar

Thank you
Dr. Edson!

Survival is not easy. "Only about 10% of monarch eggs make it to the 5th instar," concludes Dr. Karen Oberhauser, based on data collected by her volunteer network, the "Monarch Larva Monitoring Project."

This means 90% die before they even become a chrysalis! Exactly what do monarchs need to survive? What threats do they face? Begin with an egg and keep a list. We've started with three needs, all drawn from today’s update (Read on...)

• Keeping a List of a Monarch's Needs

Volunteers are invited to participate in Dr. Oberhauser's research this spring and summer. Her project is gathering important information about monarch biology.

• Monarch Larva Monitoring Project: You Can Help With Research

Last week Dr. Brower said, "Monarchs have to be careful not to lay more than one egg per plant (or leaf) because, when they hatch, the caterpillar will eat its own eggshell. The next thing it will do is wander over and___."

"Eat the milkweed plant," said Amanda S. She is so right! Monarchs eat a tremendous amount of milkweed. In fact, a monarch increases in mass by 2,000 times while it's a caterpillar. This amazing change takes place in only about 9-14 days. Imagine gaining weight the way monarch larvae do!

Challenge Question #11
"How much would you weigh if your weight increased 2,000 times? With your answer, name something that weighs the same amount."

There is another reason female monarchs usually lay one egg per leaf or plant. Listen to Dr. Brower. You are sure to be surprised. He watched monarch eggs closely and here is what he discovered:

• Speaking of Eggs: A Conversation With Dr. Lincoln Brower

As the butterflies fly over your homes, schools and cities, we're sending the news back to the students in Mexico so they can track the migration too. Here is this month's report in Spanish, with an English translation:

• Noticia de la migracion de la mariposa monarca: 1 abril de 2006
• Monarch Migration Update: April 1, 2006

We can't track migration without your help!

• Please Report Your Sightings