Monarch Butterfly Update: May 12, 2011
Please Report
Your Sightings!

Sailing on south winds, monarchs advanced dramatically during the past week. The migration entered 8 new states and our first Canadian province. Go monarchs! This week, compare a moth's migration to the monarch's. What can we learn from the corn earworm?

This Week's Update Includes:


Image of the Week

Temperatures were much colder this week than last week.

How Do You View a Dandelion?

News: Alien Crosses into Canada; Identified as D. Plexippus

This news just in from Canadian monarch expert, Don Davis:

"Please be informed that on May 7th, the Canadian border services and CSIS (Canadian Security and Intelligence Service) were alerted to the fact that one D. plexippus had crossed the border into Canada. Just as the RCAF was preparing to scramble their jets, the red alert was cancelled and the intruder was identified as a friendly alien. A statement released by our newly elected Prime Minister Stephen Harper indicates that all such further arrivals will be most happily welcomed across the land!"

Creative Writing: Make the News!
Write a newspaper article to announce the arrival of the first monarch in your hometown. Be creative! (See Journal Page.)

Monarchs Blast Past Latitude 40N
Look at them go! Butterflies broke beyond that latitude 40N barrier across the land, from Nebraska to New York. One jumped all the way to Minnesota, to almost 45N. (See animated map.)

"Scattered" is one word to describe the location of this week's 39 sightings. First-of-the-year monarchs were reported from 17 different states and 1 Canadian province. When the new generation appear in full force, sightings won't be so few and far between.

From Mexico or First Generation?
Where are the monarchs coming from? Those that overwintered in Mexico would be nearly 9 months old by now, so we don't think many are around. Could a Texas-born butterfly possibly be in Minnesota already, for example? Let's think it through:

  • The first report of a 1st generation monarch came from Texas on April 16th.
  • The Minnesota sighting was on May 10th, 24 days later.
  • It's 1,100 miles from Texas to Minnesota.
  • If the monarch flew __ miles per day, it could make it from Texas to Minnesota.
  • If the monarch flew in 25 mph wind, it could fly 1,100 miles in ___ hours.
  • Over 24 days, the butterfly would have to fly for ___ hours per day.

What do you think? Are these flight speeds possible? (Click here to check our math.)

Whoosh! There's That Pattern Again
This temperature map shows a typical day last week. See the bulge of warm air that stretches across the Central United States, from Texas to the Dakotas? Strong south winds were pumping that warm air northward. This wind map shows the pattern. On the ground, here's what an Iowa observer noted:

May 10: Hartley, Iowa
"Saw our first adult Monarch (looking frazzled) today! The wind has been extremely high from the south and south east the past couple days (over 35 mph) and they blew in!"

By the way, these wind maps only show conditions on the ground. The wind is stronger up high where the monarchs can fly.


Did You Know?
The monarch's scientific name is Danaus plexippus.

Animated Monarch Butterfly Migration Map





Wind map


Temperature Map

There's That Pattern Again

Feature: What Can We Learn from the Corn Earworm?

Meet Helicoverpa zea, a moth called the "corn earworm" in its larval stage. You may have encountered a corn earworm larva while eating corn-on-the-cob. Does this larva look familiar? (See picture.) Hungry corn earworm caterpillars cause extensive crop damage, so they are dreaded by farmers. Like monarchs, corn earworms are unable to survive cold, northern winters. In the spring, the moths begin to migrate north from the southern U.S. states. Scientists are monitoring the moth's migration the way we are watching monarch migration. Using weather maps, the scientists make forecasts to predict when and where this damaging insect will appear.

The Adult Moth

Images: Wikipedia

Corn Earworm Moth Stage Larva The Larva
Eating Corn
Weather and Migration

What can you learn about monarch migration from moth migration? Check out Tuesday's insect forecast map for corn earworm migration:

  • See how closely the "insect source region" (brown) matches our monarch source region, where first generation monarchs are now emerging.
  • Read how to weather systems create an "insect pump" that carries moths northward.
  • Notice how quickly the corn earworm is predicted to migrate from Texas into the regions shown.
  • Follow daily insect migration forecasts to learn how insect scientists and meteorologists describe weather conditions.

Insectforecast Website

Insect Forecast Map
Tuesday, May 10


The Migration: Maps and Journal Page
Pre-migration map: Winter monarch butterfly sightings (January or February) Map of milkweed emergence: Spring 2011 Journal Page
Make the News!

Let's find out when and where monarchs and milkweed appear this spring.

Annual Evaluation: Please Share Your Thoughts

Please take a few minutes to complete our Annual Evaluation. With your help, we can we document Journey North's reach, impact and value. Thank you!

The next Monarch Migration Update will be posted on May 19, 2011.