Monarch Butterfly  Migration

Migration News: September 22, 2006

The migration to Mexico is underway! Here is the news from the migration trail:

Resting on Monday in Monroe City, MO >>

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Highlights from the Migration Trail

Summer is over! A cold air mass swept across the continent last week, insisting that it's time for fall. People noted the "stop and go" nature of monarch migration during this dramatic change in weather. As these comments highlight, monarchs move during windows of opportunity and rest and refuel in between:

Central region:
Iowa, Indiana, Missouri and Kansas saw the most action:

9/20/06 Prairie City, IA
It was truly a surprise to see so many monarchs after days of rain and much colder weather. I suspect many had been delayed to the north by the bad weather.

9/18/06 Amana, IA
Sitting in the parking lot at work during lunch I counted 45 Monarchs in 25 minutes. All were trying to fly SW. They better hurry because the temperature is predicted to fall down to 30 F by Wednesday morning.

9/18/06 Kansas City, MO (39.10 N, -94.60 W)
I sat down and, for an hour, observed a wonderful flight - 175 monarchs. Most of them are sailing high above the rooftops and treetops, but a few have dropped down to feed on the flowers. As I write this at 11:10 am, I can see 5 in my yard now!

9/16/06 Monroe City, MO
I first noticed the monarchs on Saturday the 16th. The weather turned cooler late on the 18th and, the next day, the monarchs were gone!

Migration Rate Math

As the monarchs funnel toward Mexico their numbers overhead become greater and greater.

Here are observations we collected this week. Who will see the record flight for fall 2006? Let's see!

"We counted 37 butterflies in 15 minutes going over our playground at school."
Memorial Primary
Bluefield, WV

"Our class went outside at 1:10 and observed for 10 minutes..."
Atchison Elementary
Atchison, Kansas



Eastern region:
When a northwest wind hits the ridges of the Appalachian Mountains the air lifts upward. Monarchs can fly along the ridges effortlessly toward the southwest. Under such conditions came this...

9/15/06 Waynesboro, VA (38.03 N, -78.86 W)
It's difficult to adequately describe the most impressive flight I have ever witnessed. Not a single one here and one there, but clusters filled the sky, quickly moving through by the brisk NW winds, a continuous flow.

And from the Monarch's winter home in Mexico:

9/21/06 Angangueo, Michoacan, MX (19 N, -100 W) No monarch butterflies in sight yet... (Estela Romero has the whole community watching! >>)

This Week: Too Cold to Fly Today?

Monarch butterflies are in a race against time during fall migration. They must vacate the north before they're trapped by the cold. In order to fly, a monarch's muscles must be warm enough. In fact, if a monarch's thoracic (body) temperature is below 55 F (13 C) it can't fly at all.

This map shows how quickly temperatures drop as the fall season progresses. The days are rapidly getting colder (and shorter, too)! With each passing day, monarchs have a smaller and smaller window of time in which they can fly.

Keep track of temperatures in your hometown--and across the continent, too. When and where can monarchs fly today? >>

But wait...There's more to it!
Monarchs can raise their temperatures above air temperature by 1) basking in the sun and 2) shivering. Explore more!

  • Basking Behavior >>
  • Shivering Behavior >>

Watch how temperatures fall in the fall!

See: Too Cold to Fly Today?

First Symbolic Monarchs Have Arrived!

They're on the move. Almost 700 butterflies have already reached our staging grounds in Minnesota. We hope you'll be sending yours soon. Please include support for monarch conservation in Mexico!

Deadline to Migrate: October 13, 2006 >>

Teachers' Guide

The suggestions in this guide are provided to help teachers integrate Journey North's real-time program in the classroom.

The Next Monarch Butterfly Migration Update will be posted on September 29, 2006

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