Monarch Migration Update: Sept. 8, 2011
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Your Sightings!

The first strong cold front of the season sent monarchs sailing this week. Hungry monarchs stopped to feed from flowers as they traveled. This week, explore why nectar is so important to monarchs during fall migration. What concerns does Dr. Brower have as the monarchs approach drought-stricken Texas?

This Week's Update Includes:


Image of the Week

Dr. Lincoln Brower

Happy Birthday!

News: Into Iowa and Nebraska!

Nebraska Boy Notices First
A surprisingly early roost was reported in Nebraska on Saturday by Jerri Haussler in Hastings:

"My grandson was out swinging in my backyard about dusk. 'Nana, there are lots of butterflies!' he hollered. I went out and my gaze followed several flying around and landing in my tree limbs overhead. We watched for about an hour until it was almost dark. As I looked at the pictures and counted butterflies, I realized there were probably 1,000 monarchs!"

Early and Late?
The Nebraska roost of 1,000 monarchs is about two weeks earlier than roosts typically occur in the southern part of that state. Meanwhile, people to the north are reporting fewer and smaller roosts than in previous years.

"The migration is later than last year," observed Canadian monarch expert Don Davis. "I wonder if the late, cool, wet spring slowed monarch development and caused the migration to be later. Certainly numbers are way down from last year."

Eat, Stay, Leave
As monarchs travel to Mexico from flower to flower, imagine the places they stop along the way:

"We have a special butterfly garden to attract butterflies," report students in Midland, Michigan. A monarch stopped by for a meal this week, to everyone's delight.

"Monarchs have been sailing in the Oklahoma air for the past two weeks," say 5th graders at Council Grove Elementary, where monarchs also sipped some nectar.

"The monarchs that I captured in the clover field last night had VERY plump abdomens," observed Don Davis.

When this week's cold front reached Texas, many people reported their first fall monarchs. Near Abilene, "The monarch arrived on the wings of a blue norther and was looking for nectar sources along Deadman Creek."

Drought and Migration
In just a few weeks, the entire migration will travel through Texas where drought conditions are severe. (See map.) We asked Dr. Brower how the drought might affect the butterflies:

"As monarchs migrate through Texas and northern Mexico on their way to the overwintering sites, they spend considerable time building up their fat reserves by drinking the sugar-laden nectar from wildflowers. By the time they reach the Mexico overwintering sites, this sugar is converted to fat and the bodies of the butterflies are practically butterballs. To fuel winter survival and the migration back into the US the following spring, the butterflies gradually draw down these fat reserves. I am extremely concerned that the terrible drought this year in Texas and northern Mexico will have such a negative impact on the wildflowers that the butterflies will have a rough time building up their fat reserves and many more than usual will die of starvation."

Counting Cold Fronts
This week's strong cold front reached all the way to Mexico. Because it was Mexico's first cold front of the season, meteorologists there named it "Cold Front #1." Why do Mexican meteorologists count and name cold fronts? What do cold fronts have to do with monarch migration? This week, explore a weather map from Mexico and take a global view of our changing seasons.

Monarch Butterflies at roost site in Mexico.
Nebraska's First


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A Nectarivor Eats Nectar
A Nectarivore Eats Nectar




Drought and Monarch Migration
Drought and Migration



Weather map of Mexico
Counting Cold Fronts

Slideshow: Nectar and Migration: Finding Fuel Along the Way

Why is nectar so important to monarchs during fall migration? The facts and photos in this slideshow explore that essential question.




Slideshow: Nectar and Monarch Migration


The Migration: Maps and Journal Page
Monarch Butterfly Migration Map: All Sightings, Fall 2011 Monarch Butterfly Migration Map: Fall Roosts, Fall 2011 Migration Questions: Week 2

All Sightings

(map/ sightings)

Fall Roosts


For Your Journal
This Week's Question

Seeing Monarchs? Please let us know!

The next Monarch Migration Update will be posted September 15, 2011.