|
Migration
Update: April 9, 2009 |
Please
Report
Winter Sightings! >> |
Today's Report Includes:
|
Dr.
Lincoln Brower, Sweet Briar College
What is this?
>> |
The Migration: Highlights,
Maps, and Questions |
Highlights:
The Stop-and-Go Nature of Monarch Migration
The
monarchs made a clear push into Oklahoma and Arkansas during the
past week. A strong south wind blew on Saturday and that single
day was responsible for the week's biggest push. Watch the animated
migration map and you can see the jump.
The
cause of last week's stop-and-go migration were two cold fronts
with a short break in between, when a warm front and south winds
allowed the monarchs to make some progress. You can see the location
of Saturday's warm front and south winds on the maps to the right.
The
migration entered only one new state last week. (Can you find it?)
This illustrates how little the migration advanced; instead, the
butterflies were filling in behind the migration's leading edge.
Remember, our map shows where observers saw the first
monarchs of spring. Following behind is a parade of
monarchs, millions strong and at least 1,500 miles long. (Last Wednesday
Estela Romero reported that there were still thousands of monarchs
at one of the sanctuaries as you'll read below.)
Field
Reports from Citizen Scientists: Who saw...?
Who
saw monarchs with fresh wings and why is this significant? At what
latitude are monarchs arriving where the milkweed is just emerging,
and what does that mean?
|
Weather
on April 4th
Notice
how the warm front stretched northward from Texas and into Oklahoma
on Saturday, where migration-watching was spectacular.
In the region below the warm front strong south winds were blowing
on Saturday.
Record
your predictions!
|
|
Hypothesize!
Which Way is the Migration Moving — and Why? |
This is a
fascinating time of the migration. Notice how far east
the monarchs have gone and how little they have moved to the north. Look
carefully at the migration map and find the overwintering sites in Mexico
at longitude 100 West. If the migration were traveling directly north
the monarchs' path would follow 100 W. What's causing the monarchs to
travel where they are? Before reading on, write in your journal:
|
Why
go northeast? >> |
Explore
climate and migration! >> |
The
orange arc on this map shows where monarchs would be now if they
had spread equally in all directions.
Why do they advance most quickly to the northeast at this time of
year?
|
What
effect do temperatures have on the pace and direction of migration?
Here
are migration and temperature maps over five years for you to compare.
Take a look! Compare this year to past years.
|
|
News
from Mexico: Some
Still at Sanctuaries on April 1st >> |
"I
was curious to see how many monarchs remained up in the sanctuaries so
I took a trip up to El Rosario," wrote Estela Romero last Wednesday.
Here are her photos and observations.
|
|
Please
Report Your Sightings! |
|
Links:
Monarch Butterfly Resources to Explore |
|
|
The
Next Monarch Migration Update Will Be Posted on April 16, 2009.
|