Monarch Migration Update: October 11, 2012
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The week's cold front ushered the migration across the border into Mexico, and sightings in the east continued at peak. How do temperatures affect fall migration? Monarchs are in a race against time. They must leave the north before they're trapped by the cold.

This Week's Update Includes:

Image of the Week
Monitoring the monarchs' arrival in Mexico
Watching and Waiting
News: Crossing into Mexico!
"The migration is definitely here!" announced Rocío Treviño who coordinates Mexico's migration-tracking program, Correo Real. She forwarded the first substantial report south of the U.S. border, a sighting on Monday of 50 monarchs in 30 minutes:

"With the arrival of Cold Front Number 5 to our beloved Mexico, the awaited monarch butterflies have arrived in Ciudad Acuna!"

Pulse Appears in Texas
At the same time, many observers reported a clear pulse arriving in Texas, where monarch numbers have been unusually low.

Gregg Lee was seeing only a few monarchs per day on nearly 10 acres of blooming Liatris. Things changed on Monday: "Monarchs were on every patch I checked, in some areas with one every 5 or 10 feet. A total of 500 is a safe estimate." 10/8/12 Chalk Mountain, TX

The pace picked up to 53 monarchs per hour in Keene, TX: "Most are flying above the tree tops, a few coming down to our yard to rest." 10/10/12 Patty Lockwood

Largest Roost in Texas
Only seven roosts have been reported so far from Texas, containing a total of 350 butterflies. Let's hope for more like the one on Tuesday night with its estimated 2,000 butterflies:

"It was a good crop of monarchs, in clusters by the dozens (2-4 dozen per cluster) on scattered tree branches in a small pecan grove," reported Genie Robinson from Brackettville.

Appalachians Peak
In the East, the excitement continued along the Appalachian chain:

"While on the playground to release a monarch we had raised, our class observed 21 other monarchs in flight. We just completed our Symbolic Monarch Migration packet. What a special day for this class of first graders!" 10/4/12, Knox Elementary, Canton, Georgia

While driving on North Carolina's Blue Ridge Parkway, Rachel and her 11 year-old daughter came upon a river of butterflies flowing at 400 monarchs per minute. "They were everywhere!" 10/2/12

Rocio Trevino, Correo Real
Reporting from Mexico
Image: Elizabeth Howard
Counting Cold Fronts
Servicio Meteorológico Nacional
Monarch butterfly nectaring on Liatris
Pulse Appears in Texas
Image: Gregg Lee
Largest Roost in Texas
Image: Genie Robinson
Monarch butterflies along Blue Ridge Parkway
They were everywhere!
Image: Rachel T.

News from Mexico: Monitoring Begins
Now that the migration has entered Mexico, Estela Romero has everybody watching for the first arrivals:

"After a long walk, we saw no trace of a single monarch, so Jocelyn and Roberto marked zero on the monitoring graph," Estela Romero reported on Monday from Angangueo in English and Spanish.

Monitoring the monarchs' arrival in Mexico
Slideshow: Too Cold to Fly?
Monarch butterflies are in a race against time during fall migration. They must leave the north before they're trapped by the cold. Monarchs are cold-blooded so, in order to fly, their flight muscles must be warm enough. Using the facts and photos in this slideshow, explore this essential question: How do temperatures affect fall monarch migration? See slideshow:


Tagging Monarchs: Tiny Tags, Big Discoveries
The Migration: Maps and Journal Page
Watch for monarchs that are flying in directional flight, resting at overnight roosts, or refueling at flowers in fields, gardens, or roadsides.


Seeing Monarchs?
Report Weekly!
When you see a monarch, we want to know about it.
Monarch Butterfly Migration Map: All Sightings, Fall 2012 Monarch Butterfly Migration Map: Peak Migration, Fall 2012

Journal: Too cold to fly?

All Sightings
(map | animation | sightings)
Peak Migration
(map | animation | sightings)
The next migration update will be posted on October 18, 2012.