Migration Update: September 24, 2009
Please Report
Your Sightings!

This Week's News:

Photos of the Week

Photos: Jim Gagnon
What tales do tagged monarchs tell?

The Migration: Maps and Questions

Fall Roosts


PEAK Migration


ALL Monarch
Migration Sightings


Distribution Map

Learn About Migration Maps


Make Your Own Migration Map

For Your Journal
This Week's Map Questions

Latest News

Thanks to Eastern Observers!
We begin with thanks to our observers in the East who are faithfully reporting monarch observations even though few have seen more than a monarch or two at a time and nobody has spotted a roost. Don't be discouraged! These observations are helpful and important. Together we are documenting what was truly a dismal summer breeding season. Please keep sightings coming, like these:

  • In Pennsylvania, Perkiomen Valley High School students watched for 1.5 hours: "We saw only one male who was very tattered with parts of the wing almost transparent from loss of wing scales." (9/21/09)
  • In New Jersey, Assumption Academy students watched for 40 minutes: "Four monarch butterflies were flying south and flew very close to the children." (9/21/09)
  • In New York, Mount Markham Central School students watched for 30 minutes:
    "MacKenzie saw a monarch at recess and it was fluttering. The class was out at noon."(9/16/09)

Clear Wave of Migration Moves into Mid-Atlantic States
Monarch biologist Dr. Lincoln Brower noted a clear change on Sunday when the number of monarchs increased dramatically at his home in Virginia. Other observers throughout the Mid-Atlantic states noted the same wave of migration:

  • "Migrants are finally here," Dr. Brower wrote from his home in Virginia. He counted 48 fresh monarchs nectaring at 2:40 pm on Sunday, and counted 56 monarchs at 2 pm on Tuesday. "I was beginning to wonder if we would have a migration this fall through the eastern side of the Blue Ridge, at our home." (9/20/09 and 9/22/09)
  • In Virginia, Spring Hill Elementary students sighted "one monarch definitely migrating southwest during lunch recess." (9/23/09)
  • In Virginia, Trinity Lutheran School students "noticed a beautiful Monarch flying around the flag pole during World Peace Day." (9/21/09)

Monarchs Traveling Unusual Pathway in Great Plains
Monarch roosts show us where there are large concentrations of butterflies, so roosts reveal the primary pathways the monarch population travels during migration.

"Holy cow!" exclaimed one monarch expert after seeing the most recent migration map. In an unusual turn of events, monarch roosts appeared last week across western Kansas, and even northwestern Oklahoma and Texas. This is nearly 200 miles west of the pathway the monarchs traditionally travel, based on data collected over the past seven years and shown on this live map. The monarchs are near the Colorado border, and are already west of the overwintering sites in Mexico. (Notice the location of the overwintering region, at longitude 100 W). Why are the monarchs so far west? Did the unusual east winds in the Central Plains over the past few weeks blow them there? Are they finding suitable habitat in this western landscape, which is typically quite dry? What will happen next? Will they continue to move westward, or will they drop down straight south into west Texas? Mountains, deserts, forests, and oceans also influence the monarch's traditional migration pathways. This fall, large numbers of monarchs are migrating where only a few monarchs are usually seen. Something is out of the ordinary!

  • Predict: Look at this migration map journal page and compare this fall's migration pattern to that in previous years. What pathway do you think the migration will follow across Texas and Mexico this year? Explain your reasoning.


Why so many male monarchs?
This roost formed on Tuesday night in San Angelo, Texas. "It seems the majority of monarchs in this shot are males," noted the observer. Should this be expected?"

Photo: Fred Alley

Compare Migration Pathways
You can continue to follow the migration on this live map. Compare this fall's migration pathways to those in previous years.


Nonfiction Reading: True Stories About Tagged Monarchs


Photo: Jim Gagnon

In this activity, students read true stories about tagged monarch butterflies. They explore what tagging reveals about monarchs and their amazing journeys. Each story provides a snapshot of migration, based on single monarchs that were tagged and recovered. Challenge your class to figure out what conclusions can be made from tagging and recovery data. Invite them to make hypotheses to explain unexpected findings. As a class, generate questions that motivate students to search for answers.

Links: Monarch Resources to Explore

Monarch Butterfly Migration Updates Will be Posted on THURSDAYS: Aug. 27, Sep. 3, 10, 17, 24, Oct. 1, 8, 15, 22, 29, Nov. 5...or until the monarchs reach Mexico!

The Next Monarch Migration Update Will Be Posted on October 1, 2009.