Monarch Migration Update: November 4, 2010
Please Report
Your Sightings!

"The monarchs are truly arriving now," exclaimed Estela Romero on Tuesday from her hometown of Angangueo. Tens of millions of monarchs are flying toward the region now, on time for their traditional arrival. What makes this region so special for monarch butterflies?

This Week's Update Includes:


Image of the Week

What holiday are Mexicans celebrating when the monarchs arrive?

What holiday are Mexicans celebrating when the monarchs arrive?

News: Monarchs Arriving in Large Numbers Now

"Throughout town we can see butterflies flying overhead today. My camera could not catch them, they were flying so high!" wrote Estela Romero on Tuesday.

As the monarchs arrive each November, the Mexican people are celebrating the Day of the Dead (Dia de los Muertos) to honor the lives of their ancestors. This week, Estela takes us to the alter (ofrenda) of a family friend, to a town celebration, and to the community cemetery where lost loved ones are remembered.

Imagine millions of monarchs flying across the finish line as they complete their long migration. Congratulations, monarchs!

Now that the monarchs have reached their winter home, we're about to wrap up our migration-tracking season. We'll be back next week with our final update of the season. Meanwhile, if you're still seeing monarchs, please report your observations. We'll continue to collect sightings until the monarchs have vacated the north!

A big alter (ofrenda) was placed at the main entrance of the church downtown to honor the memory of those who died in February.

The Monarchs Are Here!

Map of monarch butterfly sanctuary region.

Mexico's Monarch Butterfly Overwintering Region

Slideshow: Why is this place so special for monarchs?

Hundreds of millions of monarchs are migrating to Mexico to spend the winter—together—in an astonishingly small region. The butterflies will gather on a dozen mountaintops in a region that's only 73 miles wide.

What conditions make the habitat in this region ideal for monarch survival? In this week's slideshow, find out what scientists are learning about the unique microclimate of the monarch overwintering region.



Slideshow: Why is this place so special for monarch butterflies?

Why is this place so special for monarchs? 

The Migration: Maps and Journal Page 
Map of All Monarch Butterfly Sightings: Fall 2010 Map of Monarch Butterfly Roosts: Fall 2010 Migration Journal Page

ALL Monarch


Fall Roosts


For Your Journal
This Week's Questions

Seeing Monarchs? Please let us know!

  • Report frequently—at least once a week—as long as monarchs are present.
  • Count monarchs: Tell us how many monarchs you see per hour (or minute).
  • To report your sightings, press here.
The FINAL Monarch Migration Update will be posted on November 11, 2010.