Monarch Migration Update: Sept. 2, 2010
Please Report
Your Sightings!

"In the evening just before sundown, hundreds of monarchs were spotted flying between tree tops before settling down for the night." Monarchs rest during migration at overnight roosts, and people are delighted to discover them. Mapping the locations of these roosts can reveal the monarch's main migration pathways to Mexico. This week, find out what we know about this intriguing migration behavior, and the important role citizen scientists play in gathering information.

This Week's Update Includes:

Image of the Week
The Fall Roost: What makes them so hard to study?Image: Peter Rasberry

The Overnight Roost
Why so hard to study?

News: People Reporting Monarchs from Canada to Mexico

Maps help us visualize data. We can see things we might not otherwise notice. Take a look!

The Map of All Monarch Sightings
The purpose of the map of all monarch sightings is to show monarch distribution. During the month of August, 641 people reported monarch sightings from three countries. Their sightings help answer this question: Where were monarchs present in August 2010? According to the data reported, monarchs were present in ___ Canadian provinces, ___ U.S. states, and even ___ Mexican states. How do you think this map will change in September?

See any surprises?
Most surprising was the presence of monarchs in Mexico in August. Nobody knows whether those monarchs were early migrants from the north or monarchs that had been breeding locally. What do you think?

The Map of Overnight Roosts
The map of overnight roosts reveals information about the distribution and abundance of migrating monarchs. Roosts are places with large numbers of monarchs, so they show us where migrating monarchs are abundant. In the weeks ahead, the roost map will reveal the main migration pathway to Mexico. What does the map show right now? According to the data reported:

  • Where are migrating monarchs most abundant?
  • What geographic features seem to be funneling the migration? Here's a clue (spelled backwards): Eht Taerg Sekal
  • What other factors could help explain why reports of monarch roosts are concentrated where they are? Clue: Eht noitacol fo elpoep.
Did you know?
Our migration maps only show where observers saw and reported monarchs. They do not necessarily show the actual distribution or abundance of monarchs. Can you explain the difference?

Monarch butterfly laying eggs in Kentucky: August 2010

Students spot monarch laying eggs in their Kentucky garden.

The Migration: Maps and Journal Page 

Seeing Monarchs? Please let us know!

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 Map Questions
Slideshow: Why do monarchs form roosts during fall migration?

Scientists have many questions about how and why monarchs form roosts during fall migration. In this slideshow, follow the questions to find out what is known about roosting monarchs, consider possible explanations, and pose your own questions.


Research Question: The best monarch books for kids?

Which titles belong on your list of the best monarch butterfly books for kids? We've assembled our list of titles we call "too good to miss." Research, read, write, and share your opinion using the book review template.

Monarch Butterflies: Book List
Book List

Book review template

Book Review Template

The Next Monarch Migration Update Will Be Posted on September 9, 2010.