Monarch Migration Update: September 6, 2012
Please Report
Your Sightings!
Report Your Sightings
Widespread drought on the migration trail raises concerns about this fall's migration. As monarchs travel through your hometown, what will you see? Discover when, where, and how to watch fall migration. Your observations reveal this year's unfolding story.

This Week's Update Includes:

Image of the Week
Nectaring in Colorado
Finding Nectar
Image: Charlene Ryan
News: Migration Slow, Numbers Low
A Slow Start
Every August, people in the north begin to report roosting monarchs. The butterflies cluster in trees to spend the night. According to reports through September 3rd, the roosts have been later to form, fewer in number, and significantly smaller in size.

  • The map shows the extent of the drought in the United States. As the monarchs travel through this region nectar will be in short supply.
  • The graph compares the number and size of roosts reported this fall and last fall, which was also a small population.

How to Watch
Print this flier so you know how to watch for migrating monarchs this fall, and what to report. It can be tricky to tell if a monarch is migrating or not. Here are some of the signs people are seeing:

People are thrilled when they see monarchs flying toward Mexico. "Directional flight" means the butterflies are flying in clear direction rather than fluttering about randomly. Peter Ashcroft of Fort Qu'Appelle, Sasketchewan watched 5 monarchs pass in one hour:

"The butterflies were all flying in a southeast direction with a moderate tail wind from the northwest."

Monarchs feed hungrily in the fall. They must have nectar to fuel their migration. They must also eat enough nectar to gain the fat they'll need to survive the winter in Mexico. One valuable way to monitor migration is to take a daily count in a butterfly garden. An observer in Minnesota counts every day around noon.

"Fourteen monarchs feeding today--FANTASTIC!! We were getting worried since the counts started out late and were low. Hopefully in the next week we'll start seeing the big migration and numbers will get close to last year."

This season's first fall roost wasn't reported until August 23rd, a week later than the typical first roost, and the roost was very small:

"Only about 10 monarchs tonight in the usual shelter belt where they have come for the last several years," wrote Connie Johnson from Watertown, South Dakota. On September 3rd, 80-100 monarchs arrived, "Largest group I have seen this year!"

In many southern states, people rarely see monarchs during June and July. Monarchs re-appear in August. Presumably, the butterflies are early migrants moving down from the north and they are reproductive. From Charleston, South Carolina, Porter-Gaud School reported on Wednesday:

"Ms Veron's class and Mrs. McCabe's class observed one female monarch laying eggs in our butterfly garden."

How long will monarchs continue to lay eggs where you live? Please watch carefully and report your observations to the egg and larva map!

US Drought
Drought Map
Roost Analysis
A Slow Start
How to Watch Fall Migration
How to Watch
Nectaring in New York

Nectaring in New York
Image: Gale VerHague

Monarch butterflies clustering at roost site in Oshawa Ontario
Roosting in Canada
Image: Jim Ellis


Monarch butterfly caterpillars, chrysalis and adult

Image: Sheila Turner

Slideshow: When, Where and How to Watch Fall Migration
What kind of observations does Journey North collect in the fall and how are they important?

Slideshow: When, Where and How to Watch Fall Migration

  • Data Hunt Challenge: students read and analyze sample observation reports.
  • Ask the Observer: students add details to "missing information" reports.
  • My Practice Report: students submit sample sightings reports to live map.



The Migration: Maps and Journal Page
Let's find out when and where monarchs appear this fall. Please watch for monarchs that are flying in "directional flight," resting at overnight roosts, or refueling at flowers in fields, gardens, or roadsides.
Monarch Butterfly Migration Map: All Sightings, Fall 2012 Monarch Butterfly Migration Map: Fall Roosts, Fall 2012 Journal Page
All Sightings
(map | animation | sightings)
Fall Roosts
(map | animation | sightings)
The next migration update will be posted on September 13, 2012.