Monarch Migration Update: Sept. 22, 2011
Please Report
Your Sightings!

The first day of fall is approaching, temperatures are falling, and monarchs are flying. This week, explore the world of monarch tagging. Tiny tags lead to big discoveries!

This Week's Update Includes:


Image of the Week

Monarch Butterfly with proboscis labeled.
Image Jim Gilbert

Making History

News: On the Move!

Central Flyway
Cool temperatures descended across the Central Plains this week, and along came the highest migration counts of the season:

9/20/11 Ottawa, Kansas
"I had to tell SOMEONE," wrote a Kansas man who works in a wholesale nursery. "We have about 2,500 Butterfly Bush plants. The past few days I've noticed an influx of Monarchs—but today there were hundreds (400? 500? 600?) nectaring on the plants."

9/20/11 Stillwater, OK
"Between noon and 12:05 today, I counted 38 monarchs nectaring and flying in our small backyard. Why so many this year? Perhaps because much of the surrounding prairie in KS, MO, and OK is in drought, and probably has little blooming."

The first two roosts were reported in Texas this week. Also reported was what a Texan calls a "small to medium" flight: 100 monarchs in one hour!

Eastern Flyway
Enthusiasm was high in the eastern flyway, when a clear pulse of monarchs finally appeared this week. From Vermont to Virgina, monarchs were moving:

"Knowing I could report it, my daughter sent me a text, advising of a Monarch butterfly sighting in Essex Junction, VT."

"The magic returns! An hour and half before sunset I spotted about 200 monarchs roosting in the evergreen trees along the roadway," wrote a woman from Long Island, NY.

"They are flying by my front porch at about 100 a day. Every one has been on the same track!" came the word from Pennsylvania.

"We sat outside our school building and watched butterflies migrate south," wrote Highland High students from Virginia on Wednesday.

"The migration has arrived!" Dr. Brower proclaimed from his home in central Virginia on Monday. "Amazing that they suddenly appear." Dr. Brower caught 32 monarchs in 20 minutes as they nectared in his garden.


Graph: Number of roosts reported as of September 14th each year

Nectaring at the Nursery

Monarch Butterflies at roost site in Mexico.
Basking Butterflies

Graph: Number of roosts reported as of September 14th each year

Roosting on Long Island

Seeing Monarchs?
Report Regularly!

Tell us when and where monarchs are present.

Please report at least once a week.

Slideshow: Tagging Monarchs | Tiny Tags, Big Discoveries

Every fall people all over North America carefully catch monarch butterflies, and place a tiny, paper ID tag on one wing. The tagged butterflies are released and continue their journeys. It is always exciting to find a tagged butterfly and wonder when and where it was tagged. Use this slideshow and its accompanying activities to explore the essential question: What can we learn about migration from tagged monarchs?


Tagging Monarchs: Tiny Tags, Big Discoveries


The Migration: Maps and Journal Page
Monarch Butterfly Migration Map: All Sightings, Fall 2011 Monarch Butterfly Migration Map: Fall Roosts, Fall 2011 Migration Questions: Week 2

All Sightings

(map | sightings)

Fall Roosts

(map | sightings | archives)

Seeing Monarchs? Please let us know!

The next Monarch Migration Update will be posted September 29, 2011.