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Monarch Butterfly Migration Update: September 2, 2005

Today’s Update Includes

Latest Migration Maps
Click for live maps--then read what each observer saw!
Migration Sightings
Sightings of Overnight Roosts PEAK
Migration Sightings

Highlights From the Migration Trail
A year ago at this time, most everyone was talking about how few monarch butterflies there were. At best, only a handful of monarchs were being seen at nectar sites or flying overhead, and not a single large roost had been reported. What a welcome change this year! Already, southbound butterflies have been seen at points across the map and people in the north have found 27 large roosts. This year, everybody seems to be talking about how many monarch butterflies there are. During the last week for example:

  • Thousands of monarchs in our fields today. Largest numbers at my location in many years!
  • More monarchs in my yard tonight than I had for the whole season last year.
  • We're seeing monarchs again after several years of no sightings.

Comments like these are signs that monarchs have rebounded during the summer breeding season. Yet how many monarchs there actually are, and what causes their numbers to rise and fall, are questions that baffle scientists.

Monarchs resting in Watertown, South Dakota
...1,835 miles from to their winter home in Mexico
Photos Courtesy of Connie Johnson   
  The monarchs were discovered in this row of trees called a "shelterbelt." Trees are planted in South Dakota this way to protect against the strong prairie winds.

Why Do Monarchs Form Roosts? Clues from the Field
Migrating monarchs rest at overnight roosts at the end of the day. Imagine finding a roost in your hometown, with hundreds or thousands of butterflies! How might roosting help monarchs survive the migration? Read this week's collection of observations and look for clues. Then answer Challenge Question #1:

Estimating the Number of Monarchs in a Roost: Let's Practice
People are dazzled by the beauty of fall "butterfly trees." It's rare to see more monarch butterflies than a person can count. Maybe this is why people always try to count them!
If you were to discover a monarch roost, how would you count the butterflies? Scientists often use photographs to estimate numbers, whether they are counting whales or caribou, bats or butterflies. How many monarchs are in the roosts in these pictures?
Why Do Nightly Monarch Counts Go Up and Down?
At any overnight roost, the number of visiting monarchs tends to rise and fall from one night to the next. Monarchs roost every year in Mr. Paul Viger’s yard in Campbell, Minnesota. What do their resting patterns tell us about monarch migration patterns? Take a look at Mr. Viger's data and see what you can find:

Fly Like a Butterfly All the Way to Mexico
Try Google's new interactive satellite maps and you'll feel like you're flying! Follow the step-by-step instructions at the link above. We'll show you how to find the monarch's winter home in Mexico and your own hometown. Then zoom-out and fly like a butterfly all the way to Mexico!

Ultralight Plane Traveling with the Migration
Painted like a monarch, an ultralight plane is flying along the migration trail this fall with the monarchs. The crew began the journey in Quebec, Canada and is about to cross the U.S. border, over Niagra Falls, into New York state. The pilots are sharing the view as they look down on the earth below. You can see pictures and read tales about their journey.

Habitat and Survival: What do Monarchs Need During Fall Migration?
Monarchs must find habitat all along their route to Mexico. As you travel with the monarchs, find examples of their habitat needs. Look for specific ways they find food, water, shelter, and space. Record the many challenges to survival they face this fall, and in the full year ahead.

The place and conditions where all of an organism’s needs for life are met. Food, water, shelter and space are key components of an organism’s habitat.

Report Your SightingsHow to Report Your Observations
Put your monarch news on the map! Please send reports of monarchs feeding, flying, and resting.

The Next Monarch Migration Update Will Be Posted on September 9, 2005.


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