Monarch Butterfly Migration Update: September 23, 2005
Today’s Update Includes
Highlights From the Migration Trail
Dr. Lincoln Brower has studied monarch butterflies for over 50 years. From his mountaintop home in Virginia he sent the official word on Sunday: “Today at 4:30 pm, 21 fresh monarchs arrived in our front garden and are nectaring on the asters we have planted. This is almost certainly the first wave of monarchs of the fall migration.”
Third graders at Swain School in Allentown, PA, have been studying monarchs all fall. After their snack break on Tuesday they saw two migrating monarchs and “the hallways were echoing their excitement,” said teacher, Karen Green. For weeks, the kids had been asking her how they could get a "circle" posted on the Journey North migration map. Take a look at the map today. Can you find Allentown, PA?
Here are a just few of the many other places children saw migrating monarchs this week. Can you find these towns on the map?
Who Saw the Most Monarchs This Week? Migration-rate Math
Follow the link below to a few of this week's observations. Read the comments and calculate the migration rate for each. Add your favorites to your own Migration Highlights Map!
Refueling at a Butterfly Garden Surrounded by Crops
Fly across the landscape and measure how many miles this patchwork pattern of cropland extends. Farming practices have a wide-scale impact on monarch habitat, and a butterfly garden can be an important place for a monarch to refuel.
How Much Fuel do Monarchs Burn? The Energy Costs of Flight
So true! A monarch’s fuel is fat (technically, “lipids”). Because the monarch is so small we measure its fuel in milligrams (mg). A monarch with a full tank can carry 140 mg of fuel. If it rides with the wind--without flapping--it can travel 1,060 hours on that single tank of fuel. However, when a monarch flaps it burns its fuel very quickly. When it flies as fast as it can (in what’s called “escape flight”), a monarch flaps its wings up to 12 times every second! A monarch burns 12.7 mg of fuel every hour during escape flight. Do the math in Challenge Question #4 and you’ll see why the wind is so important to migrating monarchs:
Discussion of Challenge Question #2: How Many Butterflies in a Piece of Paper?
It's hard for us to imagine the importance of wind in the daily life of a butterfly. Challenge Question #2 asked, "If the average monarch butterfly weighs 500mg, how many could you cut from one sheet of paper? Before you look at our answer, lift one piece of paper and feel its weight. Then guess how many butterflies would weigh the same:
Discussion of Challenge Question #1: Why Do Monarchs Form Roosts?
Mrs. Nunnally's second grade class at Peter Woodbury School in Bedford, NH thought of two important reasons:
Great job! Protection from the wind is also important. If you find a roost, notice that the butterflies gather on the side of the trees that's protected from the wind.
How to Report Your Observations
Put your monarch news on the map! Watch for monarchs flying, feeding, or resting. Tell us how many monarchs you see per hour (or per minute). Note the temperature, wind speed and direction. When you're ready to report see:
The Next Monarch Migration Update Will Be Posted on September 30, 2005.
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