A Look at Wind and Monarch Migration
The drive to migrate is strong. One September afternoon in Iowa, biologist Dr. Royce Bitzer watched how wind affects monarchs as they fly. Unless the monarchs stayed close to the ground, he noticed, the wind carried many in the wrong direction.
"The wind was blowing from the southeast at 13-18 mph. Yet quite a few monarchs were being forced westward if they got more than 6 to 8 feet above the ground. But the ones that stayed low were making their way south-southwest to southwest. It seemed that day as if there was a definite boundary layer near the ground within which the monarchs could make their way south, but if they rose above that level, they would end up struggling and getting blown off course," he observed.
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How Strong is the Wind Today? You can learn how to read the speed of the wind by watching its effects. How strong is the wind when leaves rustle, trees toss, or dust flies? |
Learn to Read the Beaufort scale! |
Journaling Question
It's hard for us to imagine the importance of wind in the daily life of a butterfly. We're so heavy. Only the most powerful winds on the planet could carry us away. A butterfly, however, weighs about as much as a scrap of paper its size. Consider this:
How Many Butterflies in a Piece of Paper? If the average monarch butterfly weighs 500 mg, how many could you cut from one sheet of paper? (Assume the paper measures 8.5 X 11 inches). Describe how you solved the problem as part of your answer.
Try the math yourself.
Then see how we solved the problem. >>
