Butterfly Migration Update: February 27, 2004
Field Notes from Mexico by Dr. Bill Calvert
Dr. Calvert phoned home from Mexico on Wednesday after visiting the Sierra Chincua sanctuary. The season is progressing right on schedule. "The most intense part of the dry season is beginning now," he said. "The forest is literally drying out. And the butterflies no longer can take water from dew patches, or wet areas in the forest, because they’re drying up."
Writing Prompts for Your Science Journal
Seasons in the Tropics: Wet and Dry
Below the Tropic of Cancer--and all the way to the Tropic of Capricorn (23.5 S)--is the region known as the "tropics." In the tropics, temperatures and photoperiod don't vary much year round. However, precipitation does vary greatly.
There are distinct dry and rainy seasons in the tropics. The cycle of the seasons in the sanctuary region of Mexico follows this pattern:
Scientists Learn from Butterflies: More Land is Needed
When land was put aside to protect the monarchs in 1986, the biological needs of the over-wintering butterflies were not well understood. It took many years of study to realize that, during the dry season, the monarchs move to lower elevations where there is water. Over time, scientists realized that the monarchs were moving beyond the sanctuary boundaries. The land the butterflies needed during the dry season was not protected for them.
Tropical vs. Temperate Zones: Watch the Seasons Change
Watch how the seasons change in different parts of the globe. Try this simple activity once a month from March to June. Predict the temperature and day length at your temperate zone home and at the monarch’s tropical winter refuge. Then check your predictions against the actual data.
Life in the Sanctuary Area: Water Resources for Families
How does life change for people during the rainy and dry seasons? Maria Luisa and her family share their story.
Imagine carrying 800 liters of water every day to your house from a well a half a mile away...by foot!" begins Maria Luisa.
Discussion of Challenge Question #4
Bough-full of Butterflies
"If the typical monarch weighs 500 mg in midwinter, how much would a branch loaded with 15,000 butterflies weigh?," we asked.
What else did they find that weighs the same? Two newborn babies, or 128 Star War Action figures, or 4 ibooks, or 3 bags of flour or a partly filled box of computer paper, say the students! Here's their math.
How Many Paper Clips Bend a Branch? Just Ask Nikki!
Thursday at recess Mrs. McGehee's students tried the paper clip test suggested in the Feb. 20 update. They have been studying measurement in class and knew that a paper clip weighed approximately 1 gram. They estimated that the branch would bend at between 250 - 500 paper clips.
Great job! So, if the typical monarch weighs 500 mg, how many monarchs could bend the same branch?
Reasons Monarchs Move
“Monarchs move during wintering because they need to survive,” said Mallika of Harrington School in Lexington, MA. “They might move because of hail, rain, predators, climate changes, and more. Also because they need a certain amount of warmth and moisture,” she added.
Emerging on the Migration Trail!
Report the FIRST MILKWEED LEAVES to Emerge This Spring!
Please Report Winter Monarch Sightings NOW
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