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Fall
Migration: Too Cold to Fly Today?
Monarch butterflies
are in a race against time during fall migration. They must vacate the north
before they're trapped by the cold. In order to fly, a monarch's muscles
must be warm enough. In fact, if a monarch's thoracic (body) temperature
is below 55 F (13 C) it can't fly at all.
| Watch
how temperatures fall in the fall! |
| This
map shows how quickly temperatures drop as the fall season progresses.
The days are getting colder (and shorter, too)!
With
each passing day, monarchs have a smaller and smaller window of
time in which they can fly. |
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| Try
This! Can a Monarch Fly Today? |
Migrating
monarchs don't fly at night. They can only continue their journey
south when their temperature is above 55 degrees F.
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Predict:
Will monarchs be able to fly today in your hometown? What time
in the morning will they be able to lift off? What time in the
everning must they come down to rest? How many hours do you
predict monarchs could fly between sunrise and sunset today?
(See: sunrise/sunset
look-up.)
- Measure
the outside temperature every hour during the school
day. Is it above or below 55 degrees F? If it goes above 55 F,
for how many hours does it stay there?
- Think!
Between sunrise and sunset, how many hours could monarchs have
flown? During how many hours was it too cold for them to fly?
How did this compare with your predictions?
Extensions
- Continue
gathering data
as the season continues. Each day, check the previous day's temperatures.
Go to weather.com.
Put in your zip code. Choose "yesterday" from the menu
and then choose "hourly reports." (You'll find times
and temperatures in the lefthand columns.) Make a graph that shows
how many hours in each 24-hour day the temperature is above (or
below) 55 F.
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Predict where
in the country monarchs will be able to fly today or
this week. Use this interactive
map.
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| Wait
. . . There's more to it! |
Monarchs can raise their temperatures above
air temperature by 1) basking in the sun and 2) shivering. Explore
more!
- Basking
Behavior: >>
- Shivering
Behavior >>
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National
Science Education Standards
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