Migration Day 20
Temps and Headwinds Prevent Progress
65 degrees F. in LaSalle County, IL this morning. Winds from the
south are blowing at 15 mph. For the fifth day in
a row, the weather is against the migration taking off from this
temps are best for migration. Joe Duff explains:
"Cooler air is more dense than warmer air. Warm air can actually
hold more moisture because there's more room for moisture. When air
is dense and compact (when it's cold) it's thicker, so when you breathe
in you get more oxygen. When you do a wingbeat there's more to push
against. When the propeller spins there's more thrust. When the wing
flies there's more lift to it. The aircraft works better, the engine
works better, the propeller works better, the wing works better. And
for the birds, their wings work better; they get more oxygen and it's
easier to cool their bodies. They don't overheat.
"It's just a lot easier to fly in cold air. That's really a big
factor in their endurance. Warm air just wears
them out very quickly. You see them panting quickly. Their tongues
come out. They start to splay their feet to help cool their bodies,
and they just can't fly."
This! Journaling Questions
in your journal why cooler temps make better migration conditions
for both birds and ultralights.
at the migration route map. Through how many states will the
Whooping cranes pass? How many of these states have you been in?
Look at a detailed map of these states and see if you can guess
cities and landforms the cranes will see from above. Why do
think they migrate south into Illinois and then east across
to Indiana, rather than taking a straighter, shorter line to Indiana?
What is the biggest city in any of these states? How might
over a huge city be a problem?)
Journey North is pleased to feature this educational
adventure made possible by the
Whooping Crane Eastern Partnership (WCEP).
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