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Describe
the patterns you notice.
- What's
happening in the far north?
- What
direction do the colored clusters seem to be moving?
- Do
you notice a brand new light blue dot on this map in southern
Texas? How would you explain that?
- Why
do you think there are fewer reported sightings in May? (Think
about the time of year in a robin's life cycle. Also thinking
about people like you who send in many of our sightings.)
Look
at the clusters of color.
Find
the latitude at which half the medium blue dots are above and half
are below your string. Do this for the other colors, too.
- Does
the latitude change during each data period?
- Is
the change steady?
- What
does this tell you about the general (average) progression of
the migration?
Making Connections:
What Do We Learn From Analyzing Robin Maps?
- Make
a list of the things you learned as you looked at robin migration
patterns. (What do you know and what can you infer?)
- How
can you find out where the center of the migration is for any
given week?
- How
do most robins in North America seem to move in late winter and
spring? What exceptions did you notice?
- Why
do you think robins follow the migration patterns they do?
Ask
your own questions about robin maps!
See this page of journaling questions: Making
Sense of Journey North Maps
What
Scientists Have Learned
- Using
data like these, scientists have discovered that as temperatures
rise and days grow longer, American robins sense the changes.
- Some
individual robins are more sensitive than others, so some
begin singing and showing migratory behaviors when temps
are still below freezing.
- Some
robins are less sensitive than others, and wait to migrate
until temperatures are very warm.
- By
comparing robin movements from data like these with day-by-day
weather data, scientists have learned this: Although there
are many confusing exceptions, the majority of robins move
when the average temperature is about 36 degrees F. (See
the activity, Spring
Fever.)
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