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Analyzing
the Whooping Crane Population Data
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Click
graph to enlarge
(numbers updated each January)
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How is
the world's last remaining natural migratory flock of Whooping cranes
doing? The population figures in the table below show the growth
of this flock: the Western
flock, which migrates between Canada (nesting grounds) and Texas
(wintering grounds). Until 2001, these birds were the world's entire natural
flock of wild migratory Whooping Cranes. In that year, experts began
to reintroduce
an Eastern flock. This new second flock migrates between Wisconsin
(nesting grounds) and Florida (wintering grounds).
Activity:
Make Three Graphs
Show changes in the population
levels for the only natural migratory flock (the Aransas/Wood
Buffalo flock, or Western flock) of this endangered species. Use the
population data below to
make
3 graphs:
- The number of
Whooping Cranes per year.
- The increase
in the number of Whooping Cranes per year.
- The percent increase
in the number of Whooping Cranes per year.
Population
of Whooping Crane Natural Flock (Aransas/Wood Buffalo Flock)
1940-Present* (December Counts)
| Year |
#
Cranes |
Year |
#
Cranes |
| 1940 |
22
|
1997 |
182 |
| 1950 |
34
|
1998 |
183 |
| 1960 |
33
|
1999 |
185 |
| 1970 |
56
|
2000 |
177 |
| 1980 |
76
|
2001 |
174 |
| 1990 |
146
|
2002 |
185 |
| 1991 |
132
|
2003 |
194 |
| 1992 |
136
|
2004 |
216
|
| 1993 |
143
|
2005 |
218
|
| 1994 |
133 |
2006 |
237 |
| 1995 |
158 |
2007 |
266 |
| 1996 |
160 |
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Deaths
may occur at any time, so counts
can change.
Try
This! Discussion or Journaling Questions
- After
making your 3 graphs, describe the different visual picture each
graph gives
you. Was it helpful to graph the data in these different ways?
- Think
about what each graph means. What different information does each
graph show
you? Give each graph a title.
- Which graph do
you think is the most revealing?
- Are there times
when the numbers appeared to increase significantly, but the percentage
increase was not as pronounced?
- What
questions did the graphs make you think of about the climb in
population size?
- What
reasons do you suppose are behind these population changes? List
all the factors you can think of that might have caused the population
to rise (or
fall) as the data show.
- During
which decade did the population increase at the fastest rate?
Which year did it increase the most?
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