to Challenge Question #11
do you think ALL the Western whooping cranes, including subadults, make
the risky migration north to Canada every summer?
Tom Stehn wondered why non-breeding cranes don't just stay Aransas for
years until they get mates and are ready to breed. Students who responded
did some great thinking about a tough question!
Tom adds his
thoughts, showing us all that scientists still wonder about many things.
For good reasons, some "answers" may always remain uncertain.
Seventh graders from Iselin Middle School point out
that the trip is a natural part of the whooping crane's life cycle.
Others mention the importance of migration for finding foods for themselves
and their young. Several of you think that cranes head north to escape
the heat. (Read
their full responses.)
(home schooler, Mt. Airy, MD) thinks that young whooping cranes "want
to get to know the migration route" when they are not "in
a hurry to get to nesting grounds and raise youngsters." He adds
this: "Maybe they need to observe the process of bonding with a
mate, making a nest, incubating the eggs, and raising young safely in
order to learn some things that may not be known already by instinct."
(Read his full
What Tom Stehn Thinks:
really have an answer that I feel confident with. My answer would have
two parts, but both may only be partially correct.
may not be very safe for whooping cranes to summer at Aransas
when they are molting and going through a flightless
period. There are
fewer predators on the nesting grounds in Canada
compared to Aransas. Also, what would a whooping crane do at Aransas
if a summer
hurricane hit the Texas coast? (No hurricanes
happen in Canada.) Perhaps facing the dangers
a year might be the lesser of two evils compared to staying at
- I think
the main reason that whooping cranes migrate every year is that “Mother
Nature” has programmed the birds to migrate to take advantage
of the tremendously productive northern breeding grounds
and yet escape the harsh winter conditions. Most biologists believe
that programming occurs through the process of evolution.
very strong programming instructions to give them the urge to migrate
such long distances twice a year. Maybe it would be just too difficult
a programming job to instruct whooping cranes to stay at Aransas
for several years and then start annual migrations.
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