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April 19, 2006
Dear Journey
North,
We’re approaching the end of departures of the whooping cranes
from Aransas! On a census flight today, I could only find 12 cranes.
This is a drop from 35 found a week ago. Thus, 94.6% of the crane flock
has migrated. The last 2 remaining
family groups were among the 23 that started migration this past week.
Whoopers Right on Schedule
The
big push-off of cranes heading north has occurred right on schedule.
And why not? The weather in Texas has been windy and warm all week,
perfect
conditions to help the cranes migrate. Temperatures have been in
the upper 80’s
along the coast. About 30 miles inland, when you get away from the
effects of the breeze crossing the cooler Gulf waters, temperatures
have already
reached 104 degrees. Imagine what summer in South Texas is like! However,
the cranes may currently be facing very different conditions as they
cross the U.S. The weather channel talked about 2 feet of snow that
fell in South Dakota overnight. I remember when I followed radioed
cranes during the
spring migration 20 years ago; I first encountered snow banks along
the road in the Dakotas. I stopped to take a photograph. The snow was
quite
a surprise for someone that lives at Aransas, where it rarely
snows. What difficulties
would snow storms cause for the cranes during migration?
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Subadults
and Adults: Different Migration Schedules
The 12 whooping cranes
still at Aransas are all what I call “subadults.” Although
they look identical to adult whooping cranes, subadults are 1-4 years
of age and too young to breed. These subadults aren’t
in any hurry to depart. After all, they aren’t going
to build nests and raise young this summer.
In contrast, all the adult pairs have migrated. This occurs every year by April 20th. The adult pairs need to get going. They must make a rapid 2-3 week migration to reach Canada, build a nest, lay their eggs, and raise their young. The chicks have a lot of growing to do before fall, when the family will migrate together to Texas.
What
About the Lone Juvenile, Left by Its Parents?
The juvenile whooping crane that last week
had stayed behind when its parents migrated apparently got in the
right frame of mind
and headed north, possibly by itself. This juvenile should
be fine. Even though it has only migrated one time last fall between
the nesting grounds and Aransas, it will have no trouble migrating
back north to the
exact same marsh ponds where it grew up. Now that is
quite a talent. Do you have as great a talent as that? Sure
you do! Reading, writing, thinking and making friends laugh
are pretty miraculous talents when you take the time to appreciate
them!
Tom Stehn
Whooping Crane Coordinator
USFWS
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North. All Rights Reserved.
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