Dear
Journey North,
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Juveniles still have some rusty brown feathers.
Photo:Diane
Loyd |
An
important and dangerous time in the life of a whooping crane
is when the juvenile (a bird
less than 1 year old), separates from its parents. This separation
usually occurs in late May, just before the parent cranes re-nest
in Canada. Biologists have even observed the adult cranes showing
their youngster a suitable marsh near their nesting territory and
dropping off their juvenile before they settle to defend their
nesting area.
Occasionally a juvenile will separate from its parents in Saskatchewan
during the spring migration. Sometimes this happens
before the family returns to Canada. Sometimes an adult pair will
start the spring migration from Aransas and the juvenile stays
behind. It can even occur sometimes during the fall migration.
For some unknown reason, “junior” gets left behind
as its parents continue the migration all the way to Texas. This
is a very dangerous period since the youngster no longer has its
experienced parents there to watch for and guard against predators. How
do whooping cranes stay safe from predators when they are sleeping
at night? How would a whooping crane be able to fight off something
as big as a coyote? How
do juveniles cope without their parents to help them? This week
I'll tell some real-life stories that help us explore these questions.
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The
Lone Nebraska Juvenile: A Happy Prediction >> |
Mohawk's
Story: Unknown Fate. >> |
Two
Unlucky Juveniles >> |
I
think something about the food shortages this winter are causing
the juveniles to separate from their parents. A photographer
noticed one juvenile whooping crane getting attacked by a neighboring
pair of cranes. The parents of the adult flew off and away from
the aggressive neighbors, but apparently the juvenile was too
weak
to fly. Although the juvenile was not injured in the attack,
it was no longer with its parents and too weak to fly. A predator
killed it that night. I
found the carcass. Tests indicated the juvenile was starving
and very thin, but the health experts could not tell me why or
isolate a disease that the crane may have had.
So
far this winter, 9 juvenile whooping cranes and 3 adults have
died at Aransas. I’ll try to find out on my next census
flight if any more of the whooping cranes are missing.
This is
a horrible winter for the cranes. But they are a long-lived
bird, and most of the flock will survive these tough times! (And
when you read Scarbaby's
Triumph, you'll know there's still good
news happening.)
Tom Stehn
Aransas National Wildlife Refuge
Austwell, Texas
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