March is a critical time for the whooping cranes at Aransas. Food supplies
for them were limited in January and February when tides were extremely
low, draining the marshes. Their favorite food, the blue crabs, had moved
out into the bays to deeper water. That meant the crabs were not available
to the cranes. Tides are now higher. I hope crabs have moved back into
the crane “refrigerators” (meaning the salt marshes where
cranes spend the winter). The whooping cranes need a steady diet of crabs
to build up fat reserves as they gain weight just before the spring migration.
These fat reserves are used during the migration and also help them get
through the nesting season. Fat reserves help then because the males
and females take turns sitting on the eggs and don't have as much
time to find food.
Bad News and a Discouraging Year
I found more bad news on my last census flight (March 1st).
Another juvenile has died. This juvenile's father had died earlier this
winter at the age of 28 years. For a crane, this is approaching old age.
(I wish I were still 28! I'm double that age.)
The juvenile had stayed with its mother after its father died. But for
several weeks we sometimes saw it alone, a sign that perhaps it wasn't
speculate that perhaps the juvenile had gotten a fatal disease, such
as avian tuberculosis.
of this bird leaves 215 whooping cranes in the flock, the exact same
number that were present last spring. It
has definitely been a "break even" year for whooping cranes—a
very disappointing turn of events considering the excellent nesting
season they had last summer with 30 juveniles making it to Aransas
Twenty-six of the older birds died last year. This is way too many.
A total of 5 whooping cranes (1 adult and 4 juveniles) have died this
This has been a discouraging year.
All Cranes Still Present
My March 8 census flight had to be cancelled due to winds gusting up
to 45 miles per hour (tropical force strength and very unsafe for flying).
Although there have been two reports of whooping crane groups in migration,
my best guess is that all the whooping cranes are still at Aransas.
Every year, people get anxious and think the whooping cranes are going
to leave "early," and
often we get false sighting reports. But the whooping cranes "know" that
it is still too early to head for Canada and they would encounter snow
and frozen conditions if they left now.
The Rewards of Good Timing: A Question for You
The correct timing for most of the breeding whooping cranes to leave
Aransas starts the last week in March and continues through April 20.
you when I said the whooping cranes "know" not to
leave too soon. How is it determined when they should leave? Think
about what bad things could happen if they leave too early, or what would
to them on the nesting grounds if they got there too late. Nature has
a system of "rewarding" the birds that leave at just the
right time, and in that way the timing of the migration has evolved.
Your Question: What reward
do the whooping cranes get?
Whooping Crane Coordinator
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