Update from the Whooping Cranes' Winter Headquarters
Aransas National Wildlife Refuge
Austwell, Texas
February 29, 2000
Dear Students,
This year has been a struggle for the whooping cranes, with difficult habitat
conditions both summer and winter. However, the flock has managed to INCREASE their
numbers by TWO to reach 185, a record number. Here is a brief chronology of their
year:
SUMMER 1999, WOOD BUFFALO NATIONAL PARK: When the whooping cranes reached the nesting
grounds in Wood Buffalo National Park in the Northwest Territories of Canada, below-average
snows during the winter had left the marsh with low water levels. Much-needed rainfall
came the first week in June, but unfortunately right when the eggs were hatching.
Some of the very small chicks did not survive in the wet, cold weather. Forty-eight
nesting pairs did produce 48 chicks, including 10 pairs with twin young. However,
none of the sets of twin young survived, and only 20 chicks were still alive in mid-August
as they began flying lessons at about 10 weeks of age. Seventeen of these survived
the hazards of the long, 2,500-mile migration and made it to Aransas by the end of
the year. This compares with 18 chicks that reached Aransas last year.
FALL MIGRATION, 1999, CANADA TO TEXAS: The fall migration started early, with two
cranes sighted in Saskatchewan on August 31. Most of the whoopers crossed the U.S.
starting in mid October. The most notable aspect of the migration was that 44 different
whooping cranes stopped at Quivira National Wildlife Refuge in Kansas at different
times throughout the fall. Eighteen whoopers were present the day the refuge duck
hunting season was scheduled to open, but the refuge manager postponed the hunt until
the birds had safely departed to continue their migration. This spot has become a
major stopover for small groups of whoopers in the fall. Weather during the fall
migration was unseasonably mild, but the migration seemed to progress at about or
slightly slower than the normal pace. The first date recorded for confirmed observations
of migrating whooping cranes was September 16 in the U.S. As of mid-October, the
only confirmed whooping crane sightings were from Saskatchewan and North Dakota.
Starting the week of October 20, sightings became numerous cross the U.S. Whoopers
were definitely on the move, including 20 birds at Quivira NWR, Kansas on October
23, and 14 whoopers at Salt Plains NWR, Oklahoma on October 26. After a major front
reached the Texas coast on November 2, high pressure throughout the central US delayed
the whooping crane migration. Sightings were reported from Alberta (1), Saskatchewan
(32), North Dakota (14), Nebraska (5), Kansas (19), Oklahoma (8), and Texas (4)
(Jobman, 2000 Cooperative Whooping Crane Tracking Report). The latest recorded observation
was December 29 in Barton County, Kansas, unusual for a whooper to still be that
far north.
FALL ARRIVALS AT ARANSAS, 1999: The average arrival date for the first whooping cranes
at Aransas is October 16. In 1999, the first whoopers rode in behind a strong cold
front that reached the Texas coast the afternoon of October 17. They were first observed
October 20 on a census flight with 8 adults and 1 juvenile present. Excellent migration
conditions were present at Aransas with northwest winds October 30 through November
3. An estimated 93 cranes arrived at Aransas between the end of October and middle
of November. Cranes totalled 119 on November 17 and 182 on December 4. About 84%
(156 whoopers) of the arrivals occurred between October 27 and December 4 (Jobman
2000).
1999-2000 WINTER, ARANSAS: Things have been very chaotic for both myself and the
whooping cranes at Aransas this winter. The pilot I had been flying with every week
to count the birds had to have emergency heart bypass surgery. Fortunately, he is
well on his way to a full recovery. I frantically arranged for U.S. Fish and Wildlife
Service pilots from Louisiana and New Mexico to help me with the census flights until
I could find another pilot. Fortunately, by the first week in January, a pilot from
Victoria, Texas had met all the aircraft inspections and extra check rides required
for these low level flights conducted 200 feet above the ground, so I was back in
the crane counting business every week. By this time, the whooping cranes had eaten
many of the blue crabs in the marsh. This favorite food of the whooping cranes is
very high in protein, but it had become scarce. Also, the waters were very salty
due to a drought, so the birds were flying inland several times a day to find fresh
water to drink. The refuge staff conducted prescribed burns of the oak brushlands
to provide additional food for the cranes. The whoopers love the roasted acorns that
they can find on the ground after the tall prairie grass is burned off. Cranes left
their traditional marsh territories and formed large flocks on the burns. One day
I counted 38 cranes all together on one burn. It is incredibly unusual for that many
whooping cranes to get together, since mated pairs usually remain in their salt marsh
territories and keep all other whooping cranes out of that area. My census flights
indicated that at least 185 cranes were present in the flock. This is a record number,
two more than last winter. This includes one whooping crane that never made it to
Aransas. This crane is wintering in West Texas with sandhill cranes. Because of all
the crane movements to burns and freshwater, it has been very hard to get an accurate
count. There could be as many as 191 cranes present. I'll keep trying every week
to figure this out. And I'll continue to worry about the shortage of blue crabs for
the whooping cranes to eat.
SPRING MIGRATION, 2000: The first whooping cranes normally start the migration about
mid-March, but a few could leave a little before that. Most of them will leave by
mid-April. I'll be flying in a small airplane once a week all spring to record the
number of whooping cranes that start the migration each week, and I'll let you know
how the count is going. Despite warm spring weather here, the whoopers "know"
it is too early to start their journey since it is still frozen up north.
Regards,
Tom Stehn
Whooping Crane Coordinator
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