The third aerial census of the 2008-09 crane season was conducted December
5, 2008 in a Cessna 210 piloted by Gary Ritchey of Air Transit Solutions of
Castroville, Texas with USFWS observers Tom Stehn and Carey Strobel.
Visibility was difficult for finding cranes due to heavy overcast skies
during the 8.0-hour flight.  Located were 198 adults + 31 juveniles = 229
total.
This was 37 fewer cranes than the previous flight conducted November 25th.

Recap of cranes (229) found at Aransas on the aerial.
|------------+---------------|
|            |Adults + young |
|------------+---------------|
| Refuge     |  54 + 11      |
|------------+---------------|
| Lamar      |    6 +   3    |
|------------+---------------|
| San Jose   |   43 +   4    |
|------------+---------------|
| Matagorda  |   79 + 11     |
|------------+---------------|
| Welder     |  16 +   2     |
| Flats      |               |
|------------+---------------|
| farm fields|        -      |
|------------+---------------|
| Total      |198 +  31 = 229|
|------------+---------------|


Explanation of numbers

Experience indicates that only 85-90% of the flock can usually be located
when skies are a thick overcast.  This was definitely the case on today’s
census.

Flock Estimate

For the second week in a row, only 2 family groups were located on Welder
Flats.  This makes me postulate that the 4 family groups seen at Welder
Flats on the November 14th flight may have cranes that had recently arrived
that later moved on to other parts of the crane range.  Thus, I cannot add
two family groups on to the estimated flock size as I had done after the
November 25th flight.  Therefore, the current estimated flock size is 230
adults + 40 juveniles = 270.  Those numbers are NOT firm and are lower than
my previous estimate of 275.  Future flights will focus on determining the
number of juveniles present and total flock size.

Migration Update

Migration sightings of a pair of cranes were as follows:
      11/24 - pair last seen at Cheyenne Bottoms, central Kansas
      11/28-11/29 - pair seen at Salt Plains in northern OK
      12/03 - pair seen 4 miles north of Aransas in the farm fields
Given the group size and timing, I am guessing these could very well be the
same pair tracked across 3 states.

The solitary juvenile crane that had been near Alma in southcentral
Nebraska near the Kansas border resumed migration on December 5th despite
strong southwest winds.  It had been at that same location since at least
October 15, so it was not the juvenile from the family group reported in
migration near Alma. The crane’s roost pond froze up on the December 4th
and presumably was a factor in the chick’s decision to continue the
migration.  It has not been reported since it left Alma.

Sightings near Aransas

Whooping cranes are showing up in unusual places this fall presumably
related to food shortages and the need to seek fresh water to drink.  On
December 5th around mid-morning, a single whooper was seen flying near
Colomo Creek about 1/3 mile west of FM 1289.  Coloma Creek empties into
Powderhorn Lake and is located southwest of Indianaloa, Texas north of
Aransas.

In the farm fields between Austwell and the refuge, whooping cranes have
been sighted among the 600+ sandhill cranes utilizing different fields as
follows:
          group    dates
remarks
      0+1     November 19 – December 8           juvenile whooping crane by
itself
      4+0     November 10-14
      1+0     November 18-20
      2+1     November 23                                   presumed new
arrival from the migration
      2+0     December 2-8
      2+1     December 9                                     new arrival or
returnee from Aransas marshes?

Fourteen different whooping cranes have been seen at wild game feeders this
fall.  Locations of the feeders on private property include just north of
the refuge headquarters, and three locations on the Lamar Peninsula.

Habitat use

Cranes on the flight included 24 observed at fresh water sources, 16 on
burned uplands, 4 on unburned uplands, and 3 in open bay habitat.  On a
boat trip over to Matagorda Island on December 11th, I noted two pairs of
cranes feeding in open bay habitat in Sundown Bay.

Items of interest

On December 1st, I picked up a very emaciated whooping crane from near a
water hole by the refuge boat ramp. The crane could not stand and after
capture was having difficulty holding up its head.  The crane died while I
was driving it to a veterinarian in Port Lavaca.  The bird was shipped to
the National Wildlife Health Center in Madison, Wisconsin and was
necropsied the next day.  The crane was a 2-yr-old subadult male, extremely
emaciated, with a bad left “knee”.  Organisms are being cultured from the
knee to see if it was badly infected that could have been making the bird
very sick and limiting its food intake.  There was no other indication of
disease, although additional tests are being conducted.  A whooping crane
was observed in Saskatchewan in the fall migration with a severe limp of
the left leg and could well have been the bird that died at Aransas.

Food sources for whooping cranes seem very low this winter, primarily due
to the summer drought.  I expect to confirm a record number of whooping
cranes at Aransas this winter, but the flock will probably experience
additional mortality.  A blue crab count conducted by refuge volunteer
Katherine Cullen on December 1st found only 1 crab in an hour of walking
through the marsh.  However, observations by the tour boat captains the
first week in December noted some blue crabs were still available for the
cranes.  Only a few wolfberry fruits and flowers were seen during the crab
count.  Follow-up searches for wolfberries conducted on Matagorda Island
confirmed that this year’s wolfberry crop was lower than normal.  Tides
have been lowered by recent low pressure systems, and bay salinities remain
high at 30 parts per thousand.  Cut-off marsh ponds had salinities levels
of 43 ppt.


Tom Stehn
Aransas National Wildlife Refuge

birdRockport.com would like to express great appreciation to Tom Stehn at the