Greetings all!
The following report is forwarded with permission from Tom Stehn, USFWS
biologist and US Whooping Crane Coordinator.
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An aerial census on 11 January, 2006 of the Aransas National Wildlife Refuge and
surrounding areas estimated the number of whooping cranes present in the
Aransas-Wood Buffalo flock at 189 adults + 29 young = 218 total. This total
includes one whooping crane in extreme South Texas in Hidalgo County, and one
whooping crane last seen east of Pierre, South Dakota on January 3rd. One adult
and one juvenile have died this fall at Aransas, accounting for a peak flock
size of 190 + 30 = 220. One whooping crane was reported January 8th at Muleshoe
National Wildlife Refuge in the Texas Panhandle. This report looks promising but
hasn't been confirmed. Could it be the whooping crane that had been in South
Dakota?
Recap of cranes observed on the flight: (211)
adults + young
Refuge 59 + 10
Lamar 5 + 0
San Jose 42 + 4
Matagorda 59 + 11
Welder Flats 17 + 4
Total 182 + 29 = 211
Remarks: Flight conditions and visibility were excellent allowing for a complete
census. Crane numbers in all parts of their range were as anticipated except for
coming up short about 5 subadults on the south end of Matagorda Island. These
were presumably overlooked. Movements of the cranes to freshwater and/or uplands
made the census more difficult. However, with the excellent visibility and
thorough census, I am convinced I have a reasonably accurate picture of the
flock. With 30 chicks that made it to Aransas (one died after arrival), the
population of 215 in the spring of 2005 could have reached 245 if there had been
no mortality. Instead, the estimated peak population of 220 this fall indicates
that 25 whooping cranes at Aransas in the spring of 2005 failed to return in the
fall. That is 11.6 % of the spring, 2005 population. With annual mortality
averaging about 9.8%, it is apparent that mortality between spring and fall was
higher than average and resulted in only the small increase in flock size. Only
one carcass was recovered during this period of a 28-year-old female crane in
Saskatchewan in the fall. I have no explanation for why mortality was greater
than average.
Today's flight really helped to finalize the presence of territorial pairs,
including two new duos expected to nest in 2006. In addition to documentation of
habitat use, there were three important findings on today's flight about
specific cranes.
a) The juvenile in the N. Pipeline Flats territory, not located last week and
feared dead, has re-appeared and was right next to the widowed adult. Last week,
it must have been separated from the female and/or been sitting down in the
marsh and overlooked. Thus, mortality documented at Aransas this fall equals one
adult and one juvenile, and not a second juvenile as reported in last week's
report.
b) The single adult family first documented present December 21st may have
re-paired. They were seen on today's flight as two adults with the juvenile with
typical spacing of a family group. They were first seen on the refuge uplands
south of Sundown Bay and then flew to the edge of the marsh near Big Lake. This
juvenile seems to have more rusty body feathers than some of the other juveniles
and can be identified from most other family groups.
c) A pair of banded cranes has re-paired since last winter. Male crane nil-hs
(formerly RwR-nil 1978 with an unbanded mate) is now paired with y/g-Y (1987)
and has a juvenile. They are staying on the extreme north end of nil-hs's
traditional Middle Matagorda Island winter territory. This territory is located
next to the Panther Point territory where y/g-Y used to winter with Y-nil
(formerly Y-G 1985). I have not seen Y-nil this winter. However, there is an
unbanded duo wintering in the traditional Panther Point territory, so perhaps
the one remaining band has fallen off Y-nil and the crane is still alive with a
new mate. Perhaps nil-hs lost his mate and re-paired with a younger female from
an adjacent territory.
Many cranes were located on today's flight in places they normally don't use.
Observations of habitat use on today's flight included 12 cranes at freshwater
sources, 12 cranes foraging on uplands, and 61 cranes in open bay habitat,
nearly triple the amount of open bay use documented the previous week. No cranes
were on prescribed burns despite one recent burn on San Jose. The amount of open
bay use has increased substantially as tides have remained low and were the
lowest observed so far this winter on any aerial flight. Large areas of mudflats
on San Jose Island were exposed, as were pond margins throughout the wintering
range. Cranes are out in open bays presumably foraging on clams and other
invertebrates such as blood worms and mud shrimp buried in the substrate.
Fifteen of the 21 cranes at Welder Flats were in open bay habitat, including 11
foraging on the shallow edge of the GIWW. Six whooping cranes were associated
with sandhills cranes on bare dirt areas rooted up feral hogs on Matagorda
Island uplands, and 1 crane on San Jose was on a disked firebreak with sandhills.
Salinities are very high due to the drought experienced by central Texas the
past 9 months that has been related to the global weather pattern known as La
Nina. Cranes are being forced to fly to freshwater sources to drink. This is a
tough part of the winter for the whooping cranes, but with conditions similar to
what they have faced before, typical of January.
Tom Stehn
Whooping Crane Coordinator
U.S. Fish and Wildlife Service
Aransas NWR
P.O. Box 100
Austwell, TX 77950
(361) 286-3559 Ext. 221
fax (361) 286-3722
E:mail: tom_stehn@fws.gov
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Where applicable, CWS stands for Canadian Wildlife Service; USFWS is US Fish and
Wildlife Service. Crane monitoring involves cooperative efforts and support by
both countries, plus many volunteers and non-profit organizations along the way.
Anyone wanting to contact Tom about the report or the whooping crane projects
can reach him via email at: tom_stehn@fws.gov. Other information, including
archived copies of these reports, can be found at the Texas Whooping Crane web
site at http://www.ccbirding.com/
Patty Waits Beasley
Corpus Christi, TX
email: patty@ccbirding.com
web: http://www.ccbirding.com/