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.
Whooping Crane Coordinator
U.S. Fish and Wildlife Service
P.O. Box 100
Austwell, TX 77950
(361) 286-3559 Ext. 221
fax (361) 286-3722
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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: firstname.lastname@example.org. 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