November 25, 2008
The second aerial census of the 2008-09 crane season was conducted November 25, 2008 in a Cessna 210 piloted by Gary Ritchey of Air Transit Solutions of Castroville, Texas with USFWS observers Tom Stehn and Darrin Welchert. Weather conditions were ideal during the 5.4-hour flight with sunshine and light winds. Located were 228 adults + 38 juveniles = 266 total. This 266 total matches the peak population in the 2007-08 winter (but keep reading!).
Recap of cranes (266) found at Aransas on the aerial:
| |Adults + young|
| Refuge | 65 + 11 |
| Lamar | 7 + 3 |
| San Jose | 51 + 7 |
| Matagorda | 85 + 15 |
| Welder | 20 + 2 |
| Flats | |
| farm fields| - |
| Total |228 + 38 = 266|
Explanation of numbers located and additional cranes in the flock
Due to considerable crane movements during the flight, it was difficult to pin down the exact number of whooping cranes present. Eight-six cranes were found in uplands (45 at fresh water sources and 41 on coastal prairie). Such movements make it possible to double-count cranes as well as completely miss cranes as they move to and from the marshes. For example, a group of 8 adults, 4 juveniles and 1 subadult was found at one waterhole on Matagorda Island, and 24 whooping cranes were on a prescribed burn on Matagorda Island. Crane presence on uplands also makes it very difficult to identify specific territorial cranes since they are not in their marsh territories.
In addition to the estimated 266 counted, the following additional cranes presumably can be added to the estimated flock size:
2 whooping cranes in central Kansas
1 whooping crane juvenile seen in the farm fields south of Austwell, TX on Nov. 20-21st
2 family groups (4 adults + 2 chicks) believed overlooked at Welder Flats.
This brings the unofficial estimated flock size to a RECORD 234 + 41 = 275!
Future flights will try to confirm this estimated total.
Additional cold fronts reached the Texas coast on November 15, 20 and 24 that enabled an estimated 27 cranes to reach Aransas since the previous census on November 14th. Sighting reports in the migration corridor have nearly come to a halt. The National Tracking office in Grand Island, Nebraska reports only the 2 whooping cranes still in central Kansas. The most recent sighting before that was a family group in Nebraska on November 17th. However, it is well documented that some whooping cranes make it to Aransas in December every year. With the one known sighting in Kansas, it is very likely that low numbers of additional whooping cranes are in migration since most whooping cranes stop in isolated areas and never get reported.
Items of Note:
The 38 juveniles seen on the census flight indicates survival was very good from the 41 juveniles located in Canada in mid-August. With one additional juvenile seen November 20-21 with sandhills in the farm fields north of the refuge and possibly 2 family groups overlooked at Welder Flats on the flight, it's possible that 41 juveniles can be accounted for. Pinning down that number is a priority on future flights. The juvenile whooping crane was seen in a flock of about 600 sandhills on November 20-21 south of Austwell, Texas about 2 miles north of Aransas. One day, it was about 500 yards from a single adult whooping crane, but at opposite ends of the sandhill flock. The two whooping cranes flew separately at sunset to roost at the Refuge's Burgentine Lake. It seems likely that this juvenile had migrated with its parents all the way to the refuge's Burgentine Lake. In the commotion within a large flock of sandhill cranes, the juvenile presumably got separated from its parents that probably flew on to the salt marshes. The farm fields where the juvenile was at is about 9 miles from the nearest wintering whooping crane territory, so it is unknown whether the juvenile will continue to winter with sandhills or whether somehow it might encounter other its parents if it starts wandering. In the meantime, it looked fine.
One pair has arrived with twin chicks. This family (Klewi-20 in Wood Buffalo NP / Johnson Ranch pair at Aransas) that winters on the Lamar Peninsula has brought twin chicks to Aransas 3 times in the 12 years (1997-2008) since the egg pickup ended. They have brought 6 single chicks to Aransas during that same time period. That adds up to having brought one or two chicks to Aransas 9 out of the last 12 years. They have brought a total of 12 chicks to Aransas in the last 12 years. They have been the most productive pair during the past dozen years! They arrived about 9 AM on November 15th aided by a strong cold front. A single-chick family landed next to them about 5 minutes later that presumably had migrated with the twin family. The territorial Johnson Ranch male within 20 minutes had re-established his territory, scattering the other family and the 9 subadult cranes that had been present. The 16 cranes present that morning on the Johnson Ranch set a record high for most whooping cranes ever on the Lamar Peninsula. One bird in the subadult group of 9 flew with one leg hanging down. No limp had been noticed when that bird had been observed walking. Perhaps this was the crane reported with an injured leg in the fall migration in Saskatchewan.
The conditions at Aransas this winter do not look very good. The wolfberry crop seems notably lower, perhaps a result of the summer drought. Although some blue crabs were found on a count conducted November 10th, the cranes initially seemed to be foraging more on fiddler crabs. This suspected minimal amount of food resources was indicated by the 41 whooping cranes seen on uplands during today's census flight. A prescribed burn of around 2,500 acres conducted on Matagorda Island on November 15th held 24 whooping cranes, with 17 on unburned uplands. The use of unburned uplands this time of year is indicative of less than ideal food resources in the marsh. Bay and marsh salinities are around 30 parts per thousand, forcing the cranes to make daily flights to freshwater to drink. Forty-five cranes were found at fresh water sources during the census flight.
Tom Stehn, Whooping Crane
U.S. Fish and Wildlife Service
P.O. Box 100
Austwell, TX 77950
(361) 286-3559 Ext. 221
fax (361) 286-3722