Whooping Crane Census Flight - January 29, 2009
The sixth aerial census of the 2008-09 crane season was conducted January 29, 2009 in a Cessna 210 piloted by Gary Ritchey of Air Transit Solutions of Castroville, Texas with USFWS observer Tom Stehn. Weather conditions were good for the census, but overcast skies and haze made viewing less than ideal for 2 hours in the morning and 1 hour in the late afternoon. The middle of the day was gorgeous.
Recap of cranes (262) found at Aransas on the aerial.
| |Adults + |
| |young |
| Refuge | 54 + 9 |
| Lamar | 19 + 4 |
| San Jose | 51 + 5 |
| Matagorda | 80 + 10 |
| Welder | 26 + 1 |
| Flats | |
| farm | 3 + 0 |
| fields | |
| Total |233 + 29 = |
| |262 |
Whooping Crane Numbers
The estimated peak winter flock size remains at 232 adults + 38 juveniles = 270 total. Movements of the cranes to upland areas and water holes as well as their use of unusual locations this winter continues to make it very difficult to find and count every crane. A total of 262 cranes were tallied on the census, and it seems probable that the East Welder Flats family was overlooked.
Two dead whooping cranes have been picked up this winter - both were emaciated. In addition, the crane distribution indicates some additional loses may have occurred. The South Sundown Island juvenile has been missing for a couple months and is presumed dead. The Mustang Slough juvenile that separated from its parents and was foraging along the refuge tour loop has not been seen since January 10th after wandering north of the refuge. Only 29 out of the 35 juveniles I had expected to find were located on the census. This probably indicates some additional mortality of an unknown number of chicks has occurred. Also, in two instances, a single adult with its juvenile was encountered with no second adult crane in the vicinity. This could indicate adult mortality, although sometimes one of the adults is off in another territory in a territorial encounter. One more juvenile has split off from its parents. A solitary juvenile was observed on the very south end of the crane range on San Jose Island. I estimate the current flock size to be 231 adults + 34 juveniles = 265, but this is not a solid figure.
Cranes on the flight included 27 observed at fresh water sources, 33 on burned uplands, 31 on unburned uplands including shell roads, 18 at game feeders, and 40 in open bay habitat. At Welder Flats, 25 of the 27 cranes observed were in open bay habitat mostly foraging along the edge of the GIWW. Tides were extremely low the week of January 22nd. Much of the marsh on San Jose Island consisted of dry mudflats. Food sources for whooping cranes continue to be very low this winter, primarily due to the summer drought. With food shortages continuing in the salt marsh, crane use of uplands as well as a notable shift to open bay habitat has cranes staying off their territories. This makes it very difficult to determine the identity of pairs and family groups and leads to much uncertainty during the census count.
With the continuing food shortages for the cranes, refuge staff conducted two prescribed burns the week of January 26th. On the census flight, 30 cranes were observed foraging on the recent burn on Matagorda Island. Eight cranes were seen the day after on a refuge burn conducted on January 29th.
Due to the food shortage in the marshes, the refuge has begun an experimental supplemental feeding program. Seventeen game feeders have been placed near waterholes at approximately 3-mile intervals along refuge roads adjacent to the crane marshes on Aransas and Matagorda Island NWRs. Five whooping cranes were near these feeders on the census flight. Despite cranes presumably seeing the spread corn as they make daily flights to water, use of the feeders during the first week of use was characterized as "ight". Remote cameras and additional field observations will help determine how much the feeders are used in the future.
Items of interest
The whooping crane juvenile wintering near Hennesy, Oklahoma apparently continued its migration sometime after January 25th after its roost pond froze over during a cold front on the 26th. Its whereabouts are currently unknown.
The search area at Aransas has been expanded this winter since the cranes are showing up in unusual places. The 21 whooping cranes found on the Lamar Peninsula (18 at feeders) is as record high. A group of 4 adults was sighted in the interior of the Lamar Peninsula southwest of the Johnson Ranch in a location I have never flown over before. The group presumably was visiting a game feeder in front of a residence. They were difficult to spot from the air due to the big trees.
Sightings near Aransas
Whooping cranes are showing up in unusual places presumably related to food shortages and the need to seek fresh water to drink. On today's flight, 3 adults were in a former fish farm impoundment on the Bauer property south of Austwell along FM 774. Two cranes were at a game feeder north of Holiday Beach along Highway 35. One whooping crane was confirmed present near Oso Bay in Corpus Christi on January 13th. It was at game feeder in a location where a whooping crane had also been present in fall, 2005.
Tom Stehn, 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.