TO: Division of Endangered Species, USFWS, Albuquerque, NM
FROM: Whooping Crane Coordinator, Aransas NWR, Austwell, Texas
SUBJECT: Whooping Crane Census at Aransas
An aerial census of the Aransas NWR and surrounding areas made 10/22/98 did not locate any whooping cranes. The flight was made in charter aircraft with Tom Taylor, pilot and Tom Stehn as observer.
The first arrival at Aransas is going to be at least one week later than the average of October 16. Last year, the first whooper arrived on October 21.
The peak population last winter was 152 + 30 = 182. With 24 chicks sighted in WBNP in mid-August, 190+ whooping cranes are expected to arrive at Aransas this fall.
The flight was notable from the high tides present. The flooding Guadalupe River (9 feet over Highway 35 north of the refuge) is pouring huge amounts of freshwater into the bays and raising water levels. Bay salinities were measured at zero on October 21.
Many of the whooping crane marshes were flooded. Water levels were the highest I have observed on a whooping crane flight in the past 15 years. All of the marsh vegetation on Matagorda Island and Welder Flats was completely underwater. To look for whoopers, only one transect was required on Matagorda along the upland edge of the marsh where egrets had congregated to forage. This demonstrated why a large amount of debris accumulates on this upland border. Even the road down the center of Matagorda was flooded north of Panther Point. The road into the Cliburn cabin at Welder was also impassable.
Four barges were parked at the Welder Flats mooring, possibly due to flooding of the Colorado River further along the channel.
The freshwater should be beneficial to the whooping cranes since it benefits reproduction of blue crabs, the main food source for the whoopers. Late summer rains from two tropical storms also helped the refuge marshes with much needed moisture. The refuge has received more than 15 inches of rain since mid-August.
There have been reports of whooping cranes as far south as Salt Plains NWR in Oklahoma. Thus, the population is currently strung out between Saskatchewan and Oklahoma. It always amazes me how variable the timing of the migration is, with all birds having their own inner clocks and itineraries.