20 February 2012

Study of Winter Cranes a New Challenge

The winter occurrence of whooping cranes along the central Platte River in Nebraska is a significant change in the behavior of this endangered bird.

Three adult cranes were present from January 27th to February 2nd, said Martha Tacha, a biologist at the Nebraska field office of the Fish and Wildlife Service in Grand Island. One prominent site they utilized was a river channel on the north side of Jeffrey Island.

The sighting of this species during the winter in Nebraska "certainly is unique," Tacha said. Their earliest date of occurrence having previously been February 7th.

Numerous Sandhill Cranes have also wintered along the central Platte.

There have also been Whooping Cranes at Quivira and Cheyenne Bottoms refuges in Kansas. Birds arrived in this region in late November, then never left and continued to be present in late January.

Along the Texas Gulf coast, there has been a dramatic decline in the number of cranes overwintering around Aransas NWR, their usual winter locale.

"It has been difficult for the whoopers at Aransas, due to drought conditions," Tacha said.

The federal agency tracks the occurrence of these cranes. Their effort started in 1975, with additional work done to document previous records. Records are maintained in a database.

"The results of occurrence situations this year will mean new challenges to censusing populations," Tacha said. "We don't have a good handle on the overall current population due to their movements this winter."

"If we can follow the crane's activities, we can better understand what they need to survive," Tacha said. "We need to learn more about how these cranes respond to challenges" influencing their longterm existence.

There are fewer than 300 Whooping Cranes in the flock which migrates through the Great Plains.