Whoopers record largest numbers ever, despite the loss of four
By by Dianna Wray
March 2, 2011 at 5:05 p.m.
Updated March 1, 2011 at 9:02 p.m.
MORE ON WHOOPERSWhooping cranes mate for life, and live and travel in family groups.
This flock of whooping cranes has been travelling between Wood Buffalo National Park in the Northwest Territories of Canada and Aransas National Wildlife Refuge since the Ice Ages.
Once a whooper has made the 1,200 mile migration, they are able to make the trip on their own.
The whooping cranes have made it through the winter though not without some possible mortalities.
U.S. Fish and Wildlife Services whooping crane coordinator Tom Stehn conducted the sixth aerial survey of the cranes on Tuesday, counting 257 birds in the Aransas National Wildlife Refuge.
Stehn and U.S. Fish and Wildlife Services biologist Brad Stroble have concluded that four whooping cranes have died over the winter.
The birds stay in family groups, each in their separate territory in the refuge, Stehn said.
The flock size peaked with 283 birds over the winter. Despite the loss of four birds, the flock is the largest it has ever been with 279 birds.
Stehn and Stroble keep a close eye on the birds. When one of them is missing from the family group, they notice, Stehn said.
Stehn said one adult was missing from three crane families. The fourth crane family was missing the chick.
"If there's one adult with one chick, and there's no adult crane around, you usually see them on the edge of the territory somewhere," Stehn said. "They just don't split up during the winter. They're always together."
Though they haven't found any carcasses, whooping crane behavior is very predictable, Stehn said, and the birds are likely dead.
Also, current weather conditions are conducive for the birds to begin their migration back to Canada.
Right now, they are unsure of what may have killed the birds, Stroble said.
"There's always some mortality that occurs in any population. Whether this is natural mortality or something human related, we're not sure at this point," Stroble said.