Whooping cranes have begun their spring migration from Aransas National Wildlife Refuge in Texas to their nesting grounds in Wood Buffalo National Park.
The Whooping Crane Conservation Association, a Texas-based organization working closely with Aransas and the U.S. Fish and Wildlife Service, hoped to see the crane population rise to a record of more than 300 birds, but high winds and low cloud cover in February made getting an accurate aerial census challenging.
The cranes also made adjustments to their southerly migration patterns, and not all of them made it to the Texan wildlife refuge. For the winter, they were dispersed across Texas, Oklahoma, Kansas (a new stop for them), Nebraska and South Dakota. According to Aransas staff, the birds are now moving north.
“They’re moving pretty rapidly, and you can’t do any more than guess where they are,” said Chester McConnell, trustee emeritus at Whooping Crane Conservation Association, who has been with the organization for the last 15 years. McConnell regularly gets updates on whooping crane migration from people in the birds’ flight path.
Current estimates indicate about half of the whooping cranes are now flying north, and some have already been spotted in Canada, McConnell said. At last official count, there were 295 of the endangered whooping cranes.
The Aransas National Wildlife Refuge is still waiting for final reports on three whooping crane carcasses recovered since December. The National Wildlife Health Center (NWHC) reported the first bird, found Dec. 7, 2011, had a systemic blood infection common in birds that has been known to cause death. The NWHC has not yet completed its analysis of the carcass. A report on the cause of death of the second carcass, recovered Jan. 18, is still forthcoming. The NWHC’s necropsy of the third carcass, found Feb. 29, was inconclusive because of damage done by scavengers, but several strains of bacteria were discovered in the bird’s bone marrow.