Whooping Crane Recovery Update.
"The backbone of recovery efforts has really been the Aransas/Wood Buffalo flock," said Tom Stehn, the U.S. Fish and Wildlife Service's National Whooping Crane Recovery Coordinator. The flock is so named for the 2,500-mile (4,000-kilometer) journey it makes every April and October between its wintering grounds at Aransas National Wildlife Refuge (NWR) on the Gulf Coast of Texas and its nesting grounds at Wood Buffalo National Park in the Northwest Territories, Canada. The direct descendants of the original 15 or 16 birds typically depart in pairs or small family groups for their northward migration. "This particular flock has been making considerable progress, growing in numbers at around four percent annually, and is now at a record 187 birds."
The other wild population is the non-migratory flock established in Florida. Since 1993, 20 to 30 juvenile captive-raised whooping cranes have been soft-released onto the Kissimmee Prairie of central Florida each year. These birds are raised by handlers wearing crane costumes so that the birds do not imprint on people but learn the behaviors they need to survive in the wild. Whooping crane pairs in Florida first laid eggs in 1999, and two chicks hatched out in 2000 but did not survive to fledging. Bobcat (Felis rufus) predation remains the primary threat to this population, which currently numbers about 78 birds.
Recovery biologists now are planning to introduce a third flock of whooping cranes into the wild. An ultralight aircraft will give the birds their first lesson in migration. Once the cranes are taught a migration pattern their first fall, they should follow the same route for the rest of their lives. The plan is to have the birds summer at the Necedah NWR in central Wisconsin and winter at Chassahowitzka NWR on the west coast of Florida. Biologists hope that a migratory flock of about 125 whooping cranes can be established over the next 12 years.
The Service's recovery efforts would have been fruitless without the help of the Canadian Wildlife Service, which has five members on the international whooping crane recovery team. Both countries have been working together ever since they realized how close the whooping crane was to extinction. Starting in 1966, Canadian biologists collected the eggs from Wood Buffalo National Park that made the captive propagation program possible. In 1985, both countries signed a Memorandum of Understanding to improve coordination and cooperation. Canada houses a flock of cranes at the Calgary Zoo as part of the recovery plan.
Whooping cranes formerly bred within a range bordered by central Illinois, northern Iowa, western Minnesota, northeastern North Dakota, southern Manitoba, and Saskatchewan. Some wintered along the coast in New Jersey, South Carolina, and possibly other southeastern states. Establishing an eastern migratory flock and the Florida non-migratory flock would meet the recovery goals for downlisting by the year 2020: two self-sustaining flocks besides the Aransas/Wood Buffalo flock, each with 25 nesting pairs, that persist for at least 10 years. Requirements for delisting have not yet been determined.
Ben Ikenson is a Public Affairs Specialist with the Service's Albuquerque Regional Office.
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|Publication:||Endangered Species Update|
|Date:||May 1, 2001|
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