The U.S. Fish and Wildlife Service said it will stop supporting the use of ultralight aircraft to help young whooping cranes migrate from Wisconsin to Florida each fall.
Officials announced Friday that this season's ultralight-guided flights to the birds' winter home will be the last, the Milwaukee Journal Sentinel reported. The birds are guided to the Chassahowitzka Wildlife Management Area near Brooksville.
Operation Migration, the Canadian-based nonprofit group that has led the migrations for 15 years, has opposed the end of ultralights, saying the program has helped cranes survive. But Fish and Wildlife officials the birds haven't been successful in producing chicks and raising them in the wild.
The effort has spent more than $20 million to establish the flock that's distinct from a larger flock of whooping cranes migrating between the Texas Gulf Coast and northern Canada.
The final decision to end the public-private effort was made in Baraboo during a meeting of the Whooping Crane Eastern Partnership, according to Pete Fasbender, a Minnesota-based field office supervisor of the Fish and Wildlife Service.
"The real short answer is that we felt that this was in the best interest of the birds," Fasbender said.
Almost 250 whooping cranes have been released in Wisconsin since 2001. Fish and Wildlife officials say about 93 are currently alive, but only 10 chicks have survived to fledge.
Experts in crane biology have concluded that the use of aircraft and other human interaction are having a negative impact. Since 2005, the chicks that fledged and were born in the wild came from only five pairs of adults, the Fish and Wildlife Service said.
"Why aren't the others getting it?" asked Fasbender. "The common thread is this lack of parenting skills."
The partnership includes Operation Migration and staff from the Baraboo-based International Crane Foundation, the largest crane conservation organization in the world. Barry Hartup, director of veterinary service, said the crane foundation agrees with the changes, which include limiting human interaction with chicks and minimizing a practice where costumed humans help care for chicks.
"We have to find ways to reduce the element of artificiality," Hartup said.
The decision is a setback for Operation Migration, which has staff in northern Florida, just short of the final destination of St. Marks National Wildlife Refuge. The ultralight migration this year has lasted more than 100 days.
Joe Duff, chief executive officer of Operation Migration, posted a comment Saturday on the group's website that said: "It is sad to see the end of aircraft led migration. There will be many people who will be disappointed, and even a few who will celebrate. But those reactions are all about people and our mantra has always been, it's about the birds."