MONTGOMERY, ALA. — The annual migration of juvenile whooping cranes from Wisconsin to Florida has stalled in Alabama over a Federal Aviation Administration regulation.

The ultralight airplanes that lead the chicks to wintering grounds in Citrus County, Fla., were grounded after someone complained the pilots were being paid in violation of federal rules.

Operation Migration spokesman David Sakrison said nine migrating birds are safe in enclosures in Franklin County. They have been there about two weeks, but he hopes the regulatory issue can soon be resolved and the birds can resume their journey.

“They’re grounded,” Sakrison said Thursday. “It’s unprecedented. This is an administrative matter we’re trying to work out with the FAA.”

Operation Migration is the U.S. Fish and Wildlife Service’s partner in the annual migration to imprint the flight path on the young birds that winter in the southern United States, but return north on their own to breed and raise chicks.

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