CHASSAHOWITZKA — They've endured snow and frigid weather.
They've made it through high winds and thunderstorms.
But the rare whooping cranes that migrate annually from Wisconsin to Florida have been grounded by an unlikely foe:
The nine birds comprising the so-called Class of 2011 made it as far as Franklin County in northwest Alabama, where they are penned and waiting for the Federal Aviation Administration to decide whether the unique wildlife reintroduction program can be exempted from a rule for pilots that went into effect in 2008.
The issue concerns whether Operation Migration's pilots — who have been slipping on crane suits and crawling into ultralights to teach the young birds the migration route from Wisconsin to Florida for 11 years — are flying for hire or for the benefit of a nonprofit organization, said David Sakrison, a director on the board of Operation Migration. The ultralights are licensed as light sport aircraft under rules that took effect in 2008. Federal regulations prohibit craft licensed that way to be flown for hire or for business activities.
With the issue that has arisen, it remains unknown how this year's group will be delivered to wintering grounds at St. Marks National Wildlife Refuge in the Panhandle and the Chassahowitzka National Wildlife Refuge, straddling Hernando and Citrus counties.
In a posting on the Web on Thursday, Sakrison announced the suspension of the migration and noted that "we are working with our … partners to develop a contingency plan for completing the migration without aircraft if necessary.''
The FAA scrutiny came after a former Operation Migration employee filed a complaint. The FAA office in Milwaukee told Operation Migration officials that the migration could go forward. But when a second complaint was filed at the regional level, the agency opened an investigation.
Operation Migration officials have acknowledged that the pilots are paid for a wide range of nonflying activities; they maintain, however, that the pilots fly for the nonprofit organization as unpaid volunteers.
In November, each pilot received a letter of investigation. After speaking with the FAA, Operation Migration officials agreed to cease flying in late December until the issue of a waiver could be settled.
"The FAA is in support of this project and is working hard to resolve the matter in our favor," Sakrison wrote in his posting. "We appreciate their efforts."
Active discussions are ongoing about the waiver, according to Lynn Lunsford, an FAA spokesman.
"Sport pilots are flying for compensation, which is prohibited under the regulations. The pilots have voluntarily grounded themselves," Lunsford said. "The FAA has not suspended Operation Migration. … The pilots themselves have decided to cease flying while the organization waits for an answer to its requested exemption from the regulations."
Sakrison noted that granting the waiver would be based on factors such as safety and the public good. Operation Migration, he wrote, "has never had an aircraft-related accident and its contribution to wildlife conservation is well established."
The experimental eastern whooping crane flock now tops 100 birds, many of which followed the ultralights in their first migration to Florida.
Barbara Behrendt can be reached at email@example.com or (352) 848-1434.