PONTIAC - Ultralight airplanes leading 14 rare whooping cranes from Wisconsin to Florida bypassed a scheduled stop near Pontiac on Friday.

Optimum weather conditions allowed the caravan to fly from near Sheridan in LaSalle County to an undisclosed site in Piatt County, a distance of about 110 miles.

"When they've got a tailwind, they have to take advantage of it," said Heather Ray, a spokeswoman for Operation Migration, an effort to reintroduce the rare birds into the wild. "That's just the nature of the beast."

Headwinds had halted progress in LaSalle County since Tuesday. Breezes must be light to permit the birds to draft off wind currents the wings of the four aircraft create.

The cranes were hatched this year and raised at Necedah National Wildlife Refuge in central Wisconsin, where the migration began Oct. 17. They will take 23 days in the air to cover 1,285 miles before reaching Chassahowitzka and St. Mark's national wildlife refuges on Florida's Gulf Coast, where they will spend the winter.

Operation Migration began to reintroduce whooping cranes into the wild in 2001. This is the first time the migration route has passed over Central Illinois. In past years, the route turned north of the Illinois River and went east to Indiana before turning south again.

The population of the endangered birds fell to under 20 cranes by World War II. Operation Migration has introduced 69 birds into the wild. The goal is to reach the self-sustaining level of 125 individual birds and 25 breeding pairs.

Another flock of cranes numbering about 220 and migrates between Texas and Canada.

Watch for updates at www.operationmigration.org.