LOUISVILLE, Ky. -- The effort to save an endangered species has hit a bump in Kentuckiana.

A five-month-old whooping crane is missing. It was last seen near the Ohio River en route to Shelby County, Kentucky. The cranes are learning their migration led by ultralight aircraft from Wisconsin to Florida.

The missing crane is one of only about 500 on earth.

Operation Migration lost track of the bird on Friday morning somewhere between Jackson County, Indiana and Shelby County, Kentucky. Since then, they've been trying to hone in on a transmitter on that bird both by ground crews and crews by air. Missing, one five-month whooping crane, number 733.

"It was nothing I recognized," says Jerry Hancock. "It was just sitting in the cornfield."

A number of tips have been coming in.

“It caught my eye as we sat at the light.” Jim Preuett called our newsroom. “I just kept looking at it and thinking, ‘What is that?’”

With so few whooping cranes in existence, most people wouldn't know one if they saw one.

“I don't know,” says Preuett. “After seeing the picture, the neck was not as pronounced, so I’m a little less convinced that what I saw was the bird.”

“Well, the thing is, a crane will fly... This bird is landing, so its neck is curved, but a crane flies with its neck extended and feet extended,” says Operation Migration’s Joe Duff.

The whooping cranes are fitted with tiny transmitters, so the search teams are listening for #733's signal. A beep from our camera gave them momentary false hope. They've exhausted the obvious places to look

“It's not a total loss unless the bird is killed by a predator. But, we'd like to get him back because we spent all spring training the bird, and all summer working with him and led him this far,” says Duff. “We have a huge investment in this bird so far.”

The search continues, but it can't go on forever. So, Operation Migration plans on taking off from Washington County, Kentucky sometime Tuesday morning.

If you think you've spotted missing crane #733, do not approach the bird. Please call 1 800 675 2618.

Operation Migration was founded in 1994 as a non- profit charitable organization by Bill Lishman and Joe Duff, one year after the two men used ultralight aircraft to lead a small flock of geese from Ontario, Canada to Virginia.

That garnered worldwide attention that led to the making of the hit movie Fly Away Home with Columbia Pictures.

Web story produced by Jay Ditzer.