A whooping crane found dead in a farmer's field was a "senior citizen" with a colorful past that helped with studies of the rare birds, a Fish and Wildlife Service spokesman says.

The whooper, found Wednesday in a field west of the city, near Almont, appeared to have a broken neck, spokesman Ken Torkelson said. Biologists believe the bird had been dead for at least a day before it was found but they do not believe it was killed by humans, Torkelson said.

The carcass is being sent to the National Wildlife Health Center in Madison, Wis. for analysis.

"What caused the broken neck, we're not sure, and we may never know," Torkelson said Thursday.

A power line was about a mile away, but authorities do not know if that played a role, Torkelson said.

"It would be a first, but it's not impossible for that bird to have had a heart attack in the air and suffered a broken neck on impact with the ground," he said. "It could also have been a predator but there are no signs of that. If we had to guess, it appears to have come in a collision with something."

An identification band showed the bird hatched in 1983. Biologists say most whooping cranes do not live much longer than 20 years.

"It was still a very productive male, having brought six chicks to Aransas out of the last 10 years," Tom Stehn, the whooping crane coordinator for the Fish and Wildlife Service at Aransas National Wildlife Refuge in Texas, said in a statement.

The dead bird and its mate were equipped with radio collars in the early 1980s and were known as the "radio pair," Stehn said. Along with producing offspring, the pair provided valuable information for researchers, he said.

"He was not the granddaddy of the flock, but he was definitely one of the senior citizens," Torkelson said of the dead whooper. "He apparently he was still mated up this year and still could have produced offspring, so it's certainly a loss to the whooping crane flock."

Stehn also said the whooper found near Almont was involved in the "fastest whooper migration across the United States ever recorded."

The bird and its parents were in a flock of six whooping cranes that landed near Pierre, S.D., on Nov. 8, 1983, and were found on the Texas coast just three days later, he said.

"They were pushed by strong tailwinds and a low pressure system on their way south and must have flown pretty much nonstop," Stehn said.