The arctic cold front which has covered Idaho in recent days has stalled an effort to save trumpeter swans in eastern Idaho.

Rod Parker, regional spokesman for the Idaho Fish and Game Department, said sub-zero temperatures and extreme wind-chill readings led to numerous cases of frostbite and a number of vehicle breakdowns."You can't put people out in those conditions," Parker said. "Right now it's just not worth the physical risks."

The cold snap interrupted what has otherwise been a very successful program, said Ruth Shea, regional biologist for Fish and Game.

So far, 283 birds have been trapped by officials from Fish and Game and the U.S. Fish and Wildlife Service, said Shea, who has tracked trumpeters for 14 years.

On Friday, Shea participated in an aerial survey of the Island Park area and counted 777 swans. A separate ground survey at Red Rock Lakes Wildlife Refuge in Montana counted 230 birds.

Traditionally, 2,000 swans winter in the greater Yellowstone area. Of that, 700 normally stay in the Harriman-Last Chance area and about 450 swans winter at Red Rock Lakes.

The number of birds in the Island Park area still is far more than the area can support, said Shea. Last summer, Shea said there was only enough vegetation in the Harriman-Last Chance area for 100 birds to survive the winter.

Shea stands by that estimate, and she is not optimistic about the birds that stay in the Harriman area.

"Swans that stay in that area have very little chance of survival," she said.

While the cold weather has been rough on the trappers, Shea said it may be the best for the swans. She said most of the water in the area is now frozen solid.

"It may force the birds to get out of the area while they are still healthy," she said.

Shea said there is no food for the swans in the Island Park area and that a gradual freeze would allow the birds to linger and get weak.

Shea said the trapping program will be put on hold until the cold snap ends. When the temperatures begin to moderate, she said officials will again fly over the area.

"Right now we are going to sit back and see what the birds do on their own," she said.