Two Eagles Find Their Wings Once More After Illness : Wildlife: Mystery ailment had killed nine others. Survivors undergo month of training before being released to national refuge in Wisconsin.

Two bald eagles recovering from an unknown illness that killed nine others had to work out like athletes to regain their wing strength.

After more than a month under the tutelage of trainer Julie Johnson, the birds were released recently at a national wildlife refuge in western Wisconsin.

“The eagles took off, they flew really well and we haven’t spotted them since,” according to Amy Prochowicz, who works at the refuge.

Johnson, humane officer for Columbia County, ran the eagle workouts while caring for the birds at a rehabilitation center she operates from her home. Both eagles were released April 21 at Trempealeau National Wildlife Refuge on the Mississippi River about 30 miles north of La Crosse.

The first time the eagles attempted to fly after being caged, Johnson said, “They were out about 10 minutes and they were exhausted. They were totally out of shape.”

The eagles were fitted with leather “jesses,” or ankle harnesses, in mid-March and tossed into the air to fly. They were tethered by a 150-foot line.

After more than a month of workouts, the eagles could handle 1 1/2 hours of the flight exercise, showing they had regained the strength they need for survival.

“Out in the wild they fly continuously. They soar, they zoom, they have to hunt for food,” Johnson said.

The two birds were the only survivors of 11 eagles stricken by the unexplained illness in Sauk and Columbia counties in southern Wisconsin during January and February. The nine others were dead when examined at the National Wildlife Health Center in Madison.

The two survivors were initially treated at the center, where scientists have tried without success to determine what caused the illness.

After Johnson got the two recovering birds March 3, the first step was waterproofing their feathers by spraying them with water twice a day. Diet and weight were carefully monitored.

Food for the eagles included rats, mice, rabbits and fish, both live and dead. Live trout and minnows sometimes were placed in pans that went in the eagles’ cages for their meals.

“They can eat about 2 1/2 pounds of fish a day,” Johnson said.

Each of the eagles gained a pound while at her home, she said. When ready for release, the female weighed 11 3/4 pounds and the male 11 1/4 pounds.

The 1-year-old female had been banded as a baby in Upper Michigan. The 3-year-old male had not been banded before but was before his release.

Bald eagles, with a wingspan of about seven feet, were declared endangered in 1967 and remain a protected species under state and federal law.