BOISE, Idaho -- Federal agents in an airplane shot two wolves from a pack believed to have been preying on livestock in central Idaho, the first kills since state officials took over management of the predators earlier this month.

The adult male and female killed on Jan. 19 were from the Buffalo Ridge Pack.

On Jan. 15, members of the pack killed at least one calf in the pasture of a rancher in the Challis area near the Salmon River, U.S. Department of Agriculture Wildlife Services agents in Idaho told The Associated Press.

Wolf tracks were found around the carcass, the federal predator-control agency said.

Although the state Department of Fish and Game assumed day-to-day management of Idaho's 600 wolves from the U.S. Department of Interior as of Jan. 5, the federal government still assists the state with wolf predator control.

Idaho wolves are protected under the federal Endangered Species Act, but can be shot legally if they are preying on livestock.

Todd Grimm, a Wildlife Services district supervisor, said Friday his agency worked with state Fish and Game wolf coordinator Steve Nadeau, who gave agents permission to kill two wolves.

"As soon as we found out about the depredation, we called Steve Nadeau, to tell him we were investigating," Grimm said. "We did have traps and snares set. The wolves happened to be where the depredation had taken place" when an agent shot them from the plane.

Nadeau said he gave permission to kill the wolves after Wildlife Services determined that non-lethal measures wouldn't work.

Meanwhile, Fish and Game officials have released a study they say justifies killing dozens of wolves over the next five years in northern Idaho's Clearwater Basin, about 200 miles from the Buffalo Ridge Pack, to increase the number of elk in the area.

Biologists want to reduce the wolf population in the area from as many as 69 wolves to as few as 15 and keep it at that level. After five years, the effect on the elk population would be evaluated.

Public meetings are planned in Boise on Feb. 2 and in Lewiston on Feb. 7.

After the Jan. 19 shootings, the wolf carcasses were turned over to Fish and Game for analysis of what they were eating.

At least two of the remaining wolves in the Buffalo Ridge Pack are wearing radio collars.

Agents in the plane spotted another member of the pack, a wolf local ranchers refer to as "Blackie" due to the color of his coat, several miles from where the two wolves were shot.

Last February, two wolves from the same pack were killed by Wildlife Services agents after they were found to have preyed on cattle.

The same month, near the remote town of Mackay south of the latest killings, a wolf believed to be from the Copper Basin pack was shot by a rancher who received federal permission following attacks on his cattle.

In 2005, federal wildlife agents investigated 93 rancher complaints, with wolves confirmed or suspected of having killed 181 sheep, 18 calves, six cows and 11 dogs. That compares to 2003, when wolves were blamed for killing 118 sheep, 13 calves and six dogs.

Since wolves were introduced in 1995 to Idaho and Yellowstone National Park, they've multiplied to more than 900 in Idaho, Montana and Wyoming. Federal agents and livestock owners have legally killed more than 300 wolves in the region that were confirmed or suspected of having preyed upon livestock.

Environmentalists say the state should focus on improving habitat, not killing wolves.