The three were among the 10 wolves from three different packs that were tranquilized, collared, and released over the past two weeks as part of a long-used research program, the Park Service said. These deaths were the first since 1994 of a darted and collared wolf, agency officials added.
About 100 wolves live in Denali, and the park is considered a good location for watching the elusive animals.
"There are relatively few places where you can see a wolf in the wild, and Denali is one," said Park Service spokesman John Quinley, who added an agency review of the research program by a panel of experts has been launched. Results of the review are expected by the end of April.
Over the weekend, the Park Service had given permission to the Alaska Wildlife Alliance, a private group to drop food to one other wolf that was tranquilized and outfitted with a collar that was still alive. But on Monday, it was spotted eating caribou meat, "which is a good sign and we are not doing supplemental feeding at this point," Quinley said.
Preliminary necropsies performed on two of the dead wolves indicate they had been weakened by infection, said Gordon Olson, head of Denali's research program.
In the third case, a yearling wolf was found dead with two adults it had been traveling with, Olson said. The yearling was essentially consumed, making a necropsy impossible.
But Dr. Paul Joslin, wolf biologist and the Wildlife Alliance's executive director, doesn't believe the wolves died of infection.
"It is unlikely that three different animals from three different packs suffered from infection which the Park Service claims has contributed to their deaths. We suspect that it is more likely that all three died from a drug overdose," Joslin said.
The dead wolves were released in three separate efforts. Three wolves from the Otter Creek pack were tranquilized, collared, and released on March 14, with one of them found dead on March 17.
Also that same day, one wolf from another pair that had been tranquilized, collared, and released was discovered dead at the release site by a tracking flight, while the other was healthy.
The third incident involved two wolves from the East Fork pack captured last week near Savage River. One of the wolves was found dead at the capture site a day later.
Over the 15 years of the program at Denali, researchers have captured and released more than 300 wolves before the recent effort, the Park Service said. The three deaths this year brings the total capture-related deaths to eight, the agency added.
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