A helicopter crew firing sedation darts last week at elk in Custer State Park saw a repeat of a lion attack that killed a sedated elk during similar operations last year.
This year, the elk cow elk survived, however, thanks to some timely interference from the helicopter.
“I tell you what, it was unbelievable to have this happen two years in a row,” said Chad Lehman, senior wildlife biologist for the state Game, Fish & Parks Department in the park. “We were just really happy that the guys in the helicopter were able to thwart the lion attack this year.”
The helicopter crew from Quicksilver Air, a company with bases in Alaska and Colorado, is helping state researchers with a study of elk reproduction and calf survival in the park. The Quicksilver crew fired sedation darts from the helicopter to subdue the elk and then picked up Lehman and other wildlife professionals for a ride to the elk.
“We were waiting for the shuttle when we heard the pilot say over the radio, ‘You guys aren’t going to believe this, but we just had a mountain lion attack one of your drugged elk,’” Lehman said. “We told them we could believe it, because last year we had a lion eat one of our drugged elk.”
The cow elk in the study must be sedated so vaginal implants as well as collars can be fitted to locate the animals after they give birth this spring. Their calves will be fitted with radio collars so they can be followed.
During the helicopter work last year, one of the cow elk hit with a dart was almost immediately attacked and killed by a mountain lion. Another elk was chased by a lion last year, the helicopter crew reported.
This year, a lion made a run at an elk Feb. 26. But this time, the helicopter pilot got involved, first buzzing low over the lion, which stopped and stared at the chattering machine but took off after the elk again.
So the pilot got more aggressive and dropped the chopper down to hover between the lion and the elk until the cat gave up and ran into the trees.
“Last year, that elk had been under the drug for a while. It was almost asleep,” Lehman said. “This year, the elk had just been darted, and the lion came out of thick timber to chase it. The guys in the helicopter did a great job of separating the lion from the elk.”
While researchers in adjoining Wind Cave National Park are working a management plan to reduce the size of the 700-elk herd there, CSP officials are trying to rebuild a herd that has fallen from more than 1,000 to about 150.
Additional hunting pressure in recent years substantially reduced adult elk numbers in the park, said Lowell Schmitz, a big-game biologist with GF&P in Rapid City. But lions are clearly having an impact on elk numbers, too. The lion attacks reflected during the helicopter work show that. So did the first year of the study on elk-calf survival.
Thirty elk calves born last spring were located with signals from transmitters that had been implanted in pregnant cows during the previous helicopter work. The calves were fitted with radio collars.
Eleven of the collars got caught in fences or were otherwise disabled. Of the 19 remaining collared calves, 16 were confirmed as killed by lions. Two were listed as unknown predation. Only one of the 19 remains alive.
“That little guy still has several months to go to make it to a year old,” Schmitz said.
Lehman said researchers presume the other 11 calves suffered the same percentage loss to lions as did the 19 calves that were followed in the study. But that statistical assumption can’t be confirmed or disproven.
The impact of lions on elk calf survival is clear, however, Lehman said.
Researchers will watch the calf study results this year to see if the recent lion season, which killed four lions in the park and several more outside nearby, will reduce predation on elk calves.
Meanwhile, one elk cow that might have been killed is still alive. Lehman is happy about that.
“I don’t want to put elk in harm’s way by doing this research,” he said.
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