A multi-year study tracking North Dakota’s mountain lion population indicates the number of big cats is trending downward.
In August 2011, the North Dakota Game and Fish Department, in conjunction with South Dakota State University, embarked on a $218,000 study funded by Pittman-Roberston excise tax money.
Stephanie Tucker, furbearer biologist for the Game and Fish Department, said the first phase of the study is in the books and a new three-year follow-up study will be launched this fall.
North Dakota is entering its 10th year of managed mountain lion hunting. This year, the season opens Aug. 29.
Tucker said one of the most effective methods of gathering data — particularly when dealing with a species new to certain areas — is to open a season on them.
“It’s kind of a reactive way to manage,” she said. Animals that have been hunted and harvested provide solid information like feeding habits and genetic background.
For the past decade or longer, mountain lions have been breeding in the state but also have been immigrating from South Dakota’s Black Hills.
Data from the study also has indicated at least two male lions have moved in from eastern Montana.
The first phase of the study tracked 22 mountain lions that were captured and either fitted with radio collars or ear tags.
Tucker said it focused on studying survival rates, food habits and home range and movement patterns compared to mountain lions in other areas of North America.
Of the 22 cats captured, seven males and seven females were fitted with radio collars and seven males and one female were ear-tagged.
Tucker said 18 of the cats that were captured for the study are confirmed dead by hunters or other means and the fate of the remaining four is not known.
The first year of the hunting season (2005-06), seven mountains were killed. The next four seasons, 11-12 cats were killed, until the 2010-11 season when 22 were killed.
The high came in 2011-12, when 31 cats were taken. The last two seasons, there have been
23 and 20 mountain lions killed, respectively. Tucker said those numbers reflect all forms of mortality, whether from hunters, road kill or protection of property.
Tucker said the first split season was three years ago, when seven animals were held back from the Zone 1 season quota for those hunting with hounds.
The state is divided into two mountain lion zones. Zone 1 is the Badlands area and Zone 2 is remainder of the state.
The Zone 1 season closes
Nov. 23 or when the 14-cat quota is reached, leaving the remaining seven in the quota for hound hunters, although any hunters can hunt them.
There is no quota for Zone 2.
Tucker said data shows that until 2011, the mountain lion population in Zone 1 was increasing. But that has changed, she said.
“We’ve been declining the last three years,” she said. Part of that has had to do with the success of those hunting with hounds.
“Hound hunters are still having a lot of success,” she said. “We know our harvest season is having an impact.”
Conversely, Tucker said, those hunting without dogs are having less success than in previous years.
Tucker said data from the first three years of the study indicates the survival rate of the North Dakota mountain lion population is significantly lower than other states.
She said lions here showed a survival rate of 42 percent for two years following their capture and tagging. That compares to survival rates of 59 percent in the Pacific Northwest, 64-74 percent in Utah and 67-97 percent in Canada where similar studies have been conducted.
At least part of that may be attributed to the fact that mountain lions’ primary range in North Dakota, the Badlands, is a relatively small and closed system.
Tucker said it also suggests the state’s population is lower than originally thought.
As far as feeding habits, lions rely mainly on deer — mulies and white tails — for most of their diet.
Porcupines and beaver, however, also play a significant role in the makeup of mountain lion diets.
John Jenks, the principal investigator at SDSU, said that is not a big surprise because lions are known to scavenge whatever food is readily available.
“Porcupines are classic prey for mountain lions in South Dakota,” he said.
Jenks said the lions in the Black Hills turned to stalking deer for food after they had thinned out the porcupine numbers.
And, with larger prey, Jenks said, the success rate for kills is not all that high due to the method in which they hunt.
Mountain lions prefer to ambush their prey from a high vantage point to get a running start.
He said the scavenge rate for North Dakota lions in the study was around 7 percent of their diet, on par with lions in other states.
He said interestingly, mountain lions here don’t tend to hunt larger animals like bighorn sheep or elk.
Jenks said lions are solitary hunters and it may be they haven’t yet figured out how to kill larger prey.
He added that based on a small population sample of lions studies, predation on livestock appeared to be minimal.
Jenks said there has been some evidence of lions feeding on livestock, but it’s not known if the lions killed or scavenged the carcasses.
He said there also has been evidence of lions killing coyotes and of injuries to the cats themselves, likely from territorial disputes between males.
He said the second phase of the study will focus more on habitat selection and validate population data and home range and survival rates from the first study.
Tucker said male lions in the Badlands have been shown to have a home range twice that of females — about 89 square miles compared to 42 — which is on the lower end of scale in comparison to other states.
Jenks said the immigration of two males from the Charles M. Russell National Wildlife Refuge near Fort Peck, Mont., is a positive for Badlands population — at least from a genetic diversity standpoint. The first phase of the study has shown mountain lions are breeding only in the northern portion of the Badlands.
Tucker said the next three years of the study will include an SDSU graduate student, the second student working on a master’s degree, on the ground in North Dakota.
She said the goal is to capture and track more lions to add to the data from the first three years.
“We’d love to get another 22 cats, but we’ll take what we can get,” Tucker said.
As far as any conclusive findings early on, Tucker said the study may indicate North Dakota’s mountain lion population may never be able to support a hunting season with a higher quota.
Reach reporter Brian Gehring at 701-250-8254 or firstname.lastname@example.org.