Biologists look to find out what ails South Fork elk herd

Montana Fish, Wildlife and Parks hopes to collar 16 elk in the Bob Marshall Wilderness this month as part of a study to better determine why the population has been on the decline in the South Fork of the Flathead.

Biologists have skied into Big Prairie and will attempt to trap and collar the elk, according to Neil Anderson, Region 1 wildlife manager.

The South Fork has traditionally been home to a herd of about 1,000 elk, but lately the estimate is closer to 300. Anderson said the hypothesis is wildfires coupled with a full suite of predators, including mountain lions, grizzlies, wolves and black bears in the drainage is impacting the elk herd.

While wildfires can be beneficial, some of the fires in the past few years have burned overly hot, destroying cover in winter range. The Bear Creek Fire of 2015 burned very hot in the north end of the South Fork, for example. It takes years for forests to grow back and beneficial brush species also take time to grow back after fires.

“Those elk are really restricted in winter range,” Anderson said.

Being concentrated also makes them more susceptible to predation, Anderson noted.

The bulk of the South Fork inside the wilderness is in Hunting District 150. No cow hunting is allowed in the district.

By tracking the collared elk movements, biologists hope to gain a better understanding of the population and how they’re using the landscape. The collars typically last about three years.

The state already has 14 cows collared in the Hungry Horse area outside of the wilderness, Anderson said. Those were collared between Dry Parks Mountain and Lower Twin Creek.  

Limited access within the Bob Marshall Wilderness poses unique challenges to study and manage wildlife effectively. There is a notable lack of contemporary data on elk vital rates, seasonal habitat selection, and movement patterns within this wilderness area.

The state and Forest Service staff are venturing into the remote backcountry the old-fashioned way, relying on cross-country touring ski equipment to navigate the snow-covered terrain to get to Big Prairie. Crews plan to spend up to four weeks working in the wilderness.

With technical support from the Flathead National Forest Spotted Bear Ranger District and funding from the Rocky Mountain Elk Foundation, this project will employ GPS radio collars.

Anderson noted calf recruitment has been down in recent years, an indication that the population is in decline. Biologists in the spring count the number calves to cows. That ratio should be in the 20s, lately it’s been in the teens.

Unlike other parts of the Flathead Valley, it’s difficult to hunt predators in the Bob Marshall due to its remote location and heavy snows.

Hunting success for elk has also been lower. According to FWP’s 2023 elk report, the number of bulls harvested in 150 reached a low of 41 in 2021 and a high of 79 in 2016 in the past 10 years. The last time it was above 100 was in 2013, when 114 elk were taken.

From 2019-2023 the average bull harvest was 51. From 2018 to 2022 it was 54.

“For years, hunters have sounded the alarm about elk declines in the South Fork. However, FWP’s response has rung hollow due to limited information and management tools. This project will provide information that will improve discussions on factors limiting elk number in the Bob Marshall and help to formulate potential management actions,” said Franz Ingelfinger, FWP’s wildlife biologist leading the project. “Understanding elk movements, habitat use, and survival in the South Fork is crucial to effective wildlife management. This research will help identify factors influencing elk numbers and inform management decisions aimed at long-term health of elk herds in the South Fork.”

“To be clear, this is a study of limited scope,” Ingelfinger said. “Thirty collars distributed on cow elk across the South Fork won’t solve the riddle of the South Fork. However, we hope to glean important information that will improve management.”

FWP and the U.S. Forest Service said they are committed to protecting wilderness character and minimizing impacts on wildlife. Captures will be conducted using approved wildlife handling techniques to ensure the safety and well-being of the elk. Additionally, field operations will be planned to align with wilderness management principles, including preserving the natural integrity of the landscape.