Elk Management Insights
from Gravelly Mountains

 

Game Range Ramblin's



Game Range Articles
by Mike Thompson,
FW&P wildlife biologist,
writing for the Pathfinder

 


August 30, 2001
Seeley Swan Pathfinder
Seeley Lake, Montana


by Mike Thompson

 

After many years' absence, my path seems to be crossing the Gravelly Mountains again, first with a committee meeting at Wall Creek Wildlife Management Area (WMA) to review FWP's game damage policy, and now with the opportunity to review the draft final report of FWP's Gravelly-Snowcrest Elk Study.

The elk study was begun by FWP research biologists Terry Lonner and Phil Schladweiler in 1984, which was when I had last bunked at Wall Creek. There was a little more excitement in the air then. Next morning, dozens of us mustered at daybreak, took our positions behind sagebrush and juniper in an otherwise open draw, and tackled elk after a helicopter drove several at a time into windrows of propped up netting. After only a few hours work, we marked the first 74 elk for the Gravelly-Snowcrest Elk Study in this stimulating fashion.

Although tempting, we have never employed this method to capture and collar elk on the Blackfoot-Clearwater Game Range. It has the advantage of high efficiency, but in my opinion requires far more open space than exists on the Game Range. I really wouldn't want to risk putting dozens of elk on a dead run in an area where some could break off and cross in front of traffic on either Highway 83 or 200 before the helicopter could gather them up again.

Another consideration is that we rely on the helicopter to census elk on the Game Range every winter. The last thing we want to do with a capture operation is teach elk to run like the wind whenever they hear the helicopter revving up in the distance. Our census precision would probably run away with them.

While reading the Gravellys report, I'm remembering there are other major differences between the elk habitat and elk populations of the Gravelly-Snowcrest Mountains southwest of Ennis and those of the Blackfoot-Clearwater Game Range, here in our backyard.

Like size, for one thing. The Gravelly-Snowcrest elk population ranges over an area of 4 million acres. That's not a misprint. Four million acres! This is an area roughly 8 times larger than the yearlong range of the Blackfoot-Clearwater elk population. If you're looking for similarities, the Gravelly-Snowcrest study area is almost exactly the same size as the whole Bob Marshall Elk Management Unit, which includes all the country from Highway 200 to Glacier Park, and from Seeley Lake to Choteau.

The size and productivity (for elk) of the principal winter ranges also differs. Wall Creek WMA is a bit over 6,000 acres in size. Although the Blackfoot-Clearwater boasts a size of 67,000 acres, the actual elk winter range is closer to 25,000 acres. Even so, it is about 4 times larger than Wall Creek.

But, Wall Creek supported more than 2,000 elk in the winter of 2000. That's more than twice the number of elk (856) that we counted on the Blackfoot-Clearwater that year.

Wall Creek is a classic East Slope "elk factory," with lots of wide open spaces, plenty of grass, and occasional slope-baring winds in winter. By comparison, the Blackfoot-Clearwater is a forested snow hole, yet more diverse. Its habitat is less ideal for elk perhaps, but more productive these days for mule deer and white-tailed deer. If you add in the elk population units that are associated with the Sun River and the rest of the Rocky Mountain Front, the competition for elk numbers evens out. It is thought that the Bob Marshall Elk Management Unit (including the Blackfoot-Clearwater and Rocky Mountain Front) can and does support 9,000-11,000 elk. Surveys indicated a winter population of about 12,000 elk across a similar-sized area in the Gravelly-Snowcrest in the winter of 2000.

It wasn't always so. Whereas the Bob Marshall population has been pretty stable over the past 10 years or so, researchers documented an increase of almost 100% in the southwest Montana herd over the same period of time. Comparable numbers of elk (about 1,000) were counted annually on the Wall Creek and Blackfoot-Clearwater areas in the late 1980s and early 1990s.

What blew the lid off the Gravelly-Snowcrest elk population in the 1990s? Frantically, I flipped through the pages of the draft report for an explanationa punchline.

Well, it appears that elk population growth eventually overwhelmed practical constraints for controlling it. Numbers of permits to harvest antlerless elk seemingly reached a saturation point beyond which increases in permits yielded little additional harvest. Why? One factor was a perceived shortage of hard-core hunters with high skill-levels. Also, with large numbers of antlerless permits available for several years, many hunters had already killed one or more cow elk in the past and were less interested in working hard for another as the years went by.

Due to these, and maybe other factors, researchers estimated that a maximum of 2,750 antlerless permits would provide an "acceptable" hunting experience each year across the Gravelly-Snowcrest study area. Given current calf production and survival rates, this level of permits would be expected to maintain a zero growth rate on a population size of less than 10,000 elk, or only about 80% of the current level.

It may take one or two severe winters, hopefully in the very near future in southwest Montana, to increase natural mortality rates and decrease productivity enough to allow hunting harvest to control elk numbers again in the Gravelly-Snowcrest area.

All of which intrigues me to no end. We were concerned about our abilities to control the growth of the Blackfoot-Clearwater elk population in the early 1990s. We responded in reaction to excessive game damage levels on private lands with a concerted effort to cause a managed decline in elk numbers. We were successful in this effort, to the point that we worried about recruitment rates of young bulls to fuel the annual general harvest. At that time (1996) we cut back the number of antlerless licenses to allow the population to rebound. While we have been generally successful in this effort as well, our rates of population growth have been lower than expected, due to a setback after the hard winter of 1996-97, and unexpectedly low calf survival thereafter.

Now I need to sign off so I can review the information in all those pages I skipped over in the Gravellys report to get to the punchline