White-tailed deer
population looking good

Game Range Ramblin's

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


April 19, 2001
Seeley Swan Pathfinder
Seeley Lake, Montana

by Mike Thompson

White-tailed deer wintered well.

Data to support this conclusion come from early spring surveys of fawn/adult ratios in the Clearwater Valley, below Seeley Lake.

Sounds real stuffy and scientific, doesn't it?

You wouldn't think so if you spent an evening with Sharon and me, eating chips and swilling pop, counting "mommies" and "babies" from the comfort of our pickup truck. In fact, counting and classifying white-tailed deer has become such a pleasant part of our spring season that we're more apt to blend the "work" into our weekend or evening recreation instead of the normal workday. So, we drive our personal vehicle and don't claim any work hours or expenses, which leaves us free to come and go as we please.

An evening last week was a good example.

The Blackfoot-Clearwater Chapter of the Rocky Mountain Elk Foundation was holding its weekly meeting to plan this year's banquet for elk habitat. The Game Range 50th Anniversary Project has been its focus for the past two years. Even though the Phase I purchase of 856 acres was completed last June, there still are expenses associated with the other phases of the 50th Anniversary Project, and the Chapter is still selling Conrad Rowe's framed photograph of elk on the Game Range to raise funds. Sharon and I like to keep in touch with our friends in the Chapter to express our gratitude for what has already been accomplished, and to coordinate on new and continuing efforts on the other project phases.

The meeting was at 7:00 P.M. at the Double Arrow Lodge, which gave us an hour or so to classify whitetails along the trip from Clearwater Junction to Seeley Lake.

What exactly does it mean to "classify" whitetails?

In the spring, it means identifying fawns and adults. The fawns were born last June, so our spring counts indicate how many fawns are poised to survive their first full yeartheir most vulnerable yearof life. We can only count the rest as adults at this time of year, when the bucks don't carry antlers.

We had counted 39 adults and 19 fawns by the time we got to the Double Arrow, when we ran into Larry Marx and explained what we were doing.

"Well, you can count another 65 between here and the Valley Market right now if you want to," Larry advised us. "It'll only take you about 10 minutes."

So, we rushed backed outside and classified 54 adults and 31 fawns without missing much of the meeting. We got back just in time to report that there were at least 85 deer where Larry had predicted we would find 65.

After reporting our count, and updating the group on the progress of Phase IIthe project to exchange about 3,000 acres of Plum Creek inholdings within the Game Range to DNRCSharon and I excused ourselves early to finish our survey before dark. This allowed us to add another 33 adults and 14 fawns on the way home.

Combined with the 65 adults and 25 fawns we counted up Blanchard Creek the week before, we finished with a classified total of 280 white-tailed deer to represent Hunting Districts 282 and 285 this spring.

This total of 280 isn't worth much as an indicator of deer numbers and population trends. It's almost impossible to get a reliable count of a large, white-tailed deer population by any means, much less by the drive-around method that Sharon and I employ. Basically, the total of 280 deer tells us that we obtained a reasonable sample size of deer for calculating a representative ratio of fawns to adults.

It's the ratio of fawns to adults that is worthy of comparison from year to year. By using this ratio, it's not necessary to obtain accurate total counts to learn whether it's been a good year for whitetails or not. As long as the deer distribute themselves in roughly the same way from year to year, and as long as the proportion of bucks in the population doesn't vary radically, the changes we see in ratios of fawns per 100 adults from one year to the next should reflect real variations in fawn survival rates.

This year's result was a ratio of 47 fawns per 100 adults, which was down slightly from last year's ratio of 52. Biologically, the difference between the two years is negligible. Both ratios reflect excellent production and survival of young deer, which should be fueling a continued strong increase in the deer population.

On Sunday, Sharon and I came up with a different result in white-tailed deer south of Highway 200, along the Blackfoot River from the Scotty Brown Bridge area to Sunset Hill. We classified 235 deer and came up with a ratio of 35 fawns per 100 adults. Although lower than we saw in the Clearwater drainage, this ratio is still within the normal range, and does not give cause for alarm.

When fawns fare well, so do adults. While adults accumulate layers of fat in summer to help them through the winter, fawns use all their energy for growth and so are more vulnerable to malnutrition in winter. The female fawns that make it through their first winter have weathered the most trying period of their lives and have much higher expectancies for a long life span thereafter.

Maybe that's why we've been seeing so many fit and sassy looking adult deer over the past couple of weeks. And, it's why we can expect to see another good crop of fawns in just another two months.


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