Montana Fish, Wildlife & Parks biologists in west-central Montana say that mule deer spring surveys showed that another mild winter helped with fawn survival and recruitment into the population across several areas of the region.
Fawns have high mortality during their first year of life, and those that survive are considered "recruited" into the population. Recruitment metrics are an important indicator for growth in the population, which means that years with high fawn recruitment generally lead to population growth and potentially more hunting opportunities in successive years.
Specifically, west-central Montana's Region 2 biologists reported high fawn recruitment in several survey areas in the Upper and Lower Clark Fork and Bitterroot Valley. In the Upper 'Clark Fork Face' trend area in Hunting Districts (HDs) 291 and 292, fawn recruitment was up 34 percent from the previous year, with fawn to adult ratios of 43 fawns per 100 adults and 46 fawns per 100 adults respectively. In HD 202 in the Lower Clark Fork, fawn recruitment has remained high over the last several years with fawn to adult ratios above 50 fawns per 100 adults.
Hunting District 270 in the southeast Bitterroot Valley is a desirable limited entry buck hunting opportunity and has had the longest consistent history of survey data collection in the region. This year's fawn recruitment was 52 fawns per 100 adults, a 31 percent increase from the previous year. Spring surveys in this district have also shown an upward trend in deer numbers over the last 5-10 years, although this year's count (1,753) was slightly lower than last year (2,018).
This was one example of an area in state where spring survey conditions were more challenging than usual this season. A mild winter and early spring meant that deer were more spread out and not concentrated in smaller greening landscapes like they often are, making overall counts harder to obtain in some areas.
Annual counts can fluctuate from year to year based on survey conditions, which is why biologists look at the trend in the data over successive years, combined with other information, to get a clearer understanding of population trajectory.
Buck harvest is another important metric that can be an indicator for population trends in districts that are managed on a general hunting license. In west-central Montana, several districts are showing an increasing trend in buck harvest in the short-term (five years) and/or long-term (20 years), which is also a positive indicator for more widespread mule deer population growth across the region.
Notable general license hunting districts with increasing buck harvest trends in the short and/or long-term are HDs 201, 216, 217, 281, 285, 292, 293, and 298. Other hunting districts, such as HD 200 and 215, are stable, and HD 214 shows a decreasing trend. Other districts are difficult to evaluate because of special harvest regulations or hunting district boundary changes in recent years.
Weather conditions can have dramatic impacts on mule deer populations. Hard winters and summer drought can lead to low survival, especially for fawns. In west-central Montana, the last three winters have been mild with this last winter exceptionally mild, with little snow and higher than normal temperatures, creating favorable conditions for mule deer and other big game. The mild winter in 2025-26 is likely the primary driver for the high fawn recruitment recorded by biologists this year.
Other factors that can affect mule deer numbers are habitat conditions, predation, disease, and competition with white-tailed deer and elk. Right now, west-central Montana Region 2 biologists are closely tracking the emergence of Chronic Wasting Disease in mule deer in the Upper Clark Fork in HDs 213 and 215, where two new positive samples were detected in recent months after the first positive sample was detected during the 2023-24 hunting season.