Moose (Alces alces) are a recognizable species throughout the mountainous regions of Montana. As the largest member of the deer family, their presence indicates healthy forest and riparian ecosystems across the state. Understanding the number of moose and their distribution is a major priority for Montana Fish, Wildlife & Parks (FWP). Population data informs conservation strategies, determines annual hunting quotas, and identifies environmental pressures affecting the species’ long-term survival.
The Current Population Estimate
Montana’s statewide moose population is not determined by a simple census but is a carefully calculated estimate derived from extensive scientific research. The most recent comprehensive study, a decade-long effort by FWP, estimates the statewide population to be between 9,800 and 11,700 animals.
This estimate represents an average abundance of approximately 10,380 moose across two periods: 2012–2016 and 2021–2023. While initial reports suggested a widespread decline, the final results of the FWP study indicate a generally stable trend in the three primary study areas. The population’s health varies regionally, with some areas showing a slight decline while others demonstrate growth.
Geographic Distribution and Key Habitats
Moose are widely distributed across the western half of Montana, where rugged terrain and dense forests provide their preferred habitat. The Shiras subspecies, which inhabits Montana, is associated with areas rich in water and specific types of vegetation. This includes the mesic, or moist, forested environments of the Cabinet-Salish mountains in the northwest.
Another concentration is found in the southwest, particularly the Big Hole Valley, known for its extensive willow fen habitats. The Rocky Mountain Front also supports a healthy moose population. Even areas in the eastern prairie landscapes, like riparian corridors along the Missouri River, host moose populations that rely heavily on willow communities for sustenance. Shrubs like willow and wild lilac make up a large portion of their year-round forage.
Methods for Population Monitoring
Counting moose is challenging because they are solitary, widely dispersed, and adept at hiding within dense cover, making traditional aerial surveys ineffective. To overcome this, FWP developed a robust monitoring approach relying on advanced technology and citizen science. A significant component involves using the observations of deer and elk hunters, who spend millions of days afield across the state.
FWP uses annual phone surveys of these hunters to collect and map thousands of moose sightings. This hunter-assisted monitoring is combined with intensive tracking of collared animals to provide vital scientific details. Researchers fitted 193 adult female moose with GPS and VHF collars in key study areas to monitor their movements, survival rates, and reproductive success over the ten-year period. This combination of citizen-reported data and direct tracking allows biologists to create sophisticated models that estimate population size and trends with greater accuracy than previous methods.
Factors Influencing Moose Population Health
The health of Montana’s moose population is influenced by a complex interplay of environmental factors and biological stressors. The availability of high-quality nutritional forage has been identified as the most significant factor affecting population growth and reproductive success. Moose rely on energy-rich plants, and a healthy supply of browse, particularly willow, directly impacts the survival of adult females and their calves.
Predation is a factor, with wolves preying on adult cow moose more frequently than mountain lions or bears in the study areas. However, mortality is often driven by health-related issues, primarily parasites and disease. The carotid arterial worm (Elaeophora schneideri) and winter ticks (Dermacentor albipictus) pose substantial threats, with high loads of arterial worms associated with increased adult moose mortality, especially in the Big Hole study area.
Climate change introduces another variable, as warmer temperatures and reduced snowpack can increase the prevalence and severity of winter tick infestations. Although tick loads in Montana have not been as devastating as in some eastern states, this remains a concern for the future. Management decisions, including the reduction of hunting permits by more than 50% in recent years, are carefully adjusted based on the scientific understanding of regional population health and the pressures they face.