Cooperative Fish and Wildlife Research Units Program: Wyoming
Education, Research and Technical Assistance for Managing Our Natural Resources

Although moose are relatively new to the Snowy Range of southwestern Wyoming following translocations in the 1980s, the herd harbors some of the most coveted moose permits in the state and consistently receives the attention of Governor’s Permit hunters, because of the production of world-class moose. Nevertheless, given the difficulty in surveying and monitoring this herd, current levels of herd performance and the sustainability of current harvest practices have been largely unknown. Moreover, the striking alterations to habitat caused by the bark-beetle epidemic has resulted in increased concern for herd performance. The Snowy Range Moose Project commenced in March 2015 with the capture of 30 adult female moose in the Snowy Range. During the past 1.5 years, we documented mortality levels for adult female moose that were surprisingly high, and performance metrics (pregnancy, calf recruitment, nutritional condition) were less than expected given the low population density and the anticipation of a high-performing herd. Adult survival is typically high and invariable for large herbivores, which results in annual variation in recruitment of young underpinning population growth. Nevertheless, survival of adult females will ultimately dictate population trajectory when their survival is suppressed. Documented mortalities have occurred throughout the year, and were associated mostly with old females and those in poor nutritional condition. The contribution or interactive effects of disease, as has been documented in other moose populations, remains uncertain. Our overall goal is to seek a better understanding of the factors contributing to the high rates of mortality for adult female moose, along with continued monitoring of habitat and range conditions, while continuing efforts for annual monitoring.