Female moose pregnancy and survival in Colorado

Wildlife management agencies are obliged to provide evidence-based management recommendations to stakeholders. However, the allocation of resources is rarely uniform among species. The consideration of life-history characteristics of moose offers wildlife managers a more robust understanding of population ecology, while also providing insight into potential limiting factors for long-term management. We measured the survival of adult female moose, nutritional condition and pregnancy status of adult female moose, and winter calf-at-heel ratios as a means to document productivity and life-history characteristics of moose in Colorado. We measured these parameters from three distinct geographical regions in Colorado, from 2014-2020. There was very little geographical or annual variation in survival rates, although variation in monthly survival rates was observed. The primary source of mortality of moose was in fall during hunting seasons, whereas natural mortality events typically occurred between January and May. Pregnancy status of moose was best modeled using body condition score, year, and presence of a 6-month-old calf from the previous breeding season. A positive relationship between the percent ingesta-free body fat and moose pregnancy probability was evident.