Studying the Winter Nutritional Status of Moose and its Relationship to Moose Survival, the Population Trend, and Climate Change in a Declining Population in Northeastern Minnesota

Winter nutritional restriction of moose and other northern ungulates may be physiologically assessed by serial collection and chemical analysis of fresh urine in snow (snow-urine). Controlled studies of captive ungulate species have demonstrated that urinary urea nitrogen:creatinine (UN:C) ratios have significant value as a metric of winter nutritional status. This technique allows the biologist’s team to non-invasively and cost-effectively sample large numbers of moose (100s of specimens) at the population level over vast landscapes throughout winter to investigate ecological relationships between varyingly levels of nutritional restriction and survival, population dynamics, habitat, and other environmental factors. It has enhanced our understanding of nutritional restriction relative to aspects of winter mortality of elk and bison in Yellowstone National Park, and to moose population dynamics on Isle Royale impacted by a winter tick (Dermacentor albipictus) epizootic and influenced by regional differences in habitat.