Mid-Day Temperature Variation Influences Seasonal Habitat Selection by Moose

We tracked 122 female moose in northwestern Ontario, Canada, using global positioning system (GPS) radio-collars between 1995 and 2001. We used step-selection functions (SSF) to evaluate changes in moose habitat selection as a function of temperature across seasons (summer and winter), stand types, and stand heights. We obtained mean activity levels of moose within stand types and across seasons from motion sensors in the collars. Selection increased for aquatic stand types as a function of temperature across both summer and winter. Selection for stand height was also temperature-dependent, with tall stands being most favored at warm temperatures and least favored at cold temperatures. Moose activity levels increased slightly at higher temperatures during the winter but were mostly constant, whereas summer activity declined significantly with increasing temperature. Seasonal activity levels were mostly constant within habitats, but activity was consistently higher in aquatic habitats compared to woody habitats, with the highest mean activity levels observed when moose were located in open water and marshes during the summer. Our findings corroborate the work of others that moose primarily select habitat based on documented foraging requirements, whereas they may alter mid-day selection for specific stand types providing thermal cover under varied temperatures, indicating a behavioral response to thermoregulatory needs. Increased activity levels at low summer temperatures, and in habitats found to provide thermal cover, support the conclusion that moose may alter their activity to alleviate heat stress, and that temperature-mediated changes in habitat selection may facilitate otherwise energetically costly behavior (e.g., movement). (c) 2015 The Wildlife Society.