The red deer (Cervus elaphus) are among the most important game species in Norway, with a tenfold increase in harvest over the last few decades. Despite its importance, information regarding red deer habitat selection is limited. In this study, year-round habitat selection at the within home range scale was investigated using data from female red deer equipped with either VHF- or GPS-collars in the county of Sogn og Fjordane. I predicted that red deer habitat selection would be determined by spatial and seasonal fluctuations in forage quality and quantity, such that the habitats holding the mostnutritious forage would be selected through the year. I also predicted that the red deer would experience a trade-off between forage availability and safety, leading to more covered habitats being selected in daytime when visibility is good, and open habitats being selected at night-time. Habitat selection was investigated using resource selection functions, separated by season and time of day/state of activity to determine the underlying mechanisms. Red deer habitat selection changed through the seasons as would be expected if forage quality and quantity fluctuated through the year, and varied between habitats. Cultivated habitats were frequently selected by the red deer, and as these habitats are regarded to hold forage of relatively higher nutritional value than forage occurring naturally through most of the year, I argue that agricultural land and pastures are very important to the red deer. Habitat selection also changed with time of day/state of activity, suggesting a trade-off in habitat selection. Further evidence for a trade-off situation was found in the use of agricultural land and pastures, as the red deer select for these habitat types when availability is low, and use them less than expected when they are more readily available. Staying away from open, exposed areas when visibility is good should lower the chance of being detected, and therefore increase survival. Thisstudy of red deer habitat selection reminds us that habitat selection is a dynamic process. Resource selection functions are powerful tools to characterize habitat selection, and by extending the analyses by taking relevant temporal scales into account, the mechanisms behind habitat selection can be identified.