We investigate different aspects of the resources that supply energy to a beehive. Quantitatively, a resource can provide a certain amount of nectar per time unit. Qualitatively, the assessment of this resource depends on more subtle parameters such as the flower species that produces the nectar, the density of the resource, as well as the availability of the resource which is a function of its distance from the hive and of other factors such as the wind. These environmental parameters influence the potential of the hive to store enough honey in order for it to stay alive during the cold winter months. To understand how costly it is for a colony to survive through winter, we study how much honey the bees in a hive expend during the cold season, and the influence of factors such as the size of the colony on the depletion of honey.