White-tailed deer (Odocoileus virginianus) survival is influenced by many factors including disease, predation, weather, and hunter harvest. In the Upper Peninsula of Michigan (UP), deer survival is strongly influenced by winter food supply and cover. Deer commonly rely on felled tree tops and subsequent growth of tree saplings for winter food. Additionally, deer seek landscapes with a high proportion of conifer trees, such as cedar and hemlock, to obtain shelter from snow and wind. The availability of these habitats effects over-winter survival in the UP.
Predators also play a role in deer survival, particularly fawn survival during spring and summer. Although some predators (such as coyotes) are able to take deer of any age, other predators (such as black bears) are able to catch fawns only during the first couple weeks of life. During winter, when deer are hampered by snow and in poor physical condition, predators are able to more readily kill deer. Understanding deer survival, and the factors that influence it throughout the year, is important for proper management of the deer herd.
Historically, deer abundance in the UP has been affected by the intensity of timber harvesting and winter severity. Although these factors still exert a strong influence on deer populations, the role of predation is receiving more attention by both sportspersons and deer managers. Research is needed to better understand the impact of predation on deer, while also determining how predation is influenced by winter weather and deer habitat conditions.