"White-tailed deer (Odocoileus virginianus) fawns are the primary summer prey of wolves in Minnesota. (Frenzel 1974, Van Bellenberghe et al. 1975, Fritts and Mech 1981, Nelson and Mech 1986). Vulnerability of fawns ins at least partly a direct function of the previous winter’s severity (Mech and Karns 1977, Mech et al. 1987) because of prenatal nutritional influences (Verme 1962)."(269-270)

"Wolves likely resort to secondary prey when primary prey is less available or vulnerable. If so, domestic animals may constitute secondary prey, and may be killed at a higher frequency when deer fawns are less available."(270)

"Our hypothesis was that wolf depredation on domestic animals is inversely related to winter severity. A significant inverse relationship between measures of domestic animal depredation and winter severity would support this hypothesis and would be consistent with our explanation that wolves take domestic animals inversely to the availability of deer fawns. Another explanation would be that snow remains longer after severe winters, and farmers keep livestock confined later, reducing losses to wolves."(270)

"Results of correlation analyses supported our hypothesis that wolf depredation on domestic animals was inversely related to severity of the previous winter."(270)

"The lack of a significant relationship in May also is consistent with both explanations because livestock are always on open range in May regardless of winter severity, and deer fawns are not born until late May and early June."(271)

"Further evidence for the fawn-vulnerability explanation was found in the decreasing r-values after June (Table 1), because deer fawns are most vulnerable immediately after birth in late May and June."(271)

"We recognize that our analyses do not confirm cause and effect."(271)