"By integrating the effect of rain, temperature and snow cover in a population model, our deterministic analysis reveals that snow depth is the main factor affecting the population growth rate through its effect on winter adult survival. . . During the last 15 years, direct field observations and locations of harvested wild turkeys showed that wild turkey abundance has been increasing northward. . . Our stochastic analysis shows that if harsh or extreme snowfall occurs with variable temperature and rainfall similar to those observed over our historical period, the population at the northern species range will decline to extinction. . . The northernmost population is projected to decline by 2100."