. The Canadian field-naturalist. 1981 POTVIN AND AL.: DEER MORTALITY IN QUEBEC. Figure 1. Extent of the Pohenegamook wintering area in 1972-1974 and 1978. Materials and Methods Aerial surveys were used to map the extent of the wintering area. Each spring or early summer pellet- group counts were taken to estimate the deer popula- tion of the previous winter. Sampling plots 2 X 40 m were systematically laid along transects equally spaced and perpendicular to contour intervals. Defe- cation rate was fixed at 13 pellet-groups per day and number of yarding days was set at 165 (mid- November to end
. The Canadian field-naturalist. 1981 POTVIN AND AL.: DEER MORTALITY IN QUEBEC. Figure 1. Extent of the Pohenegamook wintering area in 1972-1974 and 1978. Materials and Methods Aerial surveys were used to map the extent of the wintering area. Each spring or early summer pellet- group counts were taken to estimate the deer popula- tion of the previous winter. Sampling plots 2 X 40 m were systematically laid along transects equally spaced and perpendicular to contour intervals. Defe- cation rate was fixed at 13 pellet-groups per day and number of yarding days was set at 165 (mid- November to end of April). Snow depth was monitored every winter in a conif- erous stand. From 1974 to 1979 systematic dead-body surveys were conducted in the spring, along the same transects used for the pellet-group count, and covered 5-10% of the yard. Dead deer were aged by tooth replacement and wear (Severinghaus 1949) and their physical condition was evaluated by the femur mar- row fat content (Cheatum 1949). Deer whose mortal- ity cause was not evident and with less than 25% fat in the bone marrow were classified as dead by starvation. Results The wintering area decreased from 30 km^ in 1972-1974to only 11 km^ in I978(Figure l).Thedeer population underwent a 71% decline from 1972 to 1979 passing from 480 to 140 deer (Table I). According to snow depth, winters of 1975 and 1977 were the most severe (Figure 2). Under coniferous cover, snow depth exceeded 50 cm for 17 wk or more and reached 70 cm from late January or early Febru- ary. No supporting crust was present during these two winters except at the end. On the contrary, in 1973 and. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Ottawa Field-Naturalists' Club. Ottawa, Ottawa Field-Naturalists' Club
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