. The Canadian field-naturalist. 158 The Canadian Field-Naturalist Vol. 93 Road locations were converted to their lati- tudinal equivalents using 1:63 360 scale maps of USGS Topography Series. For each survey series a mean latitudinal position of Caribou was calculated as described by Cameron and Whitten (1979). Results and Discussion Caribou Numbers and Group Composition Numbers and group composition of Caribou observed from the haul road during each survey period are given in Table 1. Groups with one or more "unknowns" (see Methods) were excluded from composition calculations. Nine
. The Canadian field-naturalist. 158 The Canadian Field-Naturalist Vol. 93 Road locations were converted to their lati- tudinal equivalents using 1:63 360 scale maps of USGS Topography Series. For each survey series a mean latitudinal position of Caribou was calculated as described by Cameron and Whitten (1979). Results and Discussion Caribou Numbers and Group Composition Numbers and group composition of Caribou observed from the haul road during each survey period are given in Table 1. Groups with one or more "unknowns" (see Methods) were excluded from composition calculations. Ninety-eight percent of the total Caribou sighted during summer were successfully classified. During fall, however, bright sun and snow frequently created distortion which precluded classification at distances greater than about 400 m, and entire groups were recorded as unknowns; the pro- portion classified decreased to 56%. Cows and yearlings were often difficult to distinguish, and many such individuals were classified as "adults" (see Methods) when more specific identification was impossible. Calves, however, were relatively easy to recognize and reported percentages are thought to be very reliable. Similarly, iden- tification of bulls was rarely in question. During summer 13% of total Caribou ob- served from the haul road were calves, com- pared with a corresponding value of 21% obtained by systematic aerial survey of a larger area roughly centered on the pipeline route (Table I). In contrast, a mean of 17% calves was observed in fall during both road and aerial surveys, indicating that a representative portion of the herd was present along the corridor. Within each season, calf percentages for groups with calves were similar for road and aerial observations (Table 1). It can be calculated from the summer road data in Table 1, however, that the number of Caribou observed in groups with calves averaged 33% of the total classified, whereas 60% of Caribou classified by a
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