. The Canadian field-naturalist. Natural history; Sciences naturelles. \ r * Saskatchewan ^^> Inventoried areas 30 Ion Figure 1. Location of Weyerhaeuser's Grande Prairie Forest Management Area (FMA) and inventoried regions in western Alberta. same regions were investigated during the three inven- tories (Figure I). A few seismic lines were used repeat- edly over the years. In most cases, however, this was not possible because of access problems (overgrown vegetation, inappropriate snow conditions, or interfer- ing gas exploration or logging activities), or transfor- mation of seismic lines
. The Canadian field-naturalist. Natural history; Sciences naturelles. \ r * Saskatchewan ^^> Inventoried areas 30 Ion Figure 1. Location of Weyerhaeuser's Grande Prairie Forest Management Area (FMA) and inventoried regions in western Alberta. same regions were investigated during the three inven- tories (Figure I). A few seismic lines were used repeat- edly over the years. In most cases, however, this was not possible because of access problems (overgrown vegetation, inappropriate snow conditions, or interfer- ing gas exploration or logging activities), or transfor- mation of seismic lines into roads or pipelines. Habitat type classification along inventory transects was based on Proulx and Kariz (2005) (Table 1). Transects were traversed by snowmobiles (<10 km/h). We recorded only tracks that were well-defined and judged to be fresh; , less than 24 h old (subjective assessment based on the experience of the researcher). Due to the similarity between Fisher {Martes pennan- ti) and American Marten footprints (Halfpenny et al. 1995), when mustelid tracks were encountered, they were investigated on both sides of transects and with- in forest stands to find the best tracks available. The combination of footprint (pattern and size, presence/ absence of toe pad prints) and trail (gait, distance be- tween jumps, and dragging of the feet) characteristics were used to identify tracks (Murie 1975: Rezendes 1992; Halfpenny et al. 1995). Fisher tracks are usually larger and farther apart, although the footprints of fe- male Fishers and male American Martens may be of similar size. In winter, the undersurface of American Martens" feet is heavily covered with hair and toe pads do not show (Murie 1975; Rezendes 1992). The under- surface of Fishers' feet has sparse hair, and pads show well in clear prints (Halfpenny et al. 1995). Compared to American Martens. Fishers tend to walk more, leave straight trails, create troughs w hen walking in soft snow, drag their feet
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