. The Canadian field-naturalist. 160 The Canadian Field-Naturalist Vol. 94 Table 1—Habitat use by White-tailed Ptarmigan, and nfiean distance ± so (km) of flocks during January and February of 1977-1978 from nearest known breeding areas No. of birds (flocks) Habitat type 1977 1978 Mean distance (km) 1977 1978 Alpine cirque Treeline krummholz Subalpine forest Stream course 58(10) 9 (2) 6 (2) 15 (2) 56 (6) 28 (5) 0 ± + ± ± ± were observed more than once, based on observations of marked birds and locations of individual flocks. Average flock size for the two w
. The Canadian field-naturalist. 160 The Canadian Field-Naturalist Vol. 94 Table 1—Habitat use by White-tailed Ptarmigan, and nfiean distance ± so (km) of flocks during January and February of 1977-1978 from nearest known breeding areas No. of birds (flocks) Habitat type 1977 1978 Mean distance (km) 1977 1978 Alpine cirque Treeline krummholz Subalpine forest Stream course 58(10) 9 (2) 6 (2) 15 (2) 56 (6) 28 (5) 0 ± + ± ± ± were observed more than once, based on observations of marked birds and locations of individual flocks. Average flock size for the two winters was six birds (range 2-20). Most ptarmigan in 1977 were observed in alpine cirques (Table 1), areas typically used in spring and summer (Herzog 1977). Some marked individuals (seven males, three females) had not migrated from their breeding areas. Few ptarmigan were detected downslope of cirques in the subalpine and stream course habitats (Table 1). The general lack of ptarmi- gan sign (tracks and snow roosts) below alpine areas also indicated that most birds probably remained at higher elevations. In contrast, ptarmigan were not observed during any searches of cirque habitat in 1978; virtually all sightings occurred in the subalpine and stream course habitats (Table 1). Habitat use was different between the years (chi-square test, P<). The distances from the treeline krummholz and subalpine forest habitats used by ptarmigan to the nearest breeding areas were similar both years (Table 1). Birds were sighted at the same general locations within these habitats each year, indicating the suitabil- ity of these areas during both winters. Ptarmigan win- tered along the same stream courses each year but were at lower elevations in 1978 (Table 1). Ptarmigan distribution was mainly affected by the availability of food resources, primarily willow. In 1977, willows remained exposed above the snow in cirque habitats (Figure 1), and birds were frequently observed feedin
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